# FFMPEG-CODECS - FFmpeg codecs - man(1) - [phpMan]

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## NAME
       ffmpeg-codecs - FFmpeg codecs

## DESCRIPTION
       This document describes the codecs (decoders and encoders) provided by the libavcodec
       library.

## CODEC OPTIONS
       libavcodec provides some generic global options, which can be set on all the encoders and
       decoders. In addition each codec may support so-called private options, which are specific
       for a given codec.

       Sometimes, a global option may only affect a specific kind of codec, and may be nonsensical
       or ignored by another, so you need to be aware of the meaning of the specified options. Also
       some options are meant only for decoding or encoding.

       Options may be set by specifying -_option_ _value_ in the FFmpeg tools, or by setting the value
       explicitly in the "AVCodecContext" options or using the _libavutil/opt.h_ API for programmatic
       use.

       The list of supported options follow:

       **b _**integer_ **(_**encoding,audio,video_**)**
           Set bitrate in bits/s. Default value is 200K.

       **ab _**integer_ **(_**encoding,audio_**)**
           Set audio bitrate (in bits/s). Default value is 128K.

       **bt _**integer_ **(_**encoding,video_**)**
           Set  video bitrate tolerance (in bits/s). In 1-pass mode, bitrate tolerance specifies how
           far ratecontrol is willing to deviate from the target average bitrate value. This is  not
           related to min/max bitrate. Lowering tolerance too much has an adverse effect on quality.

       **flags _**flags_ **(_**decoding/encoding,audio,video,subtitles_**)**
           Set generic flags.

           Possible values:

           **mv4 **Use four motion vector by macroblock (mpeg4).

           **qpel**
               Use 1/4 pel motion compensation.

           **loop**
               Use loop filter.

           **qscale**
               Use fixed qscale.

           **pass1**
               Use internal 2pass ratecontrol in first pass mode.

           **pass2**
               Use internal 2pass ratecontrol in second pass mode.

           **gray**
               Only decode/encode grayscale.

           **psnr**
               Set error[?] variables during encoding.

           **truncated**
               Input bitstream might be randomly truncated.

           **drop_changed**
               Don't  output  frames  whose  parameters  differ  from first decoded frame in stream.
               Error AVERROR_INPUT_CHANGED is returned when a frame is dropped.

           **ildct**
               Use interlaced DCT.

           **low_delay**
               Force low delay.

           **global_header**
               Place global headers in extradata instead of every keyframe.

           **bitexact**
               Only write platform-,  build-  and  time-independent  data.  (except  (I)DCT).   This
               ensures  that  file  and data checksums are reproducible and match between platforms.
               Its primary use is for regression testing.

           **aic **Apply H263 advanced intra coding / mpeg4 ac prediction.

           **ilme**
               Apply interlaced motion estimation.

           **cgop**
               Use closed gop.

           **output_corrupt**
               Output even potentially corrupted frames.

       **time_base _**rational_ _number_
           Set codec time base.

           It is the fundamental unit of time (in seconds) in terms of which  frame  timestamps  are
           represented.  For  fixed-fps  content,  timebase should be "1 / frame_rate" and timestamp
           increments should be identically 1.

       **g _**integer_ **(_**encoding,video_**)**
           Set the group of picture (GOP) size. Default value is 12.

       **ar _**integer_ **(_**decoding/encoding,audio_**)**
           Set audio sampling rate (in Hz).

       **ac _**integer_ **(_**decoding/encoding,audio_**)**
           Set number of audio channels.

       **cutoff _**integer_ **(_**encoding,audio_**)**
           Set cutoff  bandwidth.  (Supported  only  by  selected  encoders,  see  their  respective
           documentation sections.)

       **frame_size _**integer_ **(_**encoding,audio_**)**
           Set audio frame size.

           Each submitted frame except the last must contain exactly frame_size samples per channel.
           May  be  0  when  the codec has CODEC_CAP_VARIABLE_FRAME_SIZE set, in that case the frame
           size is not restricted. It is set by some decoders to indicate constant frame size.

       **frame_number _**integer_
           Set the frame number.

       **delay _**integer_
       **qcomp _**float_ **(_**encoding,video_**)**
           Set video quantizer scale compression (VBR). It is used as a constant in the  ratecontrol
           equation. Recommended range for default rc_eq: 0.0-1.0.

       **qblur _**float_ **(_**encoding,video_**)**
           Set video quantizer scale blur (VBR).

       **qmin _**integer_ **(_**encoding,video_**)**
           Set min video quantizer scale (VBR). Must be included between -1 and 69, default value is
           2.

       **qmax _**integer_ **(_**encoding,video_**)**
           Set  max video quantizer scale (VBR). Must be included between -1 and 1024, default value
           is 31.

       **qdiff _**integer_ **(_**encoding,video_**)**
           Set max difference between the quantizer scale (VBR).

       **bf _**integer_ **(_**encoding,video_**)**
           Set max number of B frames between non-B-frames.

           Must be an integer between -1 and 16. 0 means that B-frames are disabled. If a  value  of
           -1 is used, it will choose an automatic value depending on the encoder.

           Default value is 0.

       **b_qfactor _**float_ **(_**encoding,video_**)**
           Set qp factor between P and B frames.

       **codec_tag _**integer_
       **bug _**flags_ **(_**decoding,video_**)**
           Workaround not auto detected encoder bugs.

           Possible values:

           **autodetect**
           **xvid_ilace**
               Xvid interlacing bug (autodetected if fourcc==XVIX)

           **ump4**
               (autodetected if fourcc==UMP4)

           **no_padding**
               padding bug (autodetected)

           **amv**
           **qpel_chroma**
           **std_qpel**
               old standard qpel (autodetected per fourcc/version)

           **qpel_chroma2**
           **direct_blocksize**
               direct-qpel-blocksize bug (autodetected per fourcc/version)

           **edge**
               edge padding bug (autodetected per fourcc/version)

           **hpel_chroma**
           **dc_clip**
           **ms  **Workaround various bugs in microsoft broken decoders.

           **trunc**
               trancated frames

       **strict _**integer_ **(_**decoding/encoding,audio,video_**)**
           Specify how strictly to follow the standards.

           Possible values:

           **very**
               strictly conform to an older more strict version of the spec or reference software

           **strict**
               strictly conform to all the things in the spec no matter what consequences

           **normal**
           **unofficial**
               allow unofficial extensions

           **experimental**
               allow   non   standardized  experimental  things,  experimental  (unfinished/work  in
               progress/not well tested) decoders and encoders.   Note:  experimental  decoders  can
               pose a security risk, do not use this for decoding untrusted input.

       **b_qoffset _**float_ **(_**encoding,video_**)**
           Set QP offset between P and B frames.

       **err_detect _**flags_ **(_**decoding,audio,video_**)**
           Set error detection flags.

           Possible values:

           **crccheck**
               verify embedded CRCs

           **bitstream**
               detect bitstream specification deviations

           **buffer**
               detect improper bitstream length

           **explode**
               abort decoding on minor error detection

           **ignore_err**
               ignore decoding errors, and continue decoding.  This is useful if you want to analyze
               the  content  of  a video and thus want everything to be decoded no matter what. This
               option will not result in a video that is pleasing to watch in case of errors.

           **careful**
               consider things that violate the spec and have not been seen in the wild as errors

           **compliant**
               consider all spec non compliancies as errors

           **aggressive**
               consider things that a sane encoder should not do as an error

       **has_b_frames _**integer_
       **block_align _**integer_
       **rc_override_count _**integer_
       **maxrate _**integer_ **(_**encoding,audio,video_**)**
           Set max bitrate tolerance (in bits/s). Requires bufsize to be set.

       **minrate _**integer_ **(_**encoding,audio,video_**)**
           Set min bitrate tolerance (in bits/s). Most useful in setting up a CBR encode. It  is  of
           little use elsewise.

       **bufsize _**integer_ **(_**encoding,audio,video_**)**
           Set ratecontrol buffer size (in bits).

       **i_qfactor _**float_ **(_**encoding,video_**)**
           Set QP factor between P and I frames.

       **i_qoffset _**float_ **(_**encoding,video_**)**
           Set QP offset between P and I frames.

       **dct _**integer_ **(_**encoding,video_**)**
           Set DCT algorithm.

           Possible values:

           **auto**
               autoselect a good one (default)

           **fastint**
               fast integer

           **int **accurate integer

           **mmx**
           **altivec**
           **faan**
               floating point AAN DCT

       **lumi_mask _**float_ **(_**encoding,video_**)**
           Compress bright areas stronger than medium ones.

       **tcplx_mask _**float_ **(_**encoding,video_**)**
           Set temporal complexity masking.

       **scplx_mask _**float_ **(_**encoding,video_**)**
           Set spatial complexity masking.

       **p_mask _**float_ **(_**encoding,video_**)**
           Set inter masking.

       **dark_mask _**float_ **(_**encoding,video_**)**
           Compress dark areas stronger than medium ones.

       **idct _**integer_ **(_**decoding/encoding,video_**)**
           Select IDCT implementation.

           Possible values:

           **auto**
           **int**
           **simple**
           **simplemmx**
           **simpleauto**
               Automatically pick a IDCT compatible with the simple one

           **arm**
           **altivec**
           **sh4**
           **simplearm**
           **simplearmv5te**
           **simplearmv6**
           **simpleneon**
           **xvid**
           **faani**
               floating point AAN IDCT

       **slice_count _**integer_
       **ec _**flags_ **(_**decoding,video_**)**
           Set error concealment strategy.

           Possible values:

           **guess_mvs**
               iterative motion vector (MV) search (slow)

           **deblock**
               use strong deblock filter for damaged MBs

           **favor_inter**
               favor predicting from the previous frame instead of the current

       **bits_per_coded_sample _**integer_
       **aspect _**rational_ _number_ **(_**encoding,video_**)**
           Set sample aspect ratio.

       **sar _**rational_ _number_ **(_**encoding,video_**)**
           Set sample aspect ratio. Alias to _aspect_.

       **debug _**flags_ **(_**decoding/encoding,audio,video,subtitles_**)**
           Print specific debug info.

           Possible values:

           **pict**
               picture info

           **rc  **rate control

           **bitstream**
           **mb_type**
               macroblock (MB) type

           **qp  **per-block quantization parameter (QP)

           **dct_coeff**
           **green_metadata**
               display complexity metadata for the upcoming frame, GoP or for a given duration.

           **skip**
           **startcode**
           **er  **error recognition

           **mmco**
               memory management control operations (H.264)

           **bugs**
           **buffers**
               picture buffer allocations

           **thread_ops**
               threading operations

           **nomc**
               skip motion compensation

       **cmp _**integer_ **(_**encoding,video_**)**
           Set full pel me compare function.

           Possible values:

           **sad **sum of absolute differences, fast (default)

           **sse **sum of squared errors

           **satd**
               sum of absolute Hadamard transformed differences

           **dct **sum of absolute DCT transformed differences

           **psnr**
               sum of squared quantization errors (avoid, low quality)

           **bit **number of bits needed for the block

           **rd  **rate distortion optimal, slow

           **zero**
               0

           **vsad**
               sum of absolute vertical differences

           **vsse**
               sum of squared vertical differences

           **nsse**
               noise preserving sum of squared differences

           **w53 **5/3 wavelet, only used in snow

           **w97 **9/7 wavelet, only used in snow

           **dctmax**
           **chroma**
       **subcmp _**integer_ **(_**encoding,video_**)**
           Set sub pel me compare function.

           Possible values:

           **sad **sum of absolute differences, fast (default)

           **sse **sum of squared errors

           **satd**
               sum of absolute Hadamard transformed differences

           **dct **sum of absolute DCT transformed differences

           **psnr**
               sum of squared quantization errors (avoid, low quality)

           **bit **number of bits needed for the block

           **rd  **rate distortion optimal, slow

           **zero**
               0

           **vsad**
               sum of absolute vertical differences

           **vsse**
               sum of squared vertical differences

           **nsse**
               noise preserving sum of squared differences

           **w53 **5/3 wavelet, only used in snow

           **w97 **9/7 wavelet, only used in snow

           **dctmax**
           **chroma**
       **mbcmp _**integer_ **(_**encoding,video_**)**
           Set macroblock compare function.

           Possible values:

           **sad **sum of absolute differences, fast (default)

           **sse **sum of squared errors

           **satd**
               sum of absolute Hadamard transformed differences

           **dct **sum of absolute DCT transformed differences

           **psnr**
               sum of squared quantization errors (avoid, low quality)

           **bit **number of bits needed for the block

           **rd  **rate distortion optimal, slow

           **zero**
               0

           **vsad**
               sum of absolute vertical differences

           **vsse**
               sum of squared vertical differences

           **nsse**
               noise preserving sum of squared differences

           **w53 **5/3 wavelet, only used in snow

           **w97 **9/7 wavelet, only used in snow

           **dctmax**
           **chroma**
       **ildctcmp _**integer_ **(_**encoding,video_**)**
           Set interlaced dct compare function.

           Possible values:

           **sad **sum of absolute differences, fast (default)

           **sse **sum of squared errors

           **satd**
               sum of absolute Hadamard transformed differences

           **dct **sum of absolute DCT transformed differences

           **psnr**
               sum of squared quantization errors (avoid, low quality)

           **bit **number of bits needed for the block

           **rd  **rate distortion optimal, slow

           **zero**
               0

           **vsad**
               sum of absolute vertical differences

           **vsse**
               sum of squared vertical differences

           **nsse**
               noise preserving sum of squared differences

           **w53 **5/3 wavelet, only used in snow

           **w97 **9/7 wavelet, only used in snow

           **dctmax**
           **chroma**
       **dia_size _**integer_ **(_**encoding,video_**)**
           Set diamond type & size for motion estimation.

           **(1024, INT_MAX)**
               full motion estimation(slowest)

           **(768, 1024]**
               umh motion estimation

           **(512, 768]**
               hex motion estimation

           **(256, 512]**
               l2s diamond motion estimation

           **[2,256]**
               var diamond motion estimation

           **(-1,  2)**
               small diamond motion estimation

           **-1  **funny diamond motion estimation

           **(INT_MIN, -1)**
               sab diamond motion estimation

       **last_pred _**integer_ **(_**encoding,video_**)**
           Set amount of motion predictors from the previous frame.

       **precmp _**integer_ **(_**encoding,video_**)**
           Set pre motion estimation compare function.

           Possible values:

           **sad **sum of absolute differences, fast (default)

           **sse **sum of squared errors

           **satd**
               sum of absolute Hadamard transformed differences

           **dct **sum of absolute DCT transformed differences

           **psnr**
               sum of squared quantization errors (avoid, low quality)

           **bit **number of bits needed for the block

           **rd  **rate distortion optimal, slow

           **zero**
               0

           **vsad**
               sum of absolute vertical differences

           **vsse**
               sum of squared vertical differences

           **nsse**
               noise preserving sum of squared differences

           **w53 **5/3 wavelet, only used in snow

           **w97 **9/7 wavelet, only used in snow

           **dctmax**
           **chroma**
       **pre_dia_size _**integer_ **(_**encoding,video_**)**
           Set diamond type & size for motion estimation pre-pass.

       **subq _**integer_ **(_**encoding,video_**)**
           Set sub pel motion estimation quality.

       **me_range _**integer_ **(_**encoding,video_**)**
           Set limit motion vectors range (1023 for DivX player).

       **global_quality _**integer_ **(_**encoding,audio,video_**)**
       **slice_flags _**integer_
       **mbd _**integer_ **(_**encoding,video_**)**
           Set macroblock decision algorithm (high quality mode).

           Possible values:

           **simple**
               use mbcmp (default)

           **bits**
               use fewest bits

           **rd  **use best rate distortion

       **rc_init_occupancy _**integer_ **(_**encoding,video_**)**
           Set number of bits which should be loaded into the rc buffer before decoding starts.

       **flags2 _**flags_ **(_**decoding/encoding,audio,video,subtitles_**)**
           Possible values:

           **fast**
               Allow non spec compliant speedup tricks.

           **noout**
               Skip bitstream encoding.

           **ignorecrop**
               Ignore cropping information from sps.

           **local_header**
               Place global headers at every keyframe instead of in extradata.

           **chunks**
               Frame data might be split into multiple chunks.

           **showall**
               Show all frames before the first keyframe.

           **export_mvs**
               Export  motion  vectors into frame side-data (see "AV_FRAME_DATA_MOTION_VECTORS") for
               codecs that support it. See also _doc/examples/export_mvs.c_.

           **skip_manual**
               Do not skip samples and export skip information as frame side data.

           **ass_ro_flush_noop**
               Do not reset ASS ReadOrder field on flush.

           **icc_profiles**
               Generate/parse embedded ICC profiles from/to colorimetry tags.

       **export_side_data _**flags_ **(_**decoding/encoding,audio,video,subtitles_**)**
           Possible values:

           **mvs **Export motion vectors into frame side-data (see  "AV_FRAME_DATA_MOTION_VECTORS")  for
               codecs that support it. See also _doc/examples/export_mvs.c_.

           **prft**
               Export encoder Producer Reference Time into packet side-data (see "AV_PKT_DATA_PRFT")
               for codecs that support it.

           **venc_params**
               Export    video    encoding    parameters    through    frame    side    data    (see
               "AV_FRAME_DATA_VIDEO_ENC_PARAMS") for codecs that support it. At present,  those  are
               H.264 and VP9.

           **film_grain**
               Export     film     grain     parameters     through    frame    side    data    (see
               "AV_FRAME_DATA_FILM_GRAIN_PARAMS").  Supported at present by AV1 decoders.

       **threads _**integer_ **(_**decoding/encoding,video_**)**
           Set the number of threads to be used, in case the selected codec implementation  supports
           multi-threading.

           Possible values:

           **auto, 0**
               automatically select the number of threads to set

           Default value is **auto**.

       **dc _**integer_ **(_**encoding,video_**)**
           Set intra_dc_precision.

       **nssew _**integer_ **(_**encoding,video_**)**
           Set nsse weight.

       **skip_top _**integer_ **(_**decoding,video_**)**
           Set number of macroblock rows at the top which are skipped.

       **skip_bottom _**integer_ **(_**decoding,video_**)**
           Set number of macroblock rows at the bottom which are skipped.

       **profile _**integer_ **(_**encoding,audio,video_**)**
           Set  encoder  codec  profile.  Default  value  is  **unknown**. Encoder specific profiles are
           documented in the relevant encoder documentation.

       **level _**integer_ **(_**encoding,audio,video_**)**
           Set the encoder level. This level depends on the specific codec, and might correspond  to
           the profile level. It is set by default to **unknown**.

           Possible values:

           **unknown**
       **lowres _**integer_ **(_**decoding,audio,video_**)**
           Decode at 1= 1/2, 2=1/4, 3=1/8 resolutions.

       **mblmin _**integer_ **(_**encoding,video_**)**
           Set min macroblock lagrange factor (VBR).

       **mblmax _**integer_ **(_**encoding,video_**)**
           Set max macroblock lagrange factor (VBR).

       **skip_loop_filter _**integer_ **(_**decoding,video_**)**
       **skip_idct        _**integer_ **(_**decoding,video_**)**
       **skip_frame       _**integer_ **(_**decoding,video_**)**
           Make decoder discard processing depending on the frame type selected by the option value.

           **skip_loop_filter  **skips  frame loop filtering, **skip_idct **skips frame IDCT/dequantization,
           **skip_frame **skips decoding.

           Possible values:

           **none**
               Discard no frame.

           **default**
               Discard useless frames like 0-sized frames.

           **noref**
               Discard all non-reference frames.

           **bidir**
               Discard all bidirectional frames.

           **nokey**
               Discard all frames excepts keyframes.

           **nointra**
               Discard all frames except I frames.

           **all **Discard all frames.

           Default value is **default**.

       **bidir_refine _**integer_ **(_**encoding,video_**)**
           Refine the two motion vectors used in bidirectional macroblocks.

       **keyint_min _**integer_ **(_**encoding,video_**)**
           Set minimum interval between IDR-frames.

       **refs _**integer_ **(_**encoding,video_**)**
           Set reference frames to consider for motion compensation.

       **trellis _**integer_ **(_**encoding,audio,video_**)**
           Set rate-distortion optimal quantization.

       **mv0_threshold _**integer_ **(_**encoding,video_**)**
       **compression_level _**integer_ **(_**encoding,audio,video_**)**
       **bits_per_raw_sample _**integer_
       **channel_layout _**integer_ **(_**decoding/encoding,audio_**)**
           Possible values:

       **request_channel_layout _**integer_ **(_**decoding,audio_**)**
           Possible values:

       **rc_max_vbv_use _**float_ **(_**encoding,video_**)**
       **rc_min_vbv_use _**float_ **(_**encoding,video_**)**
       **color_primaries _**integer_ **(_**decoding/encoding,video_**)**
           Possible values:

           **bt709**
               BT.709

           **bt470m**
               BT.470 M

           **bt470bg**
               BT.470 BG

           **smpte170m**
               SMPTE 170 M

           **smpte240m**
               SMPTE 240 M

           **film**
               Film

           **bt2020**
               BT.2020

           **smpte428**
           **smpte428_1**
               SMPTE ST 428-1

           **smpte431**
               SMPTE 431-2

           **smpte432**
               SMPTE 432-1

           **jedec-p22**
               JEDEC P22

       **color_trc _**integer_ **(_**decoding/encoding,video_**)**
           Possible values:

           **bt709**
               BT.709

           **gamma22**
               BT.470 M

           **gamma28**
               BT.470 BG

           **smpte170m**
               SMPTE 170 M

           **smpte240m**
               SMPTE 240 M

           **linear**
               Linear

           **log**
           **log100**
               Log

           **log_sqrt**
           **log316**
               Log square root

           **iec61966_2_4**
           **iec61966-2-4**
               IEC 61966-2-4

           **bt1361**
           **bt1361e**
               BT.1361

           **iec61966_2_1**
           **iec61966-2-1**
               IEC 61966-2-1

           **bt2020_10**
           **bt2020_10bit**
               BT.2020 - 10 bit

           **bt2020_12**
           **bt2020_12bit**
               BT.2020 - 12 bit

           **smpte2084**
               SMPTE ST 2084

           **smpte428**
           **smpte428_1**
               SMPTE ST 428-1

           **arib-std-b67**
               ARIB STD-B67

       **colorspace _**integer_ **(_**decoding/encoding,video_**)**
           Possible values:

           **rgb **RGB

           **bt709**
               BT.709

           **fcc **FCC

           **bt470bg**
               BT.470 BG

           **smpte170m**
               SMPTE 170 M

           **smpte240m**
               SMPTE 240 M

           **ycocg**
               YCOCG

           **bt2020nc**
           **bt2020_ncl**
               BT.2020 NCL

           **bt2020c**
           **bt2020_cl**
               BT.2020 CL

           **smpte2085**
               SMPTE 2085

           **chroma-derived-nc**
               Chroma-derived NCL

           **chroma-derived-c**
               Chroma-derived CL

           **ictcp**
               ICtCp

       **color_range _**integer_ **(_**decoding/encoding,video_**)**
           If used as input parameter, it serves as a hint to the  decoder,  which  color_range  the
           input has.  Possible values:

           **tv**
           **mpeg**
           **limited**
               MPEG (219*2^(n-8))

           **pc**
           **jpeg**
           **full**
               JPEG (2^n-1)

       **chroma_sample_location _**integer_ **(_**decoding/encoding,video_**)**
           Possible values:

           **left**
           **center**
           **topleft**
           **top**
           **bottomleft**
           **bottom**
       **log_level_offset _**integer_
           Set the log level offset.

       **slices _**integer_ **(_**encoding,video_**)**
           Number of slices, used in parallelized encoding.

       **thread_type _**flags_ **(_**decoding/encoding,video_**)**
           Select which multithreading methods to use.

           Use  of  **frame  **will  increase  decoding  delay by one frame per thread, so clients which
           cannot provide future frames should not use it.

           Possible values:

           **slice**
               Decode more than one part of a single frame at once.

               Multithreading using slices works only when the video was encoded with slices.

           **frame**
               Decode more than one frame at once.

           Default value is **slice+frame**.

       **audio_service_type _**integer_ **(_**encoding,audio_**)**
           Set audio service type.

           Possible values:

           **ma  **Main Audio Service

           **ef  **Effects

           **vi  **Visually Impaired

           **hi  **Hearing Impaired

           **di  **Dialogue

           **co  **Commentary

           **em  **Emergency

           **vo  **Voice Over

           **ka  **Karaoke

       **request_sample_fmt _**sample_fmt_ **(_**decoding,audio_**)**
           Set sample format audio decoders should prefer. Default value is "none".

       **pkt_timebase _**rational_ _number_
       **sub_charenc _**encoding_ **(_**decoding,subtitles_**)**
           Set the input subtitles character encoding.

       **field_order  _**field_order_ **(_**video_**)**
           Set/override the field order of the video.  Possible values:

           **progressive**
               Progressive video

           **tt  **Interlaced video, top field coded and displayed first

           **bb  **Interlaced video, bottom field coded and displayed first

           **tb  **Interlaced video, top coded first, bottom displayed first

           **bt  **Interlaced video, bottom coded first, top displayed first

       **skip_alpha _**bool_ **(_**decoding,video_**)**
           Set to 1 to disable processing alpha (transparency). This works like the **gray **flag in the
           **flags **option which skips chroma information instead of alpha. Default is 0.

       **codec_whitelist _**list_ **(_**input_**)**
           "," separated list of allowed decoders. By default all are allowed.

       **dump_separator _**string_ **(_**input_**)**
           Separator used to separate the fields printed  on  the  command  line  about  the  Stream
           parameters.  For example, to separate the fields with newlines and indentation:

                   ffprobe -dump_separator "
                                             "  -i ~/videos/matrixbench_mpeg2.mpg

       **max_pixels _**integer_ **(_**decoding/encoding,video_**)**
           Maximum  number  of  pixels  per  image.  This  value  can be used to avoid out of memory
           failures due to large images.

       **apply_cropping _**bool_ **(_**decoding,video_**)**
           Enable cropping if cropping parameters are multiples of the required  alignment  for  the
           left  and  top  parameters.  If  the  alignment is not met the cropping will be partially
           applied to maintain alignment.  Default is 1 (enabled).   Note:  The  required  alignment
           depends  on  if  "AV_CODEC_FLAG_UNALIGNED"  is set and the CPU. "AV_CODEC_FLAG_UNALIGNED"
           cannot be changed from the command line. Also hardware decoders will not  apply  left/top
           Cropping.

## DECODERS
       Decoders are configured elements in FFmpeg which allow the decoding of multimedia streams.

       When  you  configure  your  FFmpeg  build,  all  the supported native decoders are enabled by
       default.  Decoders  requiring  an  external  library  must  be  enabled  manually   via   the
       corresponding  "--enable-lib" option. You can list all available decoders using the configure
       option "--list-decoders".

       You can  disable  all  the  decoders  with  the  configure  option  "--disable-decoders"  and
       selectively  enable  /  disable single decoders with the options "--enable-decoder=_DECODER_" /
       "--disable-decoder=_DECODER_".

       The option "-decoders" of the ff* tools will display the list of enabled decoders.

## VIDEO DECODERS
       A description of some of the currently available video decoders follows.

### av1
       AOMedia Video 1 (AV1) decoder.

       _Options_

### operating_point
           Select an operating point of a scalable AV1 bitstream (0 - 31). Default is 0.

### rawvideo
       Raw video decoder.

       This decoder decodes rawvideo streams.

       _Options_

       **top _**top_field_first_
           Specify the assumed field type of the input video.

           **-1  **the video is assumed to be progressive (default)

           **0   **bottom-field-first is assumed

           **1   **top-field-first is assumed

### libdav1d
       dav1d AV1 decoder.

       libdav1d allows libavcodec to decode the AOMedia Video 1 (AV1) codec.  Requires the  presence
       of  the  libdav1d headers and library during configuration.  You need to explicitly configure
       the build with "--enable-libdav1d".

       _Options_

       The following options are supported by the libdav1d wrapper.

### framethreads
           Set amount of frame threads to use during decoding. The default value is 0  (autodetect).
           This  option is deprecated for libdav1d >= 1.0 and will be removed in the future. Use the
           option "max_frame_delay" and the global option "threads" instead.

### tilethreads
           Set amount of tile threads to use during decoding. The default value is  0  (autodetect).
           This  option is deprecated for libdav1d >= 1.0 and will be removed in the future. Use the
           global option "threads" instead.

### max_frame_delay
           Set max amount of frames the decoder may  buffer  internally.  The  default  value  is  0
           (autodetect).

### filmgrain
           Apply  film  grain  to  the  decoded  video  if present in the bitstream. Defaults to the
           internal default of the library.  This option is deprecated and will be  removed  in  the
           future.  See the global option "export_side_data" to export Film Grain parameters instead
           of applying it.

### oppoint
           Select an operating point of a scalable AV1 bitstream (0 - 31). Defaults to the  internal
           default of the library.

### alllayers
           Output all spatial layers of a scalable AV1 bitstream. The default value is false.

### libdavs2
       AVS2-P2/IEEE1857.4 video decoder wrapper.

       This decoder allows libavcodec to decode AVS2 streams with davs2 library.

### libuavs3d
       AVS3-P2/IEEE1857.10 video decoder.

       libuavs3d  allows  libavcodec to decode AVS3 streams.  Requires the presence of the libuavs3d
       headers and library during configuration.  You need to explicitly configure  the  build  with
       "--enable-libuavs3d".

       _Options_

       The following option is supported by the libuavs3d wrapper.

### frame_threads
           Set amount of frame threads to use during decoding. The default value is 0 (autodetect).

### QSV Decoders
       The family of Intel QuickSync Video decoders (VC1, MPEG-2, H.264, HEVC, JPEG/MJPEG, VP8, VP9,
       AV1).

       _Common_ _Options_

       The following options are supported by all qsv decoders.

       _async_depth_
           Internal parallelization depth, the higher the value the higher the latency.

       _gpu_copy_
           A GPU-accelerated copy between video and system memory

           **default**
           **on**
           **off**

       _HEVC_ _Options_

       Extra options for hevc_qsv.

       _load_plugin_
           A user plugin to load in an internal session

           **none**
           **hevc_sw**
           **hevc_hw**
       _load_plugins_
           A :-separate list of hexadecimal plugin UIDs to load in an internal session

### v210
       Uncompressed 4:2:2 10-bit decoder.

       _Options_

### custom_stride
           Set the line size of the v210 data in bytes. The default value is 0 (autodetect). You can
           use the special -1 value for a strideless v210 as seen in BOXX files.

## AUDIO DECODERS
       A description of some of the currently available audio decoders follows.

### ac3
       AC-3 audio decoder.

       This  decoder  implements  part  of  ATSC  A/52:2010  and  ETSI  TS  102  366, as well as the
       undocumented RealAudio 3 (a.k.a. dnet).

       _AC-3_ _Decoder_ _Options_

### -drc_scale _
           Dynamic Range Scale Factor. The factor to apply to dynamic range  values  from  the  AC-3
           stream.  This  factor  is  applied  exponentially.  The  default value is 1.  There are 3
           notable scale factor ranges:

           **drc_scale == 0**
               DRC disabled. Produces full range audio.

           **0 < drc_scale <= 1**
               DRC enabled.  Applies a fraction of the stream  DRC  value.   Audio  reproduction  is
               between full range and full compression.

           **drc_scale > 1**
               DRC  enabled.  Applies  drc_scale  asymmetrically.  Loud sounds are fully compressed.
               Soft sounds are enhanced.

### flac
       FLAC audio decoder.

       This decoder aims to implement the complete FLAC specification from Xiph.

       _FLAC_ _Decoder_ _options_

### -use_buggy_lpc
           The lavc FLAC encoder used to produce buggy  streams  with  high  lpc  values  (like  the
           default  value).  This option makes it possible to decode such streams correctly by using
           lavc's old buggy lpc logic for decoding.

### ffwavesynth
       Internal wave synthesizer.

       This decoder generates wave patterns according to predefined sequences.  Its  use  is  purely
       internal and the format of the data it accepts is not publicly documented.

### libcelt
       libcelt decoder wrapper.

       libcelt  allows libavcodec to decode the Xiph CELT ultra-low delay audio codec.  Requires the
       presence of the libcelt headers and library during configuration.   You  need  to  explicitly
       configure the build with "--enable-libcelt".

### libgsm
       libgsm decoder wrapper.

       libgsm  allows  libavcodec  to decode the GSM full rate audio codec. Requires the presence of
       the libgsm headers and library during configuration. You need  to  explicitly  configure  the
       build with "--enable-libgsm".

       This decoder supports both the ordinary GSM and the Microsoft variant.

### libilbc
       libilbc decoder wrapper.

       libilbc  allows  libavcodec  to  decode  the  Internet  Low Bitrate Codec (iLBC) audio codec.
       Requires the presence of the libilbc headers and library during configuration.  You  need  to
       explicitly configure the build with "--enable-libilbc".

       _Options_

       The following option is supported by the libilbc wrapper.

### enhance
           Enable  the  enhancement  of  the  decoded  audio  when  set to 1. The default value is 0
           (disabled).

### libopencore-amrnb
       libopencore-amrnb decoder wrapper.

       libopencore-amrnb allows libavcodec to decode the Adaptive Multi-Rate Narrowband audio codec.
       Using  it  requires  the  presence  of  the  libopencore-amrnb  headers  and  library  during
       configuration. You need to explicitly configure the build with "--enable-libopencore-amrnb".

       An FFmpeg native decoder for AMR-NB exists, so users can decode AMR-NB without this library.

### libopencore-amrwb
       libopencore-amrwb decoder wrapper.

       libopencore-amrwb  allows  libavcodec to decode the Adaptive Multi-Rate Wideband audio codec.
       Using  it  requires  the  presence  of  the  libopencore-amrwb  headers  and  library  during
       configuration. You need to explicitly configure the build with "--enable-libopencore-amrwb".

       An FFmpeg native decoder for AMR-WB exists, so users can decode AMR-WB without this library.

### libopus
       libopus decoder wrapper.

       libopus  allows libavcodec to decode the Opus Interactive Audio Codec.  Requires the presence
       of the libopus headers and library during configuration. You need to explicitly configure the
       build with "--enable-libopus".

       An FFmpeg native decoder for Opus exists, so users can decode Opus without this library.

## SUBTITLES DECODERS
### libaribb24
       ARIB STD-B24 caption decoder.

       Implements profiles A and C of the ARIB STD-B24 standard.

       _libaribb24_ _Decoder_ _Options_

### -aribb24-base-path _
           Sets the base  path  for  the  libaribb24  library.  This  is  utilized  for  reading  of
           configuration files (for custom unicode conversions), and for dumping of non-text symbols
           as images under that location.

           Unset by default.

### -aribb24-skip-ruby-text _
           Tells the decoder wrapper to skip text blocks that contain half-height ruby text.

           Enabled by default.

### libaribcaption
       Yet another ARIB STD-B24 caption decoder using external _libaribcaption_ library.

       Implements profiles A and C of the Japanse ARIB STD-B24 standard, Brazilian ABNT NBR 15606-1,
       and Philippines version of ISDB-T.

       Requires     the     presence     of     the     libaribcaption     headers    and    library
       (<**<https://github.com/xqq/libaribcaption>**>)  during  configuration.   You  need  to  explicitly
       configure  the  build  with "--enable-libaribcaption".  If both _libaribb24_ and _libaribcaption_
       are enabled, _libaribcaption_ decoder precedes.

       _libaribcaption_ _Decoder_ _Options_

### -sub_type _
           Specifies the format of the decoded subtitles.

           **bitmap**
               Graphical image.

           **ass **ASS formatted text.

           **text**
               Simple text based output without formatting.

           The default is _ass_ as same as _libaribb24_  decoder.   Some  present  players  (e.g.,  _mpv_)
           expect ASS format for ARIB caption.

### -caption_encoding _
           Specifies the encoding scheme of input subtitle text.

           **auto**
               Automatically detect text encoding (default).

           **jis **8bit-char JIS encoding defined in ARIB STD B24.  This encoding used in Japan for ISDB
               captions.

           **utf8**
               UTF-8  encoding  defined  in  ARIB STD B24.  This encoding is used in Philippines for
               ISDB-T captions.

           **latin**
               Latin character encoding defined in ABNT NBR 15606-1.  This encoding is used in South
               America for SBTVD / ISDB-Tb captions.

### -font _
           Specify comma-separated list of font family names to be  used  for  _bitmap_  or  _ass_  type
           subtitle rendering.  Only first font name is used for _ass_ type subtitle.

           If not specified, use internaly defined default font family.

### -ass_single_rect _
           ARIB  STD-B24  specifies  that some captions may be displayed at different positions at a
           time (multi-rectangle subtitle).   Since  some  players  (e.g.,  old  _mpv_)  can't  handle
           multiple   ASS  rectangles  in  a  single  AVSubtitle,  or  multiple  ASS  rectangles  of
           indeterminate duration with the same start timestamp, this option can change the behavior
           so that all the texts are displayed in a single ASS rectangle.

           The default is _false_.

           If your player cannot handle AVSubtitles with multiple ASS rectangles properly, set  this
           option to _true_ or define **ASS_SINGLE_RECT=1 **to change default behavior at compilation.

### -force_outline_text _
           Specify  whether  always  render  outline  text  for  all  characters  regardless  of the
           indication by charactor style.

           The default is _false_.

### -outline_width _
           Specify width for outline text, in dots (relative).

           The default is _1.5_.

### -ignore_background _
           Specify whether to ignore background color rendering.

           The default is _false_.

### -ignore_ruby _
           Specify whether to ignore rendering for ruby-like (furigana) characters.

           The default is _false_.

### -replace_drcs _
           Specify whether to render replaced DRCS characters as Unicode characters.

           The default is _true_.

### -replace_msz_ascii _
           Specify whether to replace MSZ (Middle Size; half  width)  fullwidth  alphanumerics  with
           halfwidth alphanumerics.

           The default is _true_.

### -replace_msz_japanese _
           Specify  whether to replace some MSZ (Middle Size; half width) fullwidth japanese special
           characters with halfwidth ones.

           The default is _true_.

### -replace_msz_glyph _
           Specify whether to replace MSZ (Middle Size; half width) characters with halfwidth glyphs
           if the fonts supports it.  This option works under FreeType or DirectWrite renderer  with
           Adobe-Japan1  compliant  fonts.   e.g., IBM Plex Sans JP, Morisawa BIZ UDGothic, Morisawa
           BIZ UDMincho, Yu Gothic, Yu Mincho, and Meiryo.

           The default is _true_.

### -canvas_size _
           Specify the resolution of the canvas to render subtitles  to;  usually,  this  should  be
           frame size of input video.  This only applies when "-subtitle_type" is set to _bitmap_.

           The libaribcaption decoder assumes input frame size for bitmap rendering as below:

           1.  PROFILE_A : 1440 x 1080 with SAR (PAR) 4:3

           2.  PROFILE_C : 320 x 180 with SAR (PAR) 1:1

           If  actual  frame  size  of  input  video  does  not match above assumption, the rendered
           captions may be distorted.  To make the captions undistorted, add  "-canvas_size"  option
           to specify actual input video size.

           Note  that  the  "-canvas_size"  option is not required for video with different size but
           same aspect ratio.  In such cases, the caption will be  stretched  or  shrunk  to  actual
           video  size  if  "-canvas_size"  option  is  not  specified.  If "-canvas_size" option is
           specified with different size, the caption will be stretched or shrunk as specified  size
           with calculated SAR.

       _libaribcaption_ _decoder_ _usage_ _examples_

       Display MPEG-TS file with ARIB subtitle by "ffplay" tool:

               ffplay -sub_type bitmap MPEG.TS

       Display MPEG-TS file with input frame size 1920x1080 by "ffplay" tool:

               ffplay -sub_type bitmap -canvas_size 1920x1080 MPEG.TS

       Embed ARIB subtitle in transcoded video:

               ffmpeg -sub_type bitmap -i src.m2t -filter_complex "[0:v][0:s]overlay" -vcodec h264 dest.mp4

### dvbsub
       _Options_

### compute_clut
           **-2  **Compute clut once if no matching CLUT is in the stream.

           **-1  **Compute clut if no matching CLUT is in the stream.

           **0   **Never compute CLUT

           **1   **Always compute CLUT and override the one provided in the stream.

### dvb_substream
           Selects the dvb substream, or all substreams if -1 which is default.

### dvdsub
       This codec decodes the bitmap subtitles used in DVDs; the same subtitles can also be found in
       VobSub file pairs and in some Matroska files.

       _Options_

### palette
           Specify  the  global  palette  used by the bitmaps. When stored in VobSub, the palette is
           normally specified in the index file; in Matroska, the palette is  stored  in  the  codec
           extra-data  in  the  same  format as in VobSub. In DVDs, the palette is stored in the IFO
           file, and therefore not available when reading from dumped VOB files.

           The format for this option is a string containing 16 24-bits hexadecimal numbers (without
           0x prefix) separated by commas, for example  "0d00ee,  ee450d,  101010,  eaeaea,  0ce60b,
           ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1, 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b".

### ifo_palette
           Specify the IFO file from which the global palette is obtained.  (experimental)

### forced_subs_only
           Only  decode  subtitle  entries  marked as forced. Some titles have forced and non-forced
           subtitles in the same track. Setting this flag to 1 will only keep the forced  subtitles.
           Default value is 0.

### libzvbi-teletext
       Libzvbi  allows  libavcodec to decode DVB teletext pages and DVB teletext subtitles. Requires
       the presence of the libzvbi headers and library during configuration. You need to  explicitly
       configure the build with "--enable-libzvbi".

       _Options_

### txt_page
           List  of  teletext page numbers to decode. Pages that do not match the specified list are
           dropped. You may use the special "*" string to match all pages, or  "subtitle"  to  match
           all subtitle pages.  Default value is *.

### txt_default_region
           Set  default  character set used for decoding, a value between 0 and 87 (see ETS 300 706,
           Section 15, Table 32). Default value is -1, which does not override the libzvbi  default.
           This  option  is  needed  for some legacy level 1.0 transmissions which cannot signal the
           proper charset.

### txt_chop_top
           Discards the top teletext line. Default value is 1.

### txt_format
           Specifies the format of the decoded subtitles.

           **bitmap**
               The default format, you should use this for teletext pages, because certain  graphics
               and colors cannot be expressed in simple text or even ASS.

           **text**
               Simple text based output without formatting.

           **ass **Formatted  ASS  output,  subtitle  pages and teletext pages are returned in different
               styles, subtitle pages are stripped down to text, but an effort is made to  keep  the
               text alignment and the formatting.

### txt_left
           X offset of generated bitmaps, default is 0.

### txt_top
           Y offset of generated bitmaps, default is 0.

### txt_chop_spaces
           Chops  leading  and trailing spaces and removes empty lines from the generated text. This
           option is useful for teletext based subtitles where empty spaces may be  present  at  the
           start or at the end of the lines or empty lines may be present between the subtitle lines
           because of double-sized teletext characters.  Default value is 1.

### txt_duration
           Sets  the  display  duration  of the decoded teletext pages or subtitles in milliseconds.
           Default value is -1 which means infinity or until the next subtitle event comes.

### txt_transparent
           Force transparent background of the generated teletext bitmaps. Default value is 0  which
           means an opaque background.

### txt_opacity
           Sets  the  opacity  (0-255) of the teletext background. If **txt_transparent **is not set, it
           only affects characters between a start box and an end box, typically subtitles.  Default
           value is 0 if **txt_transparent **is set, 255 otherwise.

## ENCODERS
       Encoders are configured elements in FFmpeg which allow the encoding of multimedia streams.

       When  you  configure  your  FFmpeg  build,  all  the supported native encoders are enabled by
       default.  Encoders  requiring  an  external  library  must  be  enabled  manually   via   the
       corresponding  "--enable-lib" option. You can list all available encoders using the configure
       option "--list-encoders".

       You can  disable  all  the  encoders  with  the  configure  option  "--disable-encoders"  and
       selectively  enable  /  disable single encoders with the options "--enable-encoder=_ENCODER_" /
       "--disable-encoder=_ENCODER_".

       The option "-encoders" of the ff* tools will display the list of enabled encoders.

## AUDIO ENCODERS
       A description of some of the currently available audio encoders follows.

### aac
       Advanced Audio Coding (AAC) encoder.

       This encoder is the default AAC encoder, natively implemented into FFmpeg.

       _Options_

       **b   **Set bit rate in bits/s. Setting this automatically  activates  constant  bit  rate  (CBR)
           mode. If this option is unspecified it is set to 128kbps.

       **q   **Set  quality for variable bit rate (VBR) mode. This option is valid only using the **ffmpeg**
           command-line tool. For library interface users, use **global_quality**.

### cutoff
           Set cutoff frequency. If unspecified will allow the encoder  to  dynamically  adjust  the
           cutoff to improve clarity on low bitrates.

### aac_coder
           Set AAC encoder coding method. Possible values:

           **twoloop**
               Two loop searching (TLS) method. This is the default method.

               This method first sets quantizers depending on band thresholds and then tries to find
               an  optimal combination by adding or subtracting a specific value from all quantizers
               and adjusting some individual quantizer a little.  Will tune itself based on  whether
               **aac_is**, **aac_ms **and **aac_pns **are enabled.

           **anmr**
               Average noise to mask ratio (ANMR) trellis-based solution.

               This  is  an  experimental  coder  which  currently produces a lower quality, is more
               unstable and is slower than the default twoloop coder but has  potential.   Currently
               has no support for the **aac_is **or **aac_pns **options.  Not currently recommended.

           **fast**
               Constant quantizer method.

               Uses  a  cheaper  version  of twoloop algorithm that doesn't try to do as many clever
               adjustments. Worse with low bitrates (less than  64kbps),  but  is  better  and  much
               faster at higher bitrates.

### aac_ms
           Sets  mid/side  coding  mode. The default value of "auto" will automatically use M/S with
           bands which will benefit from such coding. Can be forced for all bands  using  the  value
           "enable", which is mainly useful for debugging or disabled using "disable".

### aac_is
           Sets  intensity stereo coding tool usage. By default, it's enabled and will automatically
           toggle IS for similar pairs of stereo bands if it's  beneficial.   Can  be  disabled  for
           debugging by setting the value to "disable".

### aac_pns
           Uses  perceptual  noise  substitution  to  replace  low entropy high frequency bands with
           imperceptible white noise during the decoding process. By default, it's enabled, but  can
           be disabled for debugging purposes by using "disable".

### aac_tns
           Enables  the use of a multitap FIR filter which spans through the high frequency bands to
           hide quantization noise during the encoding process and is reverted by  the  decoder.  As
           well  as  decreasing unpleasant artifacts in the high range this also reduces the entropy
           in the high bands and allows for more bits to be used by the mid-low  bands.  By  default
           it's enabled but can be disabled for debugging by setting the option to "disable".

### aac_ltp
           Enables  the  use of the long term prediction extension which increases coding efficiency
           in very low bandwidth situations such as  encoding  of  voice  or  solo  piano  music  by
           extending  constant  harmonic peaks in bands throughout frames. This option is implied by
           profile:a aac_low and is incompatible with aac_pred.  Use  in  conjunction  with  **-ar  **to
           decrease the samplerate.

### aac_pred
           Enables the use of a more traditional style of prediction where the spectral coefficients
           transmitted are replaced by the difference of the current coefficients minus the previous
           "predicted"  coefficients.  In  theory and sometimes in practice this can improve quality
           for low to  mid  bitrate  audio.   This  option  implies  the  aac_main  profile  and  is
           incompatible with aac_ltp.

### profile
           Sets the encoding profile, possible values:

           **aac_low**
               The default, AAC "Low-complexity" profile. Is the most compatible and produces decent
               quality.

           **mpeg2_aac_low**
               Equivalent  to  "-profile:a  aac_low  -aac_pns  0". PNS was introduced with the MPEG4
               specifications.

           **aac_ltp**
               Long term prediction profile, is enabled by  and  will  enable  the  **aac_ltp  **option.
               Introduced in MPEG4.

           **aac_main**
               Main-type  prediction  profile,  is  enabled  by and will enable the **aac_pred **option.
               Introduced in MPEG2.

           If this option is unspecified it is set to **aac_low**.

### ac3 and ac3_fixed
       AC-3 audio encoders.

       These encoders implement part of ATSC  A/52:2010  and  ETSI  TS  102  366,  as  well  as  the
       undocumented RealAudio 3 (a.k.a. dnet).

       The  _ac3_  encoder uses floating-point math, while the _ac3_fixed_ encoder only uses fixed-point
       integer math. This does not mean that one is always faster, just that one or the other may be
       better suited to a particular system. The _ac3_fixed_ encoder is not the default codec for  any
       of  the  output  formats,  so  it  must  be  specified  explicitly  using the option "-acodec
       ac3_fixed" in order to use it.

       _AC-3_ _Metadata_

       The AC-3 metadata options are used to set parameters that describe the  audio,  but  in  most
       cases  do  not  affect  the  audio encoding itself. Some of the options do directly affect or
       influence the decoding and playback of the resulting bitstream, while  others  are  just  for
       informational  purposes.  A  few of the options will add bits to the output stream that could
       otherwise be used for audio data, and will thus affect the quality of the output. Those  will
       be indicated accordingly with a note in the option list below.

       These parameters are described in detail in several publicly-available documents.

       *<<**<http://www.atsc.org/cms/standards/a_52-2010.pdf>**>>
       *<<**<http://www.atsc.org/cms/standards/a_54a_with_corr_1.pdf>**>>
       *<<**<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/18_Metadata.Guide.pdf>**>>
       *<<**<http://www.dolby.com/uploadedFiles/zz-_Shared_Assets/English_PDFs/Professional/46_DDEncodingGuidelines.pdf>**>>

       Metadata Control Options

### -per_frame_metadata _
           Allow Per-Frame Metadata. Specifies if the encoder should check for changing metadata for
           each frame.

           **0   **The metadata values set at initialization will be used for every frame in the stream.
               (default)

           **1   **Metadata values can be changed before encoding each frame.

       Downmix Levels

### -center_mixlev _
           Center  Mix Level. The amount of gain the decoder should apply to the center channel when
           downmixing to stereo. This field will only be  written  to  the  bitstream  if  a  center
           channel is present. The value is specified as a scale factor. There are 3 valid values:

           **0.707**
               Apply -3dB gain

           **0.595**
               Apply -4.5dB gain (default)

           **0.500**
               Apply -6dB gain

### -surround_mixlev _
           Surround  Mix  Level.  The  amount  of  gain  the  decoder  should  apply to the surround
           channel(s) when downmixing to stereo. This field will only be written to the bitstream if
           one or more surround channels are present. The value is  specified  as  a  scale  factor.
           There are 3 valid values:

           **0.707**
               Apply -3dB gain

           **0.500**
               Apply -6dB gain (default)

           **0.000**
               Silence Surround Channel(s)

       Audio Production Information

       Audio  Production  Information  is  optional  information  describing the mixing environment.
       Either none or both of the fields are written to the bitstream.

### -mixing_level _
           Mixing Level. Specifies peak sound pressure level (SPL)  in  the  production  environment
           when  the  mix  was  mastered.  Valid  values  are  80  to  111, or -1 for unknown or not
           indicated. The default value is -1, but that value cannot be used if the Audio Production
           Information is written to the bitstream. Therefore, if the "room_type" option is not  the
           default value, the "mixing_level" option must not be -1.

### -room_type _
           Room  Type. Describes the equalization used during the final mixing session at the studio
           or on the dubbing stage. A large room is a  dubbing  stage  with  the  industry  standard
           X-curve equalization; a small room has flat equalization.  This field will not be written
           to  the  bitstream  if both the "mixing_level" option and the "room_type" option have the
           default values.

           **0**
           **notindicated**
               Not Indicated (default)

           **1**
           **large**
               Large Room

           **2**
           **small**
               Small Room

       Other Metadata Options

### -copyright _
           Copyright Indicator. Specifies whether a copyright exists for this audio.

           **0**
           **off **No Copyright Exists (default)

           **1**
           **on  **Copyright Exists

### -dialnorm _
           Dialogue Normalization. Indicates how far the average dialogue level of  the  program  is
           below  digital  100%  full scale (0 dBFS). This parameter determines a level shift during
           audio reproduction that sets the average volume of the dialogue to a  preset  level.  The
           goal is to match volume level between program sources. A value of -31dB will result in no
           volume  level  change,  relative  to  the source volume, during audio reproduction. Valid
           values are whole numbers in the range -31 to -1, with -31 being the default.

### -dsur_mode _
           Dolby Surround Mode. Specifies whether the stereo signal uses Dolby Surround (Pro Logic).
           This field will only be written to the bitstream if the audio  stream  is  stereo.  Using
           this option does **NOT **mean the encoder will actually apply Dolby Surround processing.

           **0**
           **notindicated**
               Not Indicated (default)

           **1**
           **off **Not Dolby Surround Encoded

           **2**
           **on  **Dolby Surround Encoded

### -original _
           Original  Bit  Stream Indicator. Specifies whether this audio is from the original source
           and not a copy.

           **0**
           **off **Not Original Source

           **1**
           **on  **Original Source (default)

       _Extended_ _Bitstream_ _Information_

       The extended bitstream options are part of the Alternate Bit Stream Syntax  as  specified  in
       Annex  D  of  the  A/52:2010 standard. It is grouped into 2 parts.  If any one parameter in a
       group is specified, all values in that group will  be  written  to  the  bitstream.   Default
       values are used for those that are written but have not been specified.  If the mixing levels
       are  written,  the  decoder  will  use  these  values  instead  of  the ones specified in the
       "center_mixlev" and "surround_mixlev" options if it supports the Alternate Bit Stream Syntax.

       Extended Bitstream Information - Part 1

### -dmix_mode _
           Preferred Stereo Downmix Mode. Allows the user to select either Lt/Rt (Dolby Surround) or
           Lo/Ro (normal stereo) as the preferred stereo downmix mode.

           **0**
           **notindicated**
               Not Indicated (default)

           **1**
           **ltrt**
               Lt/Rt Downmix Preferred

           **2**
           **loro**
               Lo/Ro Downmix Preferred

### -ltrt_cmixlev _
           Lt/Rt Center Mix Level. The amount of gain the decoder should apply to the center channel
           when downmixing to stereo in Lt/Rt mode.

           **1.414**
               Apply +3dB gain

           **1.189**
               Apply +1.5dB gain

           **1.000**
               Apply 0dB gain

           **0.841**
               Apply -1.5dB gain

           **0.707**
               Apply -3.0dB gain

           **0.595**
               Apply -4.5dB gain (default)

           **0.500**
               Apply -6.0dB gain

           **0.000**
               Silence Center Channel

### -ltrt_surmixlev _
           Lt/Rt Surround Mix Level. The amount of gain the decoder should  apply  to  the  surround
           channel(s) when downmixing to stereo in Lt/Rt mode.

           **0.841**
               Apply -1.5dB gain

           **0.707**
               Apply -3.0dB gain

           **0.595**
               Apply -4.5dB gain

           **0.500**
               Apply -6.0dB gain (default)

           **0.000**
               Silence Surround Channel(s)

### -loro_cmixlev _
           Lo/Ro Center Mix Level. The amount of gain the decoder should apply to the center channel
           when downmixing to stereo in Lo/Ro mode.

           **1.414**
               Apply +3dB gain

           **1.189**
               Apply +1.5dB gain

           **1.000**
               Apply 0dB gain

           **0.841**
               Apply -1.5dB gain

           **0.707**
               Apply -3.0dB gain

           **0.595**
               Apply -4.5dB gain (default)

           **0.500**
               Apply -6.0dB gain

           **0.000**
               Silence Center Channel

### -loro_surmixlev _
           Lo/Ro  Surround  Mix  Level.  The amount of gain the decoder should apply to the surround
           channel(s) when downmixing to stereo in Lo/Ro mode.

           **0.841**
               Apply -1.5dB gain

           **0.707**
               Apply -3.0dB gain

           **0.595**
               Apply -4.5dB gain

           **0.500**
               Apply -6.0dB gain (default)

           **0.000**
               Silence Surround Channel(s)

       Extended Bitstream Information - Part 2

### -dsurex_mode _
           Dolby Surround EX Mode. Indicates whether the stream uses Dolby Surround EX (7.1 matrixed
           to 5.1). Using this option does **NOT **mean the encoder will actually apply  Dolby  Surround
           EX processing.

           **0**
           **notindicated**
               Not Indicated (default)

           **1**
           **on  **Dolby Surround EX Off

           **2**
           **off **Dolby Surround EX On

### -dheadphone_mode _
           Dolby  Headphone Mode. Indicates whether the stream uses Dolby Headphone encoding (multi-
           channel matrixed to 2.0 for use with headphones). Using this option  does  **NOT  **mean  the
           encoder will actually apply Dolby Headphone processing.

           **0**
           **notindicated**
               Not Indicated (default)

           **1**
           **on  **Dolby Headphone Off

           **2**
           **off **Dolby Headphone On

### -ad_conv_type _
           A/D Converter Type. Indicates whether the audio has passed through HDCD A/D conversion.

           **0**
           **standard**
               Standard A/D Converter (default)

           **1**
           **hdcd**
               HDCD A/D Converter

       _Other_ _AC-3_ _Encoding_ _Options_

### -stereo_rematrixing _
           Stereo  Rematrixing.  Enables/Disables  use  of  rematrixing for stereo input. This is an
           optional AC-3 feature that increases  quality  by  selectively  encoding  the  left/right
           channels  as  mid/side.  This  option is enabled by default, and it is highly recommended
           that it be left as enabled except for testing purposes.

       **cutoff _**frequency_
           Set lowpass cutoff frequency. If unspecified, the encoder selects a default determined by
           various other encoding parameters.

       _Floating-Point-Only_ _AC-3_ _Encoding_ _Options_

       These options are only valid for the floating-point encoder and do not exist for  the  fixed-
       point encoder due to the corresponding features not being implemented in fixed-point.

### -channel_coupling _
           Enables/Disables  use  of  channel  coupling,  which  is  an  optional  AC-3 feature that
           increases quality by combining high frequency information from multiple channels  into  a
           single  channel. The per-channel high frequency information is sent with less accuracy in
           both the frequency and time  domains.  This  allows  more  bits  to  be  used  for  lower
           frequencies while preserving enough information to reconstruct the high frequencies. This
           option  is enabled by default for the floating-point encoder and should generally be left
           as enabled except for testing purposes or to increase encoding speed.

           **-1**
           **auto**
               Selected by Encoder (default)

           **0**
           **off **Disable Channel Coupling

           **1**
           **on  **Enable Channel Coupling

### -cpl_start_band _
           Coupling Start Band. Sets the channel coupling start band, from  1  to  15.  If  a  value
           higher  than  the  bandwidth  is used, it will be reduced to 1 less than the coupling end
           band. If _auto_ is used, the start band will be determined by the encoder based on the  bit
           rate,  sample  rate, and channel layout. This option has no effect if channel coupling is
           disabled.

           **-1**
           **auto**
               Selected by Encoder (default)

### flac
       FLAC (Free Lossless Audio Codec) Encoder

       _Options_

       The following options are supported by FFmpeg's flac encoder.

### compression_level
           Sets the compression level, which chooses defaults for many other options if they are not
           set explicitly. Valid values are from 0 to 12, 5 is the default.

### frame_size
           Sets the size of the frames in samples per channel.

### lpc_coeff_precision
           Sets the LPC coefficient precision, valid values are from 1 to 15, 15 is the default.

### lpc_type
           Sets the first stage LPC algorithm

           **none**
               LPC is not used

           **fixed**
               fixed LPC coefficients

           **levinson**
           **cholesky**
### lpc_passes
           Number of passes to use for Cholesky factorization during LPC analysis

### min_partition_order
           The minimum partition order

### max_partition_order
           The maximum partition order

### prediction_order_method
           **estimation**
           **2level**
           **4level**
           **8level**
           **search**
               Bruteforce search

           **log**
### ch_mode
           Channel mode

           **auto**
               The mode is chosen automatically for each frame

           **indep**
               Channels are independently coded

           **left_side**
           **right_side**
           **mid_side**
### exact_rice_parameters
           Chooses if rice parameters are calculated exactly or approximately.  if  set  to  1  then
           they  are  chosen  exactly,  which  slows the code down slightly and improves compression
           slightly.

### multi_dim_quant
           Multi Dimensional Quantization. If set to 1 then a 2nd stage  LPC  algorithm  is  applied
           after  the  first  stage  to  finetune  the coefficients. This is quite slow and slightly
           improves compression.

### opus
       Opus encoder.

       This is a native FFmpeg encoder for the Opus format. Currently its in  development  and  only
       implements  the  CELT part of the codec. Its quality is usually worse and at best is equal to
       the libopus encoder.

       _Options_

       **b   **Set bit rate in bits/s. If unspecified it uses the number of channels and the  layout  to
           make a good guess.

### opus_delay
           Sets the maximum delay in milliseconds. Lower delays than 20ms will very quickly decrease
           quality.

### libfdk_aac
       libfdk-aac AAC (Advanced Audio Coding) encoder wrapper.

       The libfdk-aac library is based on the Fraunhofer FDK AAC code from the Android project.

       Requires the presence of the libfdk-aac headers and library during configuration. You need to
       explicitly  configure  the build with "--enable-libfdk-aac". The library is also incompatible
       with GPL, so  if  you  allow  the  use  of  GPL,  you  should  configure  with  "--enable-gpl
       --enable-nonfree --enable-libfdk-aac".

       This encoder has support for the AAC-HE profiles.

       VBR  encoding,  enabled  through  the  **vbr **or **flags +qscale **options, is experimental and only
       works with some combinations of parameters.

       Support for encoding 7.1 audio is only available with libfdk-aac 0.1.3 or higher.

       For       more       information       see        the        fdk-aac        project        at
       <**<http://sourceforge.net/p/opencore-amr/fdk-aac/>**>.

       _Options_

       The following options are mapped on the shared FFmpeg codec options.

       **b   **Set  bit  rate in bits/s. If the bitrate is not explicitly specified, it is automatically
           set to a suitable value depending on the selected profile.

           In case VBR mode is enabled the option is ignored.

       **ar  **Set audio sampling rate (in Hz).

### channels
           Set the number of audio channels.

### flags +qscale
           Enable fixed quality, VBR (Variable Bit Rate) mode.  Note that VBR is implicitly  enabled
           when the **vbr **value is positive.

### cutoff
           Set  cutoff  frequency.  If  not  specified  (or explicitly set to 0) it will use a value
           automatically computed by the library. Default value is 0.

### profile
           Set audio profile.

           The following profiles are recognized:

           **aac_low**
               Low Complexity AAC (LC)

           **aac_he**
               High Efficiency AAC (HE-AAC)

           **aac_he_v2**
               High Efficiency AAC version 2 (HE-AACv2)

           **aac_ld**
               Low Delay AAC (LD)

           **aac_eld**
               Enhanced Low Delay AAC (ELD)

           If not specified it is set to **aac_low**.

       The following are private options of the libfdk_aac encoder.

### afterburner
           Enable afterburner feature if set to 1, disabled if set to 0. This improves  the  quality
           but also the required processing power.

           Default value is 1.

### eld_sbr
           Enable SBR (Spectral Band Replication) for ELD if set to 1, disabled if set to 0.

           Default value is 0.

### eld_v2
           Enable ELDv2 (LD-MPS extension for ELD stereo signals) for ELDv2 if set to 1, disabled if
           set to 0.

           Note       that       option       is       available      when      fdk-aac      version
           (AACENCODER_LIB_VL0.AACENCODER_LIB_VL1.AACENCODER_LIB_VL2) > (4.0.0).

           Default value is 0.

### signaling
           Set SBR/PS signaling style.

           It can assume one of the following values:

           **default**
               choose signaling implicitly (explicit hierarchical by  default,  implicit  if  global
               header is disabled)

           **implicit**
               implicit backwards compatible signaling

           **explicit_sbr**
               explicit SBR, implicit PS signaling

           **explicit_hierarchical**
               explicit hierarchical signaling

           Default value is **default**.

### latm
           Output LATM/LOAS encapsulated data if set to 1, disabled if set to 0.

           Default value is 0.

### header_period
           Set   StreamMuxConfig   and  PCE  repetition  period  (in  frames)  for  sending  in-band
           configuration buffers within LATM/LOAS transport layer.

           Must be a 16-bits non-negative integer.

           Default value is 0.

       **vbr **Set VBR mode, from 1 to 5. 1 is lowest quality  (though  still  pretty  good)  and  5  is
           highest quality. A value of 0 will disable VBR, and CBR (Constant Bit Rate) is enabled.

           Currently only the **aac_low **profile supports VBR encoding.

           VBR modes 1-5 correspond to roughly the following average bit rates:

           **1   **32 kbps/channel

           **2   **40 kbps/channel

           **3   **48-56 kbps/channel

           **4   **64 kbps/channel

           **5   **about 80-96 kbps/channel

           Default value is 0.

### frame_length
           Set  the  audio  frame  length  in  samples. Default value is the internal default of the
           library. Refer to the library's documentation for information about supported values.

       _Examples_

       •   Use **ffmpeg **to convert an audio file to VBR AAC in an M4A (MP4) container:

                   ffmpeg -i input.wav -codec:a libfdk_aac -vbr 3 output.m4a

       •   Use **ffmpeg **to convert an audio file to CBR 64k kbps AAC, using  the  High-Efficiency  AAC
           profile:

                   ffmpeg -i input.wav -c:a libfdk_aac -profile:a aac_he -b:a 64k output.m4a

### libmp3lame
       LAME (Lame Ain't an MP3 Encoder) MP3 encoder wrapper.

       Requires the presence of the libmp3lame headers and library during configuration. You need to
       explicitly configure the build with "--enable-libmp3lame".

       See **libshine **for a fixed-point MP3 encoder, although with a lower quality.

       _Options_

       The  following  options  are  supported by the libmp3lame wrapper. The **lame**-equivalent of the
       options are listed in parentheses.

       **b (_**-b_**)**
           Set bitrate expressed  in  bits/s  for  CBR  or  ABR.  LAME  "bitrate"  is  expressed  in
           kilobits/s.

       **q (_**-V_**)**
           Set constant quality setting for VBR. This option is valid only using the **ffmpeg **command-
           line tool. For library interface users, use **global_quality**.

       **compression_level (_**-q_**)**
           Set  algorithm  quality.  Valid  arguments  are integers in the 0-9 range, with 0 meaning
           highest quality but slowest, and 9 meaning fastest while producing the worst quality.

       **cutoff (_**--lowpass_**)**
           Set lowpass cutoff frequency. If unspecified, the encoder dynamically adjusts the cutoff.

### reservoir
           Enable use of bit reservoir when set to 1. Default value is 1. LAME has this  enabled  by
           default, but can be overridden by use **--nores **option.

       **joint_stereo (_**-m_ _j_**)**
           Enable  the  encoder  to  use  (on  a frame by frame basis) either L/R stereo or mid/side
           stereo. Default value is 1.

       **abr (_**--abr_**)**
           Enable the encoder to use ABR when set to 1. The **lame  --abr  **sets  the  target  bitrate,
           while this options only tells FFmpeg to use ABR still relies on **b **to set bitrate.

       **copyright (_**-c_**)**
           Set MPEG audio copyright flag when set to 1. The default value is 0 (disabled).

       **original (_**-o_**)**
           Set MPEG audio original flag when set to 1. The default value is 1 (enabled).

### libopencore-amrnb
       OpenCORE Adaptive Multi-Rate Narrowband encoder.

       Requires  the presence of the libopencore-amrnb headers and library during configuration. You
       need to explicitly configure the build with "--enable-libopencore-amrnb --enable-version3".

       This is a mono-only encoder. Officially it only supports 8000Hz  sample  rate,  but  you  can
       override it by setting **strict **to **unofficial **or lower.

       _Options_

       **b   **Set  bitrate  in  bits  per  second. Only the following bitrates are supported, otherwise
           libavcodec will round to the nearest valid bitrate.

           **4750**
           **5150**
           **5900**
           **6700**
           **7400**
           **7950**
           **10200**
           **12200**
       **dtx **Allow discontinuous transmission (generate comfort noise) when  set  to  1.  The  default
           value is 0 (disabled).

### libopus
       libopus Opus Interactive Audio Codec encoder wrapper.

       Requires  the  presence  of the libopus headers and library during configuration. You need to
       explicitly configure the build with "--enable-libopus".

       _Option_ _Mapping_

       Most libopus options are modelled after the **opusenc **utility from opus-tools. The following is
       an option mapping chart describing options  supported  by  the  libopus  wrapper,  and  their
       **opusenc**-equivalent in parentheses.

       **b (_**bitrate_**)**
           Set  the  bit  rate in bits/s.  FFmpeg's **b **option is expressed in bits/s, while **opusenc**'s
           **bitrate **in kilobits/s.

       **vbr (_**vbr_**, _**hard-cbr_**, and _**cvbr_**)**
           Set VBR mode. The FFmpeg **vbr **option has the following valid arguments, with  the  **opusenc**
           equivalent options in parentheses:

           **off (_**hard-cbr_**)**
               Use constant bit rate encoding.

           **on (_**vbr_**)**
               Use variable bit rate encoding (the default).

           **constrained (_**cvbr_**)**
               Use constrained variable bit rate encoding.

       **compression_level (_**comp_**)**
           Set  encoding algorithm complexity. Valid options are integers in the 0-10 range. 0 gives
           the fastest encodes but lower quality, while 10 gives the  highest  quality  but  slowest
           encoding. The default is 10.

       **frame_duration (_**framesize_**)**
           Set  maximum  frame  size,  or  duration of a frame in milliseconds. The argument must be
           exactly the following: 2.5, 5, 10, 20, 40, 60. Smaller frame sizes achieve lower  latency
           but  less  quality  at  a given bitrate.  Sizes greater than 20ms are only interesting at
           fairly low bitrates.  The default is 20ms.

       **packet_loss (_**expect-loss_**)**
           Set expected packet loss percentage. The default is 0.

       **fec (_**n/a_**)**
           Enable inband forward error correction. **packet_loss **must be non-zero to take advantage  -
           frequency  of  FEC  'side-data'  is  proportional  to  expected  packet loss.  Default is
           disabled.

### application (N.A.)
           Set intended application type. Valid options are listed below:

           **voip**
               Favor improved speech intelligibility.

           **audio**
               Favor faithfulness to the input (the default).

           **lowdelay**
               Restrict to only the lowest delay modes by disabling voice-optimized modes.

### cutoff (N.A.)
           Set cutoff bandwidth in Hz. The argument must be exactly  one  of  the  following:  4000,
           6000,  8000,  12000,  or  20000, corresponding to narrowband, mediumband, wideband, super
           wideband, and fullband respectively. The  default  is  0  (cutoff  disabled).  Note  that
           libopus  forces  a  wideband cutoff for bitrates < 15 kbps, unless CELT-only (**application**
           set to **lowdelay**) mode is used.

       **mapping_family (_**mapping_family_**)**
           Set channel mapping family to be used by the  encoder.  The  default  value  of  -1  uses
           mapping  family 0 for mono and stereo inputs, and mapping family 1 otherwise. The default
           also disables the surround  masking  and  LFE  bandwidth  optimzations  in  libopus,  and
           requires that the input contains 8 channels or fewer.

           Other  values  include  0  for mono and stereo, 1 for surround sound with masking and LFE
           bandwidth optimizations, and 255 for independent  streams  with  an  unspecified  channel
           layout.

### apply_phase_inv (N.A.) (requires libopus >= 1.2)
           If  set  to  0,  disables  the use of phase inversion for intensity stereo, improving the
           quality of mono downmixes, but slightly reducing normal stereo quality. The default is  1
           (phase inversion enabled).

### libshine
       Shine Fixed-Point MP3 encoder wrapper.

       Shine  is  a fixed-point MP3 encoder. It has a far better performance on platforms without an
       FPU, e.g. armel CPUs, and some phones and tablets.   However,  as  it  is  more  targeted  on
       performance  than  quality,  it  is  not on par with LAME and other production-grade encoders
       quality-wise. Also, according to the project's homepage, this encoder may not be free of bugs
       as the code was written a long time ago and the project was dead for at least 5 years.

       This encoder only supports stereo and mono input. This is also CBR-only.

       The     original     project     (last     updated     in     early     2007)      is      at
       <**<http://sourceforge.net/projects/libshine-fxp/>**>.  We  only  support  the  updated fork by the
       Savonet/Liquidsoap project at <**<https://github.com/savonet/shine>**>.

       Requires the presence of the libshine headers and library during configuration. You  need  to
       explicitly configure the build with "--enable-libshine".

       See also **libmp3lame**.

       _Options_

       The  following  options are supported by the libshine wrapper. The **shineenc**-equivalent of the
       options are listed in parentheses.

       **b (_**-b_**)**
           Set bitrate expressed in bits/s for CBR. **shineenc -b **option is expressed in kilobits/s.

### libtwolame
       TwoLAME MP2 encoder wrapper.

       Requires the presence of the libtwolame headers and library during configuration. You need to
       explicitly configure the build with "--enable-libtwolame".

       _Options_

       The following options are supported by the libtwolame wrapper. The **twolame**-equivalent options
       follow the FFmpeg ones and are in parentheses.

       **b (_**-b_**)**
           Set bitrate expressed in bits/s for CBR. **twolame b **option  is  expressed  in  kilobits/s.
           Default value is 128k.

       **q (_**-V_**)**
           Set  quality  for experimental VBR support. Maximum value range is from -50 to 50, useful
           range is from -10 to 10. The higher the value, the better the  quality.  This  option  is
           valid  only  using  the  **ffmpeg  **command-line  tool.  For  library  interface  users, use
           **global_quality**.

       **mode (_**--mode_**)**
           Set the mode of the resulting audio. Possible values:

           **auto**
               Choose mode automatically based on the input. This is the default.

           **stereo**
               Stereo

           **joint_stereo**
               Joint stereo

           **dual_channel**
               Dual channel

           **mono**
               Mono

       **psymodel (_**--psyc-mode_**)**
           Set psychoacoustic model to use in encoding. The argument must be an integer  between  -1
           and 4, inclusive. The higher the value, the better the quality. The default value is 3.

       **energy_levels (_**--energy_**)**
           Enable energy levels extensions when set to 1. The default value is 0 (disabled).

       **error_protection (_**--protect_**)**
           Enable CRC error protection when set to 1. The default value is 0 (disabled).

       **copyright (_**--copyright_**)**
           Set MPEG audio copyright flag when set to 1. The default value is 0 (disabled).

       **original (_**--original_**)**
           Set MPEG audio original flag when set to 1. The default value is 0 (disabled).

### libvo-amrwbenc
       VisualOn Adaptive Multi-Rate Wideband encoder.

       Requires  the  presence  of  the libvo-amrwbenc headers and library during configuration. You
       need to explicitly configure the build with "--enable-libvo-amrwbenc --enable-version3".

       This is a mono-only encoder. Officially it only supports 16000Hz sample  rate,  but  you  can
       override it by setting **strict **to **unofficial **or lower.

       _Options_

       **b   **Set  bitrate  in  bits/s. Only the following bitrates are supported, otherwise libavcodec
           will round to the nearest valid bitrate.

           **6600**
           **8850**
           **12650**
           **14250**
           **15850**
           **18250**
           **19850**
           **23050**
           **23850**
       **dtx **Allow discontinuous transmission (generate comfort noise) when  set  to  1.  The  default
           value is 0 (disabled).

### libvorbis
       libvorbis encoder wrapper.

       Requires  the presence of the libvorbisenc headers and library during configuration. You need
       to explicitly configure the build with "--enable-libvorbis".

       _Options_

       The following options are supported by the libvorbis wrapper. The  **oggenc**-equivalent  of  the
       options are listed in parentheses.

       To  get  a  more  accurate  and extensive documentation of the libvorbis options, consult the
       libvorbisenc's    and    **oggenc**'s     documentations.      See     <**<http://xiph.org/vorbis/>**>,
       <**<http://wiki.xiph.org/Vorbis-tools>**>, and [**oggenc**(1)](https://www.chedong.com/phpMan.php/man/oggenc/1/markdown).

       **b (_**-b_**)**
           Set bitrate expressed in bits/s for ABR. **oggenc -b **is expressed in kilobits/s.

       **q (_**-q_**)**
           Set  constant quality setting for VBR. The value should be a float number in the range of
           -1.0 to 10.0. The higher the value, the better the quality. The default value is **3.0**.

           This option is valid only using the **ffmpeg  **command-line  tool.   For  library  interface
           users, use **global_quality**.

       **cutoff (_**--advanced-encode-option_ _lowpass_frequency=N_**)**
           Set  cutoff  bandwidth  in  Hz,  a value of 0 disables cutoff. **oggenc**'s related option is
           expressed in kHz. The default value is **0 **(cutoff disabled).

       **minrate (_**-m_**)**
           Set minimum bitrate expressed in bits/s. **oggenc -m **is expressed in kilobits/s.

       **maxrate (_**-M_**)**
           Set maximum bitrate expressed in bits/s. **oggenc -M **is expressed in kilobits/s. This  only
           has effect on ABR mode.

       **iblock (_**--advanced-encode-option_ _impulse_noisetune=N_**)**
           Set noise floor bias for impulse blocks. The value is a float number from -15.0 to 0.0. A
           negative  bias  instructs  the  encoder  to  pay  special  attention  to the crispness of
           transients in the encoded audio. The tradeoff for better transient response is  a  higher
           bitrate.

### mjpeg
       Motion JPEG encoder.

       _Options_

### huffman
           Set the huffman encoding strategy. Possible values:

           **default**
               Use the default huffman tables. This is the default strategy.

           **optimal**
               Compute and use optimal huffman tables.

### wavpack
       WavPack lossless audio encoder.

       _Options_

       The equivalent options for **wavpack **command line utility are listed in parentheses.

       Shared options

       The  following  shared  options are effective for this encoder. Only special notes about this
       particular encoder will be documented here. For the general meaning of the options,  see  **the**
       **Codec Options chapter**.

       **frame_size (_**--blocksize_**)**
           For  this  encoder,  the  range  for  this  option  is between 128 and 131072. Default is
           automatically decided based on sample rate and number of channel.

           For the complete formula of calculating default, see _libavcodec/wavpackenc.c_.

       **compression_level (_**-f_**, _**-h_**, _**-hh_**, and _**-x_**)**

       Private options

       **joint_stereo (_**-j_**)**
           Set whether to enable joint stereo. Valid values are:

           **on (_**1_**)**
               Force mid/side audio encoding.

           **off (_**0_**)**
               Force left/right audio encoding.

           **auto**
               Let the encoder decide automatically.

### optimize_mono
           Set whether to enable optimization for mono. This option is only effective  for  non-mono
           streams. Available values:

           **on  **enabled

           **off **disabled

## VIDEO ENCODERS
       A description of some of the currently available video encoders follows.

### a64_multi, a64_multi5
       A64  /  Commodore  64  multicolor  charset  encoder.  "a64_multi5" is extended with 5th color
       (colram).

### Cinepak
       Cinepak aka CVID encoder.  Compatible with Windows 3.1 and vintage MacOS.

       _Options_

       **g _**integer_
           Keyframe interval.  A keyframe is inserted at least every "-g" frames, sometimes sooner.

       **q:v _**integer_
           Quality factor. Lower is better. Higher gives lower bitrate.  The following  table  lists
           bitrates when encoding akiyo_cif.y4m for various values of "-q:v" with "-g 100":

           **"-q:v 1" 1918 kb/s**
           **"-q:v 2" 1735 kb/s**
           **"-q:v 4" 1500 kb/s**
           **"-q:v 10" 1041 kb/s**
           **"-q:v 20" 826 kb/s**
           **"-q:v 40" 553 kb/s**
           **"-q:v 100" 394 kb/s**
           **"-q:v 200" 312 kb/s**
           **"-q:v 400" 266 kb/s**
           **"-q:v 1000" 237 kb/s**
       **max_extra_cb_iterations _**integer_
           Max extra codebook recalculation passes, more is better and slower.

       **skip_empty_cb _**boolean_
           Avoid wasting bytes, ignore vintage MacOS decoder.

       **max_strips _**integer_
       **min_strips _**integer_
           The minimum and maximum number of strips to use.  Wider range sometimes improves quality.
           More  strips is generally better quality but costs more bits.  Fewer strips tend to yield
           more keyframes.  Vintage compatible is 1..3.

       **strip_number_adaptivity _**integer_
           How much number of strips is allowed to change between  frames.   Higher  is  better  but
           slower.

   **GIF**
       GIF image/animation encoder.

       _Options_

       **gifflags _**integer_
           Sets the flags used for GIF encoding.

           **offsetting**
               Enables picture offsetting.

               Default is enabled.

           **transdiff**
               Enables transparency detection between frames.

               Default is enabled.

       **gifimage _**integer_
           Enables encoding one full GIF image per frame, rather than an animated GIF.

           Default value is **0**.

       **global_palette _**integer_
           Writes a palette to the global GIF header where feasible.

           If  disabled,  every  frame will always have a palette written, even if there is a global
           palette supplied.

           Default value is **1**.

### Hap
       Vidvox Hap video encoder.

       _Options_

       **format _**integer_
           Specifies the Hap format to encode.

           **hap**
           **hap_alpha**
           **hap_q**

           Default value is **hap**.

       **chunks _**integer_
           Specifies the number of chunks to split frames into,  between  1  and  64.  This  permits
           multithreaded decoding of large frames, potentially at the cost of data-rate. The encoder
           may modify this value to divide frames evenly.

           Default value is _1_.

       **compressor _**integer_
           Specifies  the  second-stage compressor to use. If set to **none**, **chunks **will be limited to
           1, as chunked uncompressed frames offer no benefit.

           **none**
           **snappy**

           Default value is **snappy**.

### jpeg2000
       The native jpeg 2000 encoder is lossy by default, the "-q:v" option can be used  to  set  the
       encoding quality. Lossless encoding can be selected with "-pred 1".

       _Options_

       **format _**integer_
           Can be set to either "j2k" or "jp2" (the default) that makes it possible to store non-rgb
           pix_fmts.

       **tile_width _**integer_
           Sets tile width. Range is 1 to 1073741824. Default is 256.

       **tile_height _**integer_
           Sets tile height. Range is 1 to 1073741824. Default is 256.

       **pred _**integer_
           Allows setting the discrete wavelet transform (DWT) type

           **dwt97int (Lossy)**
           **dwt53 (Lossless)**

           Default is "dwt97int"

       **sop _**boolean_
           Enable this to add SOP marker at the start of each packet. Disabled by default.

       **eph _**boolean_
           Enable this to add EPH marker at the end of each packet header. Disabled by default.

       **prog _**integer_
           Sets the progression order to be used by the encoder.  Possible values are:

           **lrcp**
           **rlcp**
           **rpcl**
           **pcrl**
           **cprl**

           Set to "lrcp" by default.

       **layer_rates _**string_
           By  default,  when this option is not used, compression is done using the quality metric.
           This option allows for compression using compression ratio.  The  compression  ratio  for
           each  level  could  be  specified.  The compression ratio of a layer "l" species the what
           ratio of total file size is contained in the first "l" layers.

           Example usage:

                   ffmpeg -i input.bmp -c:v jpeg2000 -layer_rates "100,10,1" output.j2k

           This would compress the image to contain 3 layers, where the data contained in the  first
           layer  would  be compressed by 1000 times, compressed by 100 in the first two layers, and
           shall contain all data while using all 3 layers.

### librav1e
       rav1e AV1 encoder wrapper.

       Requires the presence of the rav1e headers and library during  configuration.   You  need  to
       explicitly configure the build with "--enable-librav1e".

       _Options_

### qmax
           Sets the maximum quantizer to use when using bitrate mode.

### qmin
           Sets the minimum quantizer to use when using bitrate mode.

       **qp  **Uses quantizer mode to encode at the given quantizer (0-255).

### speed
           Selects the speed preset (0-10) to encode with.

### tiles
           Selects how many tiles to encode with.

### tile-rows
           Selects how many rows of tiles to encode with.

### tile-columns
           Selects how many columns of tiles to encode with.

### rav1e-params
           Set  rav1e options using a list of _key_=_value_ pairs separated by ":". See **rav1e --help **for
           a list of options.

           For example to specify librav1e encoding options with **-rav1e-params**:

                   ffmpeg -i input -c:v librav1e -b:v 500K -rav1e-params speed=5:low_latency=true output.mp4

### libaom-av1
       libaom AV1 encoder wrapper.

       Requires the presence of the libaom headers and library during configuration.   You  need  to
       explicitly configure the build with "--enable-libaom".

       _Options_

       The wrapper supports the following standard libavcodec options:

       **b   **Set  bitrate  target in bits/second.  By default this will use variable-bitrate mode.  If
           **maxrate **and **minrate **are also set to the same value  then  it  will  use  constant-bitrate
           mode, otherwise if **crf **is set as well then it will use constrained-quality mode.

### g keyint_min
           Set  key  frame placement.  The GOP size sets the maximum distance between key frames; if
           zero the output stream will be intra-only.  The minimum distance is ignored unless it  is
           the  same  as  the  GOP  size,  in  which  case  key frames will always appear at a fixed
           interval.  Not set by default, so without this option the  library  has  completely  free
           choice about where to place key frames.

### qmin qmax
           Set minimum/maximum quantisation values.  Valid range is from 0 to 63 (warning: this does
           not  match  the  quantiser  values  actually  used  by  AV1  - divide by four to map real
           quantiser values to this range).  Defaults to min/max (no constraint).

### minrate maxrate bufsize rc_init_occupancy
           Set rate control buffering parameters.  Not used if not set - defaults  to  unconstrained
           variable bitrate.

### threads
           Set  the  number  of threads to use while encoding.  This may require the **tiles **or **row-mt**
           options to also be set to actually use the specified number of threads fully. Defaults to
           the number of hardware threads supported by the host machine.

### profile
           Set the encoding profile.  Defaults to using the profile which matches the bit depth  and
           chroma subsampling of the input.

       The wrapper also has some specific options:

### cpu-used
           Set  the  quality/encoding  speed  tradeoff.   Valid range is from 0 to 8, higher numbers
           indicating greater speed and lower quality.  The default value is 1, which will  be  slow
           and high quality.

### auto-alt-ref
           Enable  use  of  alternate  reference  frames.   Defaults  to the internal default of the
           library.

       **arnr-max-frames (_**frames_**)**
           Set altref noise reduction max frame count. Default is -1.

       **arnr-strength (_**strength_**)**
           Set altref noise reduction filter strength. Range is -1 to 6. Default is -1.

       **aq-mode (_**aq-mode_**)**
           Set adaptive quantization mode. Possible values:

           **none (_**0_**)**
               Disabled.

           **variance (_**1_**)**
               Variance-based.

           **complexity (_**2_**)**
               Complexity-based.

           **cyclic (_**3_**)**
               Cyclic refresh.

       **tune (_**tune_**)**
           Set the distortion metric the encoder is tuned with. Default is "psnr".

           **psnr (_**0_**)**
           **ssim (_**1_**)**
### lag-in-frames
           Set the maximum number of frames which the encoder may keep in flight at any one time for
           lookahead purposes.  Defaults to the internal default of the library.

### error-resilience
           Enable error resilience features:

           **default**
               Improve resilience against losses of whole frames.

           Not enabled by default.

       **crf **Set the quality/size tradeoff for constant-quality (no bitrate target)  and  constrained-
           quality  (with  maximum  bitrate  target)  modes.  Valid range is 0 to 63, higher numbers
           indicating lower quality and smaller output size.  Only used if set; by default only  the
           bitrate target is used.

### static-thresh
           Set  a  change  threshold  on  blocks  below  which  they will be skipped by the encoder.
           Defined in arbitrary units as a nonnegative integer, defaulting to zero  (no  blocks  are
           skipped).

### drop-threshold
           Set  a  threshold  for  dropping  frames when close to rate control bounds.  Defined as a
           percentage of the target  buffer  -  when  the  rate  control  buffer  falls  below  this
           percentage,  frames  will be dropped until it has refilled above the threshold.  Defaults
           to zero (no frames are dropped).

       **denoise-noise-level (_**level_**)**
           Amount of noise to be removed for grain synthesis. Grain synthesis is  disabled  if  this
           option is not set or set to 0.

       **denoise-block-size (_**pixels_**)**
           Block size used for denoising for grain synthesis. If not set, AV1 codec uses the default
           value of 32.

       **undershoot-pct (_**pct_**)**
           Set  datarate  undershoot  (min)  percentage  of  the target bitrate. Range is -1 to 100.
           Default is -1.

       **overshoot-pct (_**pct_**)**
           Set datarate overshoot (max) percentage of the target  bitrate.  Range  is  -1  to  1000.
           Default is -1.

       **minsection-pct (_**pct_**)**
           Minimum  percentage  variation of the GOP bitrate from the target bitrate. If minsection-
           pct is not set, the  libaomenc  wrapper  computes  it  as  follows:  "(minrate  *  100  /
           bitrate)".  Range is -1 to 100. Default is -1 (unset).

       **maxsection-pct (_**pct_**)**
           Maximum  percentage  variation of the GOP bitrate from the target bitrate. If maxsection-
           pct is not set, the  libaomenc  wrapper  computes  it  as  follows:  "(maxrate  *  100  /
           bitrate)".  Range is -1 to 5000. Default is -1 (unset).

       **frame-parallel (_**boolean_**)**
           Enable frame parallel decodability features. Default is true.

### tiles
           Set  the  number  of  tiles  to  encode  the input video with, as columns x rows.  Larger
           numbers allow greater parallelism in both encoding and decoding, but may decrease  coding
           efficiency.   Defaults  to  the minimum number of tiles required by the size of the input
           video (this is 1x1 (that is, a single tile) for sizes up to and including 4K).

### tile-columns tile-rows
           Set the number of tiles as log2 of the number of tile rows  and  columns.   Provided  for
           compatibility with libvpx/VP9.

### row-mt (Requires libaom >= 1.0.0-759-g90a15f4f2)
           Enable row based multi-threading. Disabled by default.

       **enable-cdef (_**boolean_**)**
           Enable Constrained Directional Enhancement Filter. The libaom-av1 encoder enables CDEF by
           default.

       **enable-restoration (_**boolean_**)**
           Enable Loop Restoration Filter. Default is true for libaom-av1.

       **enable-global-motion (_**boolean_**)**
           Enable the use of global motion for block prediction. Default is true.

       **enable-intrabc (_**boolean_**)**
           Enable  block  copy  mode  for  intra  block  prediction.  This mode is useful for screen
           content. Default is true.

       **enable-rect-partitions (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable rectangular partitions. Default is true.

       **enable-1to4-partitions (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable 1:4/4:1 partitions. Default is true.

       **enable-ab-partitions (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable AB shape partitions. Default is true.

       **enable-angle-delta (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable angle delta intra prediction. Default is true.

       **enable-cfl-intra (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable chroma predicted from luma intra prediction. Default is true.

       **enable-filter-intra (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable filter intra predictor. Default is true.

       **enable-intra-edge-filter (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable intra edge filter. Default is true.

       **enable-smooth-intra (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable smooth intra prediction mode. Default is true.

       **enable-paeth-intra (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable paeth predictor in intra prediction. Default is true.

       **enable-palette (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable palette prediction mode. Default is true.

       **enable-flip-idtx (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable extended transform type, including FLIPADST_DCT, DCT_FLIPADST,  FLIPADST_FLIPADST,
           ADST_FLIPADST, FLIPADST_ADST, IDTX, V_DCT, H_DCT, V_ADST, H_ADST, V_FLIPADST, H_FLIPADST.
           Default is true.

       **enable-tx64 (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable 64-pt transform. Default is true.

       **reduced-tx-type-set (_**boolean_**) (Requires libaom >= v2.0.0)**
           Use reduced set of transform types. Default is false.

       **use-intra-dct-only (_**boolean_**) (Requires libaom >= v2.0.0)**
           Use DCT only for INTRA modes. Default is false.

       **use-inter-dct-only (_**boolean_**) (Requires libaom >= v2.0.0)**
           Use DCT only for INTER modes. Default is false.

       **use-intra-default-tx-only (_**boolean_**) (Requires libaom >= v2.0.0)**
           Use Default-transform only for INTRA modes. Default is false.

       **enable-ref-frame-mvs (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable temporal mv prediction. Default is true.

       **enable-reduced-reference-set (_**boolean_**) (Requires libaom >= v2.0.0)**
           Use reduced set of single and compound references. Default is false.

       **enable-obmc (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable obmc. Default is true.

       **enable-dual-filter (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable dual filter. Default is true.

       **enable-diff-wtd-comp (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable difference-weighted compound. Default is true.

       **enable-dist-wtd-comp (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable distance-weighted compound. Default is true.

       **enable-onesided-comp (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable one sided compound. Default is true.

       **enable-interinter-wedge (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable interinter wedge compound. Default is true.

       **enable-interintra-wedge (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable interintra wedge compound. Default is true.

       **enable-masked-comp (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable masked compound. Default is true.

       **enable-interintra-comp (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable interintra compound. Default is true.

       **enable-smooth-interintra (_**boolean_**) (Requires libaom >= v2.0.0)**
           Enable smooth interintra mode. Default is true.

### aom-params
           Set  libaom  options  using  a  list  of  _key_=_value_ pairs separated by ":". For a list of
           supported options, see **aomenc --help **under the section "AV1 Specific Options".

           For example to specify libaom encoding options with **-aom-params**:

                   ffmpeg -i input -c:v libaom-av1 -b:v 500K -aom-params tune=psnr:enable-tpl-model=1 output.mp4

### libsvtav1
       SVT-AV1 encoder wrapper.

       Requires the presence of the SVT-AV1 headers and library during configuration.  You  need  to
       explicitly configure the build with "--enable-libsvtav1".

       _Options_

### profile
           Set the encoding profile.

           **main**
           **high**
           **professional**
### level
           Set the operating point level. For example: '4.0'

### hielevel
           Set the Hierarchical prediction levels.

           **3level**
           **4level**
               This is the default.

### tier
           Set the operating point tier.

           **main**
               This is the default.

           **high**
### qmax
           Set the maximum quantizer to use when using a bitrate mode.

### qmin
           Set the minimum quantizer to use when using a bitrate mode.

       **crf **Constant rate factor value used in crf rate control mode (0-63).

       **qp  **Set the quantizer used in cqp rate control mode (0-63).

### sc_detection
           Enable scene change detection.

### la_depth
           Set number of frames to look ahead (0-120).

### preset
           Set the quality-speed tradeoff, in the range 0 to 13.  Higher values are faster but lower
           quality.

### tile_rows
           Set log2 of the number of rows of tiles to use (0-6).

### tile_columns
           Set log2 of the number of columns of tiles to use (0-4).

### svtav1-params
           Set  SVT-AV1  options  using  a list of _key_=_value_ pairs separated by ":". See the SVT-AV1
           encoder user guide for a list of accepted parameters.

### libjxl
       libjxl JPEG XL encoder wrapper.

       Requires the presence of the libjxl headers and library during  configuration.  You  need  to
       explicitly configure the build with "--enable-libjxl".

       _Options_

       The libjxl wrapper supports the following options:

### distance
           Set  the  target  Butteraugli  distance. This is a quality setting: lower distance yields
           higher  quality,  with  distance=1.0  roughly  comparable  to  libjpeg  Quality  90   for
           photographic  content.  Setting  distance=0.0 yields true lossless encoding. Valid values
           range between 0.0 and 15.0, and sane  values  rarely  exceed  5.0.  Setting  distance=0.1
           usually attains transparency for most input. The default is 1.0.

### effort
           Set  the  encoding  effort used. Higher effort values produce more consistent quality and
           usually produces a better quality/bpp curve, at the cost of more CPU time required. Valid
           values range from 1 to 9, and the default is 7.

### modular
           Force the encoder to use Modular mode instead of choosing automatically. The  default  is
           to  use  VarDCT for lossy encoding and Modular for lossless. VarDCT is generally superior
           to Modular for lossy encoding but does not support lossless encoding.

### libkvazaar
       Kvazaar H.265/HEVC encoder.

       Requires the presence of the libkvazaar headers and library during configuration. You need to
       explicitly configure the build with **--enable-libkvazaar**.

       _Options_

       **b   **Set target video bitrate in bit/s and enable rate control.

### kvazaar-params
           Set kvazaar parameters as a list of _name_=_value_ pairs separated by commas (,). See kvazaar
           documentation for a list of options.

### libopenh264
       Cisco libopenh264 H.264/MPEG-4 AVC encoder wrapper.

       This  encoder  requires  the  presence  of  the  libopenh264  headers  and   library   during
       configuration.  You  need  to explicitly configure the build with "--enable-libopenh264". The
       library is detected using **pkg-config**.

       For more information about the library see <**<http://www.openh264.org>**>.

       _Options_

       The following FFmpeg global options affect the configurations of the libopenh264 encoder.

       **b   **Set the bitrate (as a number of bits per second).

       **g   **Set the GOP size.

### maxrate
           Set the max bitrate (as a number of bits per second).

### flags +global_header
           Set global header in the bitstream.

### slices
           Set the number of slices, used in parallelized encoding. Default value is 0. This is only
           used when **slice_mode **is set to **fixed**.

### loopfilter
           Enable loop filter, if set to 1 (automatically enabled). To disable set a value of 0.

### profile
           Set  profile  restrictions.  If  set  to  the  value  of  **main  **enable  CABAC  (set   the
           "SEncParamExt.iEntropyCodingModeFlag" flag to 1).

### max_nal_size
           Set maximum NAL size in bytes.

### allow_skip_frames
           Allow skipping frames to hit the target bitrate if set to 1.

### libtheora
       libtheora Theora encoder wrapper.

       Requires  the presence of the libtheora headers and library during configuration. You need to
       explicitly configure the build with "--enable-libtheora".

       For more information about the libtheora project see <**<http://www.theora.org/>**>.

       _Options_

       The following global options are mapped  to  internal  libtheora  options  which  affect  the
       quality and the bitrate of the encoded stream.

       **b   **Set  the  video bitrate in bit/s for CBR (Constant Bit Rate) mode.  In case VBR (Variable
           Bit Rate) mode is enabled this option is ignored.

### flags
           Used to enable constant quality mode (VBR) encoding  through  the  **qscale  **flag,  and  to
           enable the "pass1" and "pass2" modes.

       **g   **Set the GOP size.

### global_quality
           Set the global quality as an integer in lambda units.

           Only relevant when VBR mode is enabled with "flags +qscale". The value is converted to QP
           units  by  dividing  it  by  "FF_QP2LAMBDA",  clipped  in  the  [0  - 10] range, and then
           multiplied by 6.3 to get a value in the native libtheora range  [0-63].  A  higher  value
           corresponds to a higher quality.

       **q   **Enable  VBR  mode  when  set to a non-negative value, and set constant quality value as a
           double floating point value in QP units.

           The value is clipped in the [0-10] range, and then multiplied by 6.3 to get  a  value  in
           the native libtheora range [0-63].

           This  option  is  valid  only  using  the **ffmpeg **command-line tool. For library interface
           users, use **global_quality**.

       _Examples_

       •   Set maximum constant quality (VBR) encoding with **ffmpeg**:

                   ffmpeg -i INPUT -codec:v libtheora -q:v 10 OUTPUT.ogg

       •   Use **ffmpeg **to convert a CBR 1000 kbps Theora video stream:

                   ffmpeg -i INPUT -codec:v libtheora -b:v 1000k OUTPUT.ogg

### libvpx
       VP8/VP9 format supported through libvpx.

       Requires the presence of the libvpx headers and library during configuration.   You  need  to
       explicitly configure the build with "--enable-libvpx".

       _Options_

       The  following  options are supported by the libvpx wrapper. The **vpxenc**-equivalent options or
       values are listed in parentheses for easy migration.

       To reduce the duplication  of  documentation,  only  the  private  options  and  some  others
       requiring  special  attention  are documented here. For the documentation of the undocumented
       generic options, see **the Codec Options chapter**.

       To get more documentation of the libvpx options, invoke the command **ffmpeg -h encoder=libvpx**,
       **ffmpeg -h encoder=libvpx-vp9 **or **vpxenc --help**. Further information is available in the libvpx
       API documentation.

       **b (_**target-bitrate_**)**
           Set bitrate in bits/s. Note that FFmpeg's **b **option is expressed in bits/s, while **vpxenc**'s
           **target-bitrate **is in kilobits/s.

       **g (_**kf-max-dist_**)**
       **keyint_min (_**kf-min-dist_**)**
       **qmin (_**min-q_**)**
           Minimum (Best Quality) Quantizer.

       **qmax (_**max-q_**)**
           Maximum (Worst Quality) Quantizer.  Can be changed per-frame.

       **bufsize (_**buf-sz_**, _**buf-optimal-sz_**)**
           Set  ratecontrol  buffer  size  (in  bits).  Note  **vpxenc**'s  options  are  specified   in
           milliseconds, the libvpx wrapper converts this value as follows: "buf-sz = bufsize * 1000
           / bitrate", "buf-optimal-sz = bufsize * 1000 / bitrate * 5 / 6".

       **rc_init_occupancy (_**buf-initial-sz_**)**
           Set number of bits which should be loaded into the rc buffer before decoding starts. Note
           **vpxenc**'s  option  is specified in milliseconds, the libvpx wrapper converts this value as
           follows: "rc_init_occupancy * 1000 / bitrate".

### undershoot-pct
           Set datarate undershoot (min) percentage of the target bitrate.

### overshoot-pct
           Set datarate overshoot (max) percentage of the target bitrate.

       **skip_threshold (_**drop-frame_**)**
       **qcomp (_**bias-pct_**)**
       **maxrate (_**maxsection-pct_**)**
           Set GOP max bitrate in bits/s. Note **vpxenc**'s option is specified as a percentage  of  the
           target  bitrate,  the  libvpx  wrapper  converts this value as follows: "(maxrate * 100 /
           bitrate)".

       **minrate (_**minsection-pct_**)**
           Set GOP min bitrate in bits/s. Note **vpxenc**'s option is specified as a percentage  of  the
           target  bitrate,  the  libvpx  wrapper  converts this value as follows: "(minrate * 100 /
           bitrate)".

       **minrate, maxrate, b _**end-usage=cbr_
           "(minrate == maxrate == bitrate)".

       **crf (_**end-usage=cq_**, _**cq-level_**)**
       **tune (_**tune_**)**
           **psnr (_**psnr_**)**
           **ssim (_**ssim_**)**
       **quality, deadline (_**deadline_**)**
           **best**
               Use best quality deadline. Poorly named and quite slow, this option should be avoided
               as it may give worse quality output than good.

           **good**
               Use good quality deadline. This is a good trade-off between speed  and  quality  when
               used with the **cpu-used **option.

           **realtime**
               Use realtime quality deadline.

       **speed, cpu-used (_**cpu-used_**)**
           Set  quality/speed  ratio  modifier.  Higher  values  speed  up the encode at the cost of
           quality.

       **nr (_**noise-sensitivity_**)**
### static-thresh
           Set a change threshold on blocks below which they will be skipped by the encoder.

       **slices (_**token-parts_**)**
           Note that FFmpeg's **slices **option gives the total number  of  partitions,  while  **vpxenc**'s
           **token-parts **is given as log2(partitions).

### max-intra-rate
           Set  maximum  I-frame  bitrate  as a percentage of the target bitrate. A value of 0 means
           unlimited.

### force_key_frames
           "VPX_EFLAG_FORCE_KF"

### Alternate reference frame related
           **auto-alt-ref**
               Enable use of alternate reference frames (2-pass only).  Values greater than 1 enable
               multi-layer alternate reference frames (VP9 only).

           **arnr-maxframes**
               Set altref noise reduction max frame count.

           **arnr-type**
               Set altref noise reduction filter type: backward, forward, centered.

           **arnr-strength**
               Set altref noise reduction filter strength.

           **rc-lookahead, lag-in-frames (_**lag-in-frames_**)**
               Set number of frames to look ahead for frametype and ratecontrol.

           **min-gf-interval**
               Set minimum golden/alternate reference frame interval (VP9 only).

### error-resilient
           Enable error resiliency features.

       **sharpness _**integer_
           Increase sharpness at the expense of lower PSNR.  The valid range is [0, 7].

### ts-parameters
           Sets the temporal scalability configuration using a :-separated list of key=value  pairs.
           For example, to specify temporal scalability parameters with "ffmpeg":

                   ffmpeg -i INPUT -c:v libvpx -ts-parameters ts_number_layers=3:\
                   ts_target_bitrate=250,500,1000:ts_rate_decimator=4,2,1:\
                   ts_periodicity=4:ts_layer_id=0,2,1,2:ts_layering_mode=3 OUTPUT

           Below  is  a  brief  explanation  of  each  of  the  parameters,  please refer to "struct
           vpx_codec_enc_cfg" in "vpx/vpx_encoder.h" for more details.

           **ts_number_layers**
               Number of temporal coding layers.

           **ts_target_bitrate**
               Target bitrate for each temporal layer (in kbps).  (bitrate should  be  inclusive  of
               the lower temporal layer).

           **ts_rate_decimator**
               Frame rate decimation factor for each temporal layer.

           **ts_periodicity**
               Length of the sequence defining frame temporal layer membership.

           **ts_layer_id**
               Template defining the membership of frames to temporal layers.

           **ts_layering_mode**
               (optional)  Selecting  the  temporal  structure  from  a  set of pre-defined temporal
               layering modes.  Currently supports the following options.

               **0   **No temporal layering flags are provided internally, relies on flags being  passed
                   in using "metadata" field in "AVFrame" with following keys.

                   **vp8-flags**
                       Sets the flags passed into the encoder to indicate the referencing scheme for
                       the    current    frame.     Refer    to   function   "vpx_codec_encode"   in
                       "vpx/vpx_encoder.h" for more details.

                   **temporal_id**
                       Explicitly sets the temporal id of the current frame to encode.

               **2   **Two temporal layers. 0-1...

               **3   **Three temporal layers. 0-2-1-2...; with single reference frame.

               **4   **Same as option "3", except there is a dependency between the two temporal layer 2
                   frames within the temporal period.

### VP9-specific options
           **lossless**
               Enable lossless mode.

           **tile-columns**
               Set number of tile columns to use. Note this  is  given  as  log2(tile_columns).  For
               example, 8 tile columns would be requested by setting the **tile-columns **option to 3.

           **tile-rows**
               Set  number of tile rows to use. Note this is given as log2(tile_rows).  For example,
               4 tile rows would be requested by setting the **tile-rows **option to 2.

           **frame-parallel**
               Enable frame parallel decodability features.

           **aq-mode**
               Set adaptive quantization mode (0: off  (default),  1:  variance  2:  complexity,  3:
               cyclic refresh, 4: equator360).

           **colorspace _**color-space_
               Set   input   color  space.  The  VP9  bitstream  supports  signaling  the  following
               colorspaces:

               **rgb sRGB**
               **bt709 bt709**
               **unspecified unknown**
               **bt470bg bt601**
               **smpte170m smpte170**
               **smpte240m smpte240**
               **bt2020_ncl bt2020**
           **row-mt _**boolean_
               Enable row based multi-threading.

           **tune-content**
               Set content type: default (0), screen (1), film (2).

           **corpus-complexity**
               Corpus VBR mode is a variant  of  standard  VBR  where  the  complexity  distribution
               midpoint is passed in rather than calculated for a specific clip or chunk.

               The valid range is [0, 10000]. 0 (default) uses standard VBR.

           **enable-tpl _**boolean_
               Enable temporal dependency model.

           **ref-frame-config**
               Using  per-frame  metadata, set members of the structure "vpx_svc_ref_frame_config_t"
               in "vpx/vp8cx.h" to fine-control referencing schemes  and  frame  buffer  management.
               Use a :-separated list of key=value pairs.  For example,

                       av_dict_set(&av_frame->metadata, "ref-frame-config", \
                       "rfc_update_buffer_slot=7:rfc_lst_fb_idx=0:rfc_gld_fb_idx=1:rfc_alt_fb_idx=2:rfc_reference_last=0:rfc_reference_golden=0:rfc_reference_alt_ref=0");

               **rfc_update_buffer_slot**
                   Indicates the buffer slot number to update

               **rfc_update_last**
                   Indicates whether to update the LAST frame

               **rfc_update_golden**
                   Indicates whether to update GOLDEN frame

               **rfc_update_alt_ref**
                   Indicates whether to update ALT_REF frame

               **rfc_lst_fb_idx**
                   LAST frame buffer index

               **rfc_gld_fb_idx**
                   GOLDEN frame buffer index

               **rfc_alt_fb_idx**
                   ALT_REF frame buffer index

               **rfc_reference_last**
                   Indicates whether to reference LAST frame

               **rfc_reference_golden**
                   Indicates whether to reference GOLDEN frame

               **rfc_reference_alt_ref**
                   Indicates whether to reference ALT_REF frame

               **rfc_reference_duration**
                   Indicates frame duration

       For more information about libvpx see: <**<http://www.webmproject.org/>**>

### libwebp
       libwebp WebP Image encoder wrapper

       libwebp  is  Google's  official  encoder  for  WebP  images. It can encode in either lossy or
       lossless mode. Lossy images are essentially a wrapper around a VP8 frame. Lossless images are
       a separate codec developed by Google.

       _Pixel_ _Format_

       Currently, libwebp only supports YUV420 for lossy and RGB for lossless due to limitations  of
       the  format  and libwebp. Alpha is supported for either mode.  Because of API limitations, if
       RGB is passed in when encoding lossy or YUV is passed in for  encoding  lossless,  the  pixel
       format will automatically be converted using functions from libwebp. This is not ideal and is
       done only for convenience.

       _Options_

### -lossless _
           Enables/Disables use of lossless mode. Default is 0.

### -compression_level _
           For  lossy,  this  is  a  quality/speed tradeoff. Higher values give better quality for a
           given size at the cost of increased encoding time. For lossless,  this  is  a  size/speed
           tradeoff.  Higher  values  give smaller size at the cost of increased encoding time. More
           specifically, it controls the number of extra algorithms and compression tools used,  and
           varies  the  combination  of  these tools. This maps to the _method_ option in libwebp. The
           valid range is 0 to 6.  Default is 4.

### -quality _
           For lossy encoding, this controls image quality. For lossless encoding, this controls the
           effort and time spent in compression.  Range is 0 to 100. Default is 75.

### -preset _
           Configuration preset. This does some automatic settings based on the general type of  the
           image.

           **none**
               Do not use a preset.

           **default**
               Use the encoder default.

           **picture**
               Digital picture, like portrait, inner shot

           **photo**
               Outdoor photograph, with natural lighting

           **drawing**
               Hand or line drawing, with high-contrast details

           **icon**
               Small-sized colorful images

           **text**
               Text-like

### libx264, libx264rgb
       x264 H.264/MPEG-4 AVC encoder wrapper.

       This  encoder  requires the presence of the libx264 headers and library during configuration.
       You need to explicitly configure the build with "--enable-libx264".

       libx264 supports an impressive number of features, including 8x8  and  4x4  adaptive  spatial
       transform,  adaptive  B-frame  placement,  CAVLC/CABAC  entropy  coding, interlacing (MBAFF),
       lossless mode, psy optimizations for detail retention (adaptive  quantization,  psy-RD,  psy-
       trellis).

       Many  libx264 encoder options are mapped to FFmpeg global codec options, while unique encoder
       options are provided through private  options.  Additionally  the  **x264opts  **and  **x264-params**
       private  options  allows  one  to  pass a list of key=value tuples as accepted by the libx264
       "x264_param_parse" function.

       The x264 project website is at <**<http://www.videolan.org/developers/x264.html>**>.

       The libx264rgb encoder is the same as libx264, except it accepts packed RGB pixel formats  as
       input instead of YUV.

       _Supported_ _Pixel_ _Formats_

       x264  supports  8-  to  10-bit  color  spaces.  The  exact  bit depth is controlled at x264's
       configure time.

       _Options_

       The following options are supported by the libx264 wrapper. The  **x264**-equivalent  options  or
       values are listed in parentheses for easy migration.

       To  reduce  the  duplication  of  documentation,  only  the  private  options and some others
       requiring special attention are documented here. For the documentation  of  the  undocumented
       generic options, see **the Codec Options chapter**.

       To get a more accurate and extensive documentation of the libx264 options, invoke the command
       **x264 --fullhelp **or consult the libx264 documentation.

       **b (_**bitrate_**)**
           Set  bitrate  in bits/s. Note that FFmpeg's **b **option is expressed in bits/s, while **x264**'s
           **bitrate **is in kilobits/s.

       **bf (_**bframes_**)**
       **g (_**keyint_**)**
       **qmin (_**qpmin_**)**
           Minimum quantizer scale.

       **qmax (_**qpmax_**)**
           Maximum quantizer scale.

       **qdiff (_**qpstep_**)**
           Maximum difference between quantizer scales.

       **qblur (_**qblur_**)**
           Quantizer curve blur

       **qcomp (_**qcomp_**)**
           Quantizer curve compression factor

       **refs (_**ref_**)**
           Number of reference frames each P-frame can use. The range is from _0-16_.

       **level (_**level_**)**
           Set the "x264_param_t.i_level_idc" value in case the value is  positive,  it  is  ignored
           otherwise.

           This   value   can   be   set  using  the  "AVCodecContext"  API  (e.g.  by  setting  the
           "AVCodecContext"  value  directly),  and  is  specified  as  an  integer  mapped   on   a
           corresponding  level  (e.g. the value 31 maps to H.264 level IDC "3.1", as defined in the
           "x264_levels" table). It is ignored when set to a non positive value.

           Alternatively  it  can  be  set  as  a  private  option,  overriding  the  value  set  in
           "AVCodecContext",  and  in  this case must be specified as the level IDC identifier (e.g.
           "3.1"), as defined by H.264 Annex A.

       **sc_threshold (_**scenecut_**)**
           Sets the threshold for the scene change detection.

       **trellis (_**trellis_**)**
           Performs Trellis quantization to increase efficiency. Enabled by default.

       **nr  (_**nr_**)**
       **me_range (_**merange_**)**
           Maximum range of the motion search in pixels.

       **me_method (_**me_**)**
           Set motion estimation method. Possible values in the decreasing order of speed:

           **dia (_**dia_**)**
           **epzs (_**dia_**)**
               Diamond search with radius 1 (fastest). **epzs **is an alias for **dia**.

           **hex (_**hex_**)**
               Hexagonal search with radius 2.

           **umh (_**umh_**)**
               Uneven multi-hexagon search.

           **esa (_**esa_**)**
               Exhaustive search.

           **tesa (_**tesa_**)**
               Hadamard exhaustive search (slowest).

### forced-idr
           Normally, when forcing a I-frame type, the encoder can select any type of  I-frame.  This
           option forces it to choose an IDR-frame.

       **subq (_**subme_**)**
           Sub-pixel motion estimation method.

       **b_strategy (_**b-adapt_**)**
           Adaptive B-frame placement decision algorithm. Use only on first-pass.

       **keyint_min (_**min-keyint_**)**
           Minimum GOP size.

### coder
           Set entropy encoder. Possible values:

           **ac  **Enable CABAC.

           **vlc **Enable  CAVLC  and  disable  CABAC. It generates the same effect as **x264**'s **--no-cabac**
               option.

       **cmp **Set full pixel motion estimation comparison algorithm. Possible values:

           **chroma**
               Enable chroma in motion estimation.

           **sad **Ignore  chroma  in  motion  estimation.  It  generates  the  same  effect  as  **x264**'s
               **--no-chroma-me **option.

       **threads (_**threads_**)**
           Number of encoding threads.

### thread_type
           Set multithreading technique. Possible values:

           **slice**
               Slice-based  multithreading.  It generates the same effect as **x264**'s **--sliced-threads**
               option.

           **frame**
               Frame-based multithreading.

### flags
           Set encoding flags. It can be used to disable closed GOP and enable open GOP  by  setting
           it to "-cgop". The result is similar to the behavior of **x264**'s **--open-gop **option.

       **rc_init_occupancy (_**vbv-init_**)**
       **preset (_**preset_**)**
           Set the encoding preset.

       **tune (_**tune_**)**
           Set tuning of the encoding params.

       **profile (_**profile_**)**
           Set profile restrictions.

### fastfirstpass
           Enable  fast  settings when encoding first pass, when set to 1. When set to 0, it has the
           same effect of **x264**'s **--slow-firstpass **option.

       **crf (_**crf_**)**
           Set the quality for constant quality mode.

       **crf_max (_**crf-max_**)**
           In CRF mode, prevents VBV from lowering quality beyond this point.

       **qp (_**qp_**)**
           Set constant quantization rate control method parameter.

       **aq-mode (_**aq-mode_**)**
           Set AQ method. Possible values:

           **none (_**0_**)**
               Disabled.

           **variance (_**1_**)**
               Variance AQ (complexity mask).

           **autovariance (_**2_**)**
               Auto-variance AQ (experimental).

       **aq-strength (_**aq-strength_**)**
           Set AQ strength, reduce blocking and blurring in flat and textured areas.

       **psy **Use psychovisual optimizations when set to 1. When set to 0, it has the  same  effect  as
           **x264**'s **--no-psy **option.

       **psy-rd  (_**psy-rd_**)**
           Set strength of psychovisual optimization, in _psy-rd_:_psy-trellis_ format.

       **rc-lookahead (_**rc-lookahead_**)**
           Set number of frames to look ahead for frametype and ratecontrol.

### weightb
           Enable  weighted  prediction  for  B-frames when set to 1. When set to 0, it has the same
           effect as **x264**'s **--no-weightb **option.

       **weightp (_**weightp_**)**
           Set weighted prediction method for P-frames. Possible values:

           **none (_**0_**)**
               Disabled

           **simple (_**1_**)**
               Enable only weighted refs

           **smart (_**2_**)**
               Enable both weighted refs and duplicates

       **ssim (_**ssim_**)**
           Enable calculation and printing SSIM stats after the encoding.

       **intra-refresh (_**intra-refresh_**)**
           Enable the use of Periodic Intra Refresh instead of IDR frames when set to 1.

       **avcintra-class (_**class_**)**
           Configure the encoder to generate AVC-Intra.  Valid values are 50,100 and 200

       **bluray-compat (_**bluray-compat_**)**
           Configure the encoder to be compatible with the bluray standard.  It is a  shorthand  for
           setting "bluray-compat=1 force-cfr=1".

       **b-bias (_**b-bias_**)**
           Set the influence on how often B-frames are used.

       **b-pyramid (_**b-pyramid_**)**
           Set method for keeping of some B-frames as references. Possible values:

           **none (_**none_**)**
               Disabled.

           **strict (_**strict_**)**
               Strictly hierarchical pyramid.

           **normal (_**normal_**)**
               Non-strict (not Blu-ray compatible).

### mixed-refs
           Enable the use of one reference per partition, as opposed to one reference per macroblock
           when set to 1. When set to 0, it has the same effect as **x264**'s **--no-mixed-refs **option.

### 8x8dct
           Enable adaptive spatial transform (high profile 8x8 transform) when set to 1. When set to
           0, it has the same effect as **x264**'s **--no-8x8dct **option.

### fast-pskip
           Enable  early  SKIP  detection  on P-frames when set to 1. When set to 0, it has the same
           effect as **x264**'s **--no-fast-pskip **option.

       **aud (_**aud_**)**
           Enable use of access unit delimiters when set to 1.

### mbtree
           Enable use macroblock tree ratecontrol when set to 1. When set to  0,  it  has  the  same
           effect as **x264**'s **--no-mbtree **option.

       **deblock (_**deblock_**)**
           Set loop filter parameters, in _alpha_:_beta_ form.

       **cplxblur (_**cplxblur_**)**
           Set fluctuations reduction in QP (before curve compression).

       **partitions (_**partitions_**)**
           Set partitions to consider as a comma-separated list of. Possible values in the list:

           **p8x8**
               8x8 P-frame partition.

           **p4x4**
               4x4 P-frame partition.

           **b8x8**
               4x4 B-frame partition.

           **i8x8**
               8x8 I-frame partition.

           **i4x4**
               4x4  I-frame  partition.   (Enabling  **p4x4 **requires **p8x8 **to be enabled. Enabling **i8x8**
               requires adaptive spatial transform (**8x8dct **option) to be enabled.)

           **none (_**none_**)**
               Do not consider any partitions.

           **all (_**all_**)**
               Consider every partition.

       **direct-pred (_**direct_**)**
           Set direct MV prediction mode. Possible values:

           **none (_**none_**)**
               Disable MV prediction.

           **spatial (_**spatial_**)**
               Enable spatial predicting.

           **temporal (_**temporal_**)**
               Enable temporal predicting.

           **auto (_**auto_**)**
               Automatically decided.

       **slice-max-size (_**slice-max-size_**)**
           Set the limit of the size of each slice in bytes. If not specified but RTP  payload  size
           (**ps**) is specified, that is used.

       **stats (_**stats_**)**
           Set the file name for multi-pass stats.

       **nal-hrd (_**nal-hrd_**)**
           Set signal HRD information (requires **vbv-bufsize **to be set).  Possible values:

           **none (_**none_**)**
               Disable HRD information signaling.

           **vbr (_**vbr_**)**
               Variable bit rate.

           **cbr (_**cbr_**)**
               Constant bit rate (not allowed in MP4 container).

### x264opts (N.A.)
           Set any x264 option, see **x264 --fullhelp **for a list.

           Argument  is  a  list of _key_=_value_ couples separated by ":". In _filter_ and _psy-rd_ options
           that use ":" as a separator themselves, use "," instead. They accept  it  as  well  since
           long ago but this is kept undocumented for some reason.

           For example to specify libx264 encoding options with **ffmpeg**:

                   ffmpeg -i foo.mpg -c:v libx264 -x264opts keyint=123:min-keyint=20 -an out.mkv

       **a53cc _**boolean_
           Import  closed  captions  (which  must  be ATSC compatible format) into output.  Only the
           mpeg2 and h264 decoders provide these. Default is 1 (on).

       **udu_sei _**boolean_
           Import user data unregistered SEI if available into output. Default is 0 (off).

       **mb_info _**boolean_
           Set mb_info data through AVFrameSideData, only useful when used from the API. Default  is
           0 (off).

### x264-params (N.A.)
           Override the x264 configuration using a :-separated list of key=value parameters.

           This option is functionally the same as the **x264opts**, but is duplicated for compatibility
           with the Libav fork.

           For example to specify libx264 encoding options with **ffmpeg**:

                   ffmpeg -i INPUT -c:v libx264 -x264-params level=30:bframes=0:weightp=0:\
                   cabac=0:ref=1:vbv-maxrate=768:vbv-bufsize=2000:analyse=all:me=umh:\
                   no-fast-pskip=1:subq=6:8x8dct=0:trellis=0 OUTPUT

       Encoding  ffpresets  for  common  usages  are  provided  so they can be used with the general
       presets system (e.g. passing the **pre **option).

### libx265
       x265 H.265/HEVC encoder wrapper.

       This encoder requires the presence of the libx265 headers and library  during  configuration.
       You need to explicitly configure the build with **--enable-libx265**.

       _Options_

       **b   **Sets target video bitrate.

       **bf**
       **g   **Set the GOP size.

### keyint_min
           Minimum GOP size.

### refs
           Number of reference frames each P-frame can use. The range is from _1-16_.

### preset
           Set the x265 preset.

### tune
           Set the x265 tune parameter.

### profile
           Set profile restrictions.

       **crf **Set the quality for constant quality mode.

       **qp  **Set constant quantization rate control method parameter.

### qmin
           Minimum quantizer scale.

### qmax
           Maximum quantizer scale.

### qdiff
           Maximum difference between quantizer scales.

### qblur
           Quantizer curve blur

### qcomp
           Quantizer curve compression factor

### i_qfactor
### b_qfactor
### forced-idr
           Normally,  when  forcing a I-frame type, the encoder can select any type of I-frame. This
           option forces it to choose an IDR-frame.

       **udu_sei _**boolean_
           Import user data unregistered SEI if available into output. Default is 0 (off).

### x265-params
           Set x265 options using a list of _key_=_value_ couples separated by ":". See **x265 --help  **for
           a list of options.

           For example to specify libx265 encoding options with **-x265-params**:

                   ffmpeg -i input -c:v libx265 -x265-params crf=26:psy-rd=1 output.mp4

### libxavs2
       xavs2 AVS2-P2/IEEE1857.4 encoder wrapper.

       This  encoder requires the presence of the libxavs2 headers and library during configuration.
       You need to explicitly configure the build with **--enable-libxavs2**.

       The following standard libavcodec options are used:

       •   **b **/ **bit_rate**

       •   **g **/ **gop_size**

       •   **bf **/ **max_b_frames**

       The encoder also has its own specific options:

       _Options_

### lcu_row_threads
           Set the number of parallel threads for rows from 1 to 8 (default 5).

### initial_qp
           Set the xavs2 quantization parameter from 1 to 63 (default 34). This is used to  set  the
           initial qp for the first frame.

       **qp  **Set  the  xavs2 quantization parameter from 1 to 63 (default 34). This is used to set the
           qp value under constant-QP mode.

### max_qp
           Set the max qp for rate control from 1 to 63 (default 55).

### min_qp
           Set the min qp for rate control from 1 to 63 (default 20).

### speed_level
           Set the Speed level from 0 to 9 (default 0). Higher is better but slower.

### log_level
           Set the log level from -1 to 3 (default 0). -1: none, 0: error, 1: warning, 2:  info,  3:
           debug.

### xavs2-params
           Set xavs2 options using a list of _key_=_value_ couples separated by ":".

           For example to specify libxavs2 encoding options with **-xavs2-params**:

                   ffmpeg -i input -c:v libxavs2 -xavs2-params RdoqLevel=0 output.avs2

### libxvid
       Xvid MPEG-4 Part 2 encoder wrapper.

       This   encoder   requires  the  presence  of  the  libxvidcore  headers  and  library  during
       configuration.  You  need  to  explicitly  configure   the   build   with   "--enable-libxvid
       --enable-gpl".

       The  native  "mpeg4"  encoder  supports the MPEG-4 Part 2 format, so users can encode to this
       format without this library.

       _Options_

       The following options are supported by the libxvid wrapper. Some of the following options are
       listed but are not documented, and correspond to shared codec options. See **the Codec  Options**
       **chapter **for their documentation. The other shared options which are not listed have no effect
       for the libxvid encoder.

       **b**
       **g**
### qmin
### qmax
### mpeg_quant
### threads
       **bf**
### b_qfactor
### b_qoffset
### flags
           Set specific encoding flags. Possible values:

           **mv4 **Use four motion vector by macroblock.

           **aic **Enable high quality AC prediction.

           **gray**
               Only encode grayscale.

           **gmc **Enable the use of global motion compensation (GMC).

           **qpel**
               Enable quarter-pixel motion compensation.

           **cgop**
               Enable closed GOP.

           **global_header**
               Place global headers in extradata instead of every keyframe.

### trellis
### me_quality
           Set  motion  estimation  quality  level. Possible values in decreasing order of speed and
           increasing order of quality:

           **0   **Use no motion estimation (default).

           **1, 2**
               Enable advanced diamond zonal search for 16x16 blocks and half-pixel  refinement  for
               16x16 blocks.

           **3, 4**
               Enable  all of the things described above, plus advanced diamond zonal search for 8x8
               blocks and half-pixel refinement for 8x8 blocks, also  enable  motion  estimation  on
               chroma planes for P and B-frames.

           **5, 6**
               Enable all of the things described above, plus extended 16x16 and 8x8 blocks search.

       **mbd **Set macroblock decision algorithm. Possible values in the increasing order of quality:

           **simple**
               Use macroblock comparing function algorithm (default).

           **bits**
               Enable  rate  distortion-based  half  pixel  and  quarter  pixel refinement for 16x16
               blocks.

           **rd  **Enable all of the things described above, plus rate distortion-based half  pixel  and
               quarter  pixel  refinement  for  8x8  blocks,  and rate distortion-based search using
               square pattern.

### lumi_aq
           Enable lumi masking adaptive quantization when set to 1. Default is 0 (disabled).

### variance_aq
           Enable variance adaptive quantization when set to 1. Default is 0 (disabled).

           When combined with **lumi_aq**, the resulting quality will not be better than any of the  two
           specified  individually.  In  other words, the resulting quality will be the worse one of
           the two effects.

### ssim
           Set structural similarity (SSIM) displaying method. Possible values:

           **off **Disable displaying of SSIM information.

           **avg **Output average SSIM at the end of encoding to  stdout.  The  format  of  showing  the
               average SSIM is:

                       Average SSIM: %f

               For  users  who  are not familiar with C, %f means a float number, or a decimal (e.g.
               0.939232).

           **frame**
               Output both per-frame SSIM data during encoding  and  average  SSIM  at  the  end  of
               encoding to stdout. The format of per-frame information is:

                              SSIM: avg: %1.3f min: %1.3f max: %1.3f

               For users who are not familiar with C, %1.3f means a float number rounded to 3 digits
               after the dot (e.g. 0.932).

### ssim_acc
           Set  SSIM accuracy. Valid options are integers within the range of 0-4, while 0 gives the
           most accurate result and 4 computes the fastest.

### MediaFoundation
       This provides wrappers to encoders (both audio and video) in the  MediaFoundation  framework.
       It  can  access  both SW and HW encoders.  Video encoders can take input in either of nv12 or
       yuv420p form (some encoders support both, some support only either - in practice, nv12 is the
       safer choice, especially among HW encoders).

### Microsoft RLE
       Microsoft RLE aka MSRLE encoder.  Only 8-bit palette mode supported.  Compatible with Windows
       3.1 and Windows 95.

       _Options_

       **g _**integer_
           Keyframe interval.  A keyframe is inserted at least every "-g" frames, sometimes sooner.

### mpeg2
       MPEG-2 video encoder.

       _Options_

### profile
           Select the mpeg2 profile to encode:

           **422**
           **high**
           **ss  **Spatially Scalable

           **snr **SNR Scalable

           **main**
           **simple**
### level
           Select the mpeg2 level to encode:

           **high**
           **high1440**
           **main**
           **low**
       **seq_disp_ext _**integer_
           Specifies if the encoder should write a sequence_display_extension to the output.

           **-1**
           **auto**
               Decide automatically to write it or not (this is the default) by checking if the data
               to be written is different from the default or unspecified values.

           **0**
           **never**
               Never write it.

           **1**
           **always**
               Always write it.

       **video_format _**integer_
           Specifies the video_format written into the sequence  display  extension  indicating  the
           source  of  the  video pictures. The default is **unspecified**, can be **component**, **pal**, **ntsc**,
           **secam **or **mac**.  For maximum compatibility, use **component**.

       **a53cc _**boolean_
           Import closed captions (which must be ATSC compatible format) into output.  Default is  1
           (on).

### png
       PNG image encoder.

       _Private_ _options_

       **dpi _**integer_
           Set physical density of pixels, in dots per inch, unset by default

       **dpm _**integer_
           Set physical density of pixels, in dots per meter, unset by default

### ProRes
       Apple ProRes encoder.

       FFmpeg contains 2 ProRes encoders, the prores-aw and prores-ks encoder.  The used encoder can
       be chosen with the "-vcodec" option.

       _Private_ _Options_ _for_ _prores-ks_

       **profile _**integer_
           Select the ProRes profile to encode

           **proxy**
           **lt**
           **standard**
           **hq**
           **4444**
           **4444xq**
       **quant_mat _**integer_
           Select quantization matrix.

           **auto**
           **default**
           **proxy**
           **lt**
           **standard**
           **hq**

           If  set  to _auto_, the matrix matching the profile will be picked.  If not set, the matrix
           providing the highest quality, _default_, will be picked.

       **bits_per_mb _**integer_
           How many bits to allot for coding one macroblock. Different profiles use between 200  and
           2400 bits per macroblock, the maximum is 8000.

       **mbs_per_slice _**integer_
           Number of macroblocks in each slice (1-8); the default value (8) should be good in almost
           all situations.

       **vendor _**string_
           Override  the  4-byte vendor ID.  A custom vendor ID like _apl0_ would claim the stream was
           produced by the Apple encoder.

       **alpha_bits _**integer_
           Specify number of bits for alpha component.  Possible values are _0_, _8_ and _16_.  Use  _0_  to
           disable alpha plane coding.

       _Speed_ _considerations_

       In the default mode of operation the encoder has to honor frame constraints (i.e. not produce
       frames  with  size  bigger  than  requested)  while  still  making  output picture as good as
       possible.  A frame containing a lot of small details is harder to compress  and  the  encoder
       would spend more time searching for appropriate quantizers for each slice.

       Setting a higher **bits_per_mb **limit will improve the speed.

       For  the  fastest encoding speed set the **qscale **parameter (4 is the recommended value) and do
       not set a size constraint.

### QSV Encoders
       The family of Intel QuickSync Video encoders (MPEG-2, H.264, HEVC, JPEG/MJPEG, VP9, AV1)

       _Ratecontrol_ _Method_

       The ratecontrol method is selected as follows:

       •   When **global_quality **is specified, a quality-based mode is used.  Specifically this  means
           either

           -   _CQP_  -  constant quantizer scale, when the **qscale **codec flag is also set (the **-qscale**
               ffmpeg option).

           -   _LA_ICQ_ - intelligent constant quality with lookahead, when the **look_ahead  **option  is
               also set.

           -   _ICQ_  --  intelligent  constant  quality  otherwise. For the ICQ modes, global quality
               range is 1 to 51, with 1 being the best quality.

       •   Otherwise, a bitrate-based mode is used. For all of those, you should  specify  at  least
           the desired average bitrate with the **b **option.

           -   _LA_ - VBR with lookahead, when the **look_ahead **option is specified.

           -   _VCM_ - video conferencing mode, when the **vcm **option is set.

           -   _CBR_ - constant bitrate, when **maxrate **is specified and equal to the average bitrate.

           -   _VBR_  -  variable  bitrate,  when **maxrate **is specified, but is higher than the average
               bitrate.

           -   _AVBR_ - average VBR mode, when  **maxrate  **is  not  specified,  both  **avbr_accuracy  **and
               **avbr_convergence  **are  set  to  non-zero. This mode is available for H264 and HEVC on
               Windows.

       Note that depending on your system, a different mode  than  the  one  you  specified  may  be
       selected  by  the  encoder.  Set  the  verbosity level to _verbose_ or higher to see the actual
       settings used by the QSV runtime.

       _Global_ _Options_ _->_ _MSDK_ _Options_

       Additional libavcodec global options are mapped to MSDK options as follows:

       •   **g/gop_size **-> **GopPicSize**

       •   **bf/max_b_frames**+1 -> **GopRefDist**

       •   **rc_init_occupancy/rc_initial_buffer_occupancy **-> **InitialDelayInKB**

       •   **slices **-> **NumSlice**

       •   **refs **-> **NumRefFrame**

       •   **b_strategy/b_frame_strategy **-> **BRefType**

       •   **cgop/CLOSED_GOP **codec flag -> **GopOptFlag**

       •   For the _CQP_ mode, the **i_qfactor/i_qoffset  **and  **b_qfactor/b_qoffset  **set  the  difference
           between _QPP_ and _QPI_, and _QPP_ and _QPB_ respectively.

       •   Setting  the  **coder **option to the value _vlc_ will make the H.264 encoder use CAVLC instead
           of CABAC.

       _Common_ _Options_

       Following options are used by all qsv encoders.

       _async_depth_
           Specifies how many asynchronous operations an application performs before the application
           explicitly synchronizes the result. If zero, the value is not specified.

       _preset_
           This option itemizes a range of choices from veryfast  (best  speed)  to  veryslow  (best
           quality).

           **veryfast**
           **faster**
           **fast**
           **medium**
           **slow**
           **slower**
           **veryslow**
       _forced_idr_
           Forcing I frames as IDR frames.

       _low_power_
           For encoders set this flag to ON to reduce power consumption and GPU usage.

       _Runtime_ _Options_

       Following options can be used durning qsv encoding.

       _global_quality_
       _i_quant_factor_
       _i_quant_offset_
       _b_quant_factor_
       _b_quant_offset_
           Supported  in  h264_qsv  and  hevc_qsv.   Change  these  value  to  reset  qsv codec's qp
           configuration.

       _max_frame_size_
           Supported in h264_qsv and hevc_qsv.  Change this value to reset qsv codec's  MaxFrameSize
           configuration.

       _gop_size_
           Change this value to reset qsv codec's gop configuration.

       _int_ref_type_
       _int_ref_cycle_size_
       _int_ref_qp_delta_
       _int_ref_cycle_dist_
           Supported  in  h264_qsv  and  hevc_qsv.   Change  these  value to reset qsv codec's Intra
           Refresh configuration.

       _qmax_
       _qmin_
       _max_qp_i_
       _min_qp_i_
       _max_qp_p_
       _min_qp_p_
       _max_qp_b_
       _min_qp_b_
           Supported in h264_qsv.  Change these value to reset qsv codec's max/min qp configuration.

       _low_delay_brc_
           Supported in h264_qsv, hevc_qsv and av1_qsv.  Change this  value  to  reset  qsv  codec's
           low_delay_brc configuration.

       _framerate_
           Change this value to reset qsv codec's framerate configuration.

       _bit_rate_
       _rc_buffer_size_
       _rc_initial_buffer_occupancy_
       _rc_max_rate_
           Change these value to reset qsv codec's bitrate control configuration.

       _pic_timing_sei_
           Supported   in   h264_qsv   and  hevc_qsv.   Change  this  value  to  reset  qsv  codec's
           pic_timing_sei configuration.

       _H264_ _options_

       These options are used by h264_qsv

       _extbrc_
           Extended bitrate control.

       _recovery_point_sei_
           Set this flag to insert the recovery point SEI message at the beginning  of  every  intra
           refresh cycle.

       _rdo_ Enable rate distortion optimization.

       _max_frame_size_
           Maximum encoded frame size in bytes.

       _max_frame_size_i_
           Maximum  encoded  frame  size  for I frames in bytes. If this value is set as larger than
           zero, then for I frames the value set by max_frame_size is ignored.

       _max_frame_size_p_
           Maximum encoded frame size for P frames in bytes. If this value is  set  as  larger  than
           zero, then for P frames the value set by max_frame_size is ignored.

       _max_slice_size_
           Maximum encoded slice size in bytes.

       _bitrate_limit_
           Toggle  bitrate  limitations.   Modifies  bitrate  to  be in the range imposed by the QSV
           encoder. Setting this flag off may lead  to  violation  of  HRD  conformance.  Mind  that
           specifying  bitrate below the QSV encoder range might significantly affect quality. If on
           this option takes effect in non CQP modes: if bitrate is not in the range imposed by  the
           QSV encoder, it will be changed to be in the range.

       _mbbrc_
           Setting  this  flag  enables  macroblock  level  bitrate  control that generally improves
           subjective visual quality. Enabling this flag may have negative impact on performance and
           objective visual quality metric.

       _low_delay_brc_
           Setting this flag turns on or off LowDelayBRC feautre in qsv plugin, which provides  more
           accurate  bitrate  control  to  minimize  the  variance of bitstream size frame by frame.
           Value: -1-default 0-off 1-on

       _adaptive_i_
           This flag controls insertion of I frames by the QSV encoder. Turn ON this flag  to  allow
           changing of frame type from P and B to I.

       _adaptive_b_
           This flag controls changing of frame type from B to P.

       _p_strategy_
           Enable P-pyramid: 0-default 1-simple 2-pyramid(bf need to be set to 0).

       _b_strategy_
           This option controls usage of B frames as reference.

       _dblk_idc_
           This option disable deblocking. It has value in range 0~2.

       _cavlc_
           If set, CAVLC is used; if unset, CABAC is used for encoding.

       _vcm_ Video conferencing mode, please see ratecontrol method.

       _idr_interval_
           Distance (in I-frames) between IDR frames.

       _pic_timing_sei_
           Insert picture timing SEI with pic_struct_syntax element.

       _single_sei_nal_unit_
           Put all the SEI messages into one NALU.

       _max_dec_frame_buffering_
           Maximum number of frames buffered in the DPB.

       _look_ahead_
           Use VBR algorithm with look ahead.

       _look_ahead_depth_
           Depth of look ahead in number frames.

       _look_ahead_downsampling_
           Downscaling factor for the frames saved for the lookahead analysis.

           **unknown**
           **auto**
           **off**
           **2x**
           **4x**
       _int_ref_type_
           Specifies  intra  refresh  type.  The major goal of intra refresh is improvement of error
           resilience without significant impact on encoded bitstream size caused by I  frames.  The
           SDK  encoder  achieves  this  by encoding part of each frame in refresh cycle using intra
           MBs. _none_ means no refresh. _vertical_ means vertical refresh, by column of MBs. _horizontal_
           means horizontal refresh, by rows of  MBs.  _slice_  means  horizontal  refresh  by  slices
           without  overlapping.  In  case  of  _slice_, in_ref_cycle_size is ignored. To enable intra
           refresh, B frame should be set to 0.

       _int_ref_cycle_size_
           Specifies number of pictures within refresh cycle starting from 2. 0 and  1  are  invalid
           values.

       _int_ref_qp_delta_
           Specifies  QP  difference for inserted intra MBs. This is signed value in [-51, 51] range
           if target encoding bit-depth for luma samples is 8 and this range is  [-63,  63]  for  10
           bit-depth or [-75, 75] for 12 bit-depth respectively.

       _int_ref_cycle_dist_
           Distance between the beginnings of the intra-refresh cycles in frames.

       _profile_
           **unknown**
           **baseline**
           **main**
           **high**
       _a53cc_
           Use A53 Closed Captions (if available).

       _aud_ Insert the Access Unit Delimiter NAL.

       _mfmode_
           Multi-Frame Mode.

           **off**
           **auto**
       _repeat_pps_
           Repeat pps for every frame.

       _max_qp_i_
           Maximum video quantizer scale for I frame.

       _min_qp_i_
           Minimum video quantizer scale for I frame.

       _max_qp_p_
           Maximum video quantizer scale for P frame.

       _min_qp_p_
           Minimum video quantizer scale for P frame.

       _max_qp_b_
           Maximum video quantizer scale for B frame.

       _min_qp_b_
           Minimum video quantizer scale for B frame.

       _scenario_
           Provides a hint to encoder about the scenario for the encoding session.

           **unknown**
           **displayremoting**
           **videoconference**
           **archive**
           **livestreaming**
           **cameracapture**
           **videosurveillance**
           **gamestreaming**
           **remotegaming**
       _avbr_accuracy_
           Accuracy of the AVBR ratecontrol (unit of tenth of percent).

       _avbr_convergence_
           Convergence of the AVBR ratecontrol (unit of 100 frames)

           The  parameters  _avbr_accuracy_  and _avbr_convergence_ are for the average variable bitrate
           control (AVBR) algorithm.  The  algorithm  focuses  on  overall  encoding  quality  while
           meeting  the  specified bitrate, _target_bitrate_, within the accuracy range _avbr_accuracy_,
           after a _avbr_Convergence_ period. This method does not follow HRD and the instant  bitrate
           is not capped or padded.

       _skip_frame_
           Use  per-frame metadata "qsv_skip_frame" to skip frame when encoding. This option defines
           the usage of this metadata.

           **no_skip**
               Frame skipping is disabled.

           **insert_dummy**
               Encoder inserts into bitstream frame where all macroblocks are encoded as skipped.

           **insert_nothing**
               Similar to insert_dummy, but encoder inserts  nothing  into  bitstream.  The  skipped
               frames  are still used in brc. For example, gop still include skipped frames, and the
               frames after skipped frames will be larger in size.

           **brc_only**
               skip_frame metadata indicates the number of missed frames before the current frame.

       _HEVC_ _Options_

       These options are used by hevc_qsv

       _extbrc_
           Extended bitrate control.

       _recovery_point_sei_
           Set this flag to insert the recovery point SEI message at the beginning  of  every  intra
           refresh cycle.

       _rdo_ Enable rate distortion optimization.

       _max_frame_size_
           Maximum encoded frame size in bytes.

       _max_frame_size_i_
           Maximum  encoded  frame  size  for I frames in bytes. If this value is set as larger than
           zero, then for I frames the value set by max_frame_size is ignored.

       _max_frame_size_p_
           Maximum encoded frame size for P frames in bytes. If this value is  set  as  larger  than
           zero, then for P frames the value set by max_frame_size is ignored.

       _max_slice_size_
           Maximum encoded slice size in bytes.

       _mbbrc_
           Setting  this  flag  enables  macroblock  level  bitrate  control that generally improves
           subjective visual quality. Enabling this flag may have negative impact on performance and
           objective visual quality metric.

       _low_delay_brc_
           Setting this flag turns on or off LowDelayBRC feautre in qsv plugin, which provides  more
           accurate  bitrate  control  to  minimize  the  variance of bitstream size frame by frame.
           Value: -1-default 0-off 1-on

       _adaptive_i_
           This flag controls insertion of I frames by the QSV encoder. Turn ON this flag  to  allow
           changing of frame type from P and B to I.

       _adaptive_b_
           This flag controls changing of frame type from B to P.

       _p_strategy_
           Enable P-pyramid: 0-default 1-simple 2-pyramid(bf need to be set to 0).

       _b_strategy_
           This option controls usage of B frames as reference.

       _dblk_idc_
           This option disable deblocking. It has value in range 0~2.

       _idr_interval_
           Distance (in I-frames) between IDR frames.

           **begin_only**
               Output an IDR-frame only at the beginning of the stream.

       _load_plugin_
           A user plugin to load in an internal session.

           **none**
           **hevc_sw**
           **hevc_hw**
       _load_plugins_
           A :-separate list of hexadecimal plugin UIDs to load in an internal session.

       _look_ahead_depth_
           Depth of look ahead in number frames, available when extbrc option is enabled.

       _profile_
           Set the encoding profile (scc requires libmfx >= 1.32).

           **unknown**
           **main**
           **main10**
           **mainsp**
           **rext**
           **scc**
       _tier_
           Set  the  encoding  tier (only level >= 4 can support high tier).  This option only takes
           effect when the level option is specified.

           **main**
           **high**
       _gpb_ 1: GPB (generalized P/B frame)

           0: regular P frame.

       _tile_cols_
           Number of columns for tiled encoding.

       _tile_rows_
           Number of rows for tiled encoding.

       _aud_ Insert the Access Unit Delimiter NAL.

       _pic_timing_sei_
           Insert picture timing SEI with pic_struct_syntax element.

       _transform_skip_
           Turn this option ON to enable transformskip. It is supported on platform equal  or  newer
           than ICL.

       _int_ref_type_
           Specifies  intra  refresh  type.  The major goal of intra refresh is improvement of error
           resilience without significant impact on encoded bitstream size caused by I  frames.  The
           SDK  encoder  achieves  this  by encoding part of each frame in refresh cycle using intra
           MBs. _none_ means no refresh. _vertical_ means vertical refresh, by column of MBs. _horizontal_
           means horizontal refresh, by rows of  MBs.  _slice_  means  horizontal  refresh  by  slices
           without  overlapping.  In  case  of  _slice_, in_ref_cycle_size is ignored. To enable intra
           refresh, B frame should be set to 0.

       _int_ref_cycle_size_
           Specifies number of pictures within refresh cycle starting from 2. 0 and  1  are  invalid
           values.

       _int_ref_qp_delta_
           Specifies  QP  difference for inserted intra MBs. This is signed value in [-51, 51] range
           if target encoding bit-depth for luma samples is 8 and this range is  [-63,  63]  for  10
           bit-depth or [-75, 75] for 12 bit-depth respectively.

       _int_ref_cycle_dist_
           Distance between the beginnings of the intra-refresh cycles in frames.

       _max_qp_i_
           Maximum video quantizer scale for I frame.

       _min_qp_i_
           Minimum video quantizer scale for I frame.

       _max_qp_p_
           Maximum video quantizer scale for P frame.

       _min_qp_p_
           Minimum video quantizer scale for P frame.

       _max_qp_b_
           Maximum video quantizer scale for B frame.

       _min_qp_b_
           Minimum video quantizer scale for B frame.

       _scenario_
           Provides a hint to encoder about the scenario for the encoding session.

           **unknown**
           **displayremoting**
           **videoconference**
           **archive**
           **livestreaming**
           **cameracapture**
           **videosurveillance**
           **gamestreaming**
           **remotegaming**
       _avbr_accuracy_
           Accuracy of the AVBR ratecontrol (unit of tenth of percent).

       _avbr_convergence_
           Convergence of the AVBR ratecontrol (unit of 100 frames)

           The  parameters  _avbr_accuracy_  and _avbr_convergence_ are for the average variable bitrate
           control (AVBR) algorithm.  The  algorithm  focuses  on  overall  encoding  quality  while
           meeting  the  specified bitrate, _target_bitrate_, within the accuracy range _avbr_accuracy_,
           after a _avbr_Convergence_ period. This method does not follow HRD and the instant  bitrate
           is not capped or padded.

       _skip_frame_
           Use  per-frame metadata "qsv_skip_frame" to skip frame when encoding. This option defines
           the usage of this metadata.

           **no_skip**
               Frame skipping is disabled.

           **insert_dummy**
               Encoder inserts into bitstream frame where all macroblocks are encoded as skipped.

           **insert_nothing**
               Similar to insert_dummy, but encoder inserts  nothing  into  bitstream.  The  skipped
               frames  are still used in brc. For example, gop still include skipped frames, and the
               frames after skipped frames will be larger in size.

           **brc_only**
               skip_frame metadata indicates the number of missed frames before the current frame.

       _MPEG2_ _Options_

       These options are used by mpeg2_qsv

       _profile_
           **unknown**
           **simple**
           **main**
           **high**

       _VP9_ _Options_

       These options are used by vp9_qsv

       _profile_
           **unknown**
           **profile0**
           **profile1**
           **profile2**
           **profile3**
       _tile_cols_
           Number of columns for tiled encoding (requires libmfx >= 1.29).

       _tile_rows_
           Number of rows for tiled encoding (requires libmfx  >= 1.29).

       _AV1_ _Options_

       These options are used by av1_qsv (requires libvpl).

       _profile_
           **unknown**
           **main**
       _tile_cols_
           Number of columns for tiled encoding.

       _tile_rows_
           Number of rows for tiled encoding.

       _adaptive_i_
           This flag controls insertion of I frames by the QSV encoder. Turn ON this flag  to  allow
           changing of frame type from P and B to I.

       _adaptive_b_
           This flag controls changing of frame type from B to P.

       _b_strategy_
           This option controls usage of B frames as reference.

       _extbrc_
           Extended bitrate control.

       _look_ahead_depth_
           Depth of look ahead in number frames, available when extbrc option is enabled.

       _low_delay_brc_
           Setting  this flag turns on or off LowDelayBRC feautre in qsv plugin, which provides more
           accurate bitrate control to minimize the variance  of  bitstream  size  frame  by  frame.
           Value: -1-default 0-off 1-on

### max_frame_size
           Set  the  allowed  max  size  in  bytes  for  each  frame.  If the frame size exceeds the
           limitation, encoder will adjust the QP value to control the frame size.  Invalid  in  CQP
           rate control mode.

### snow
       _Options_

### iterative_dia_size
           dia size for the iterative motion estimation

### VAAPI encoders
       Wrappers for hardware encoders accessible via VAAPI.

       These  encoders  only accept input in VAAPI hardware surfaces.  If you have input in software
       frames, use the **hwupload **filter to upload them to the GPU.

       The following standard libavcodec options are used:

       •   **g **/ **gop_size**

       •   **bf **/ **max_b_frames**

       •   **profile**

           If not set, this will be determined automatically from the format of the input frames and
           the profiles supported by the driver.

       •   **level**

       •   **b **/ **bit_rate**

       •   **maxrate **/ **rc_max_rate**

       •   **bufsize **/ **rc_buffer_size**

       •   **rc_init_occupancy **/ **rc_initial_buffer_occupancy**

       •   **compression_level**

           Speed / quality tradeoff: higher values are faster / worse quality.

       •   **q **/ **global_quality**

           Size / quality tradeoff: higher values are smaller / worse quality.

       •   **qmin**

       •   **qmax**

       •   **i_qfactor **/ **i_quant_factor**

       •   **i_qoffset **/ **i_quant_offset**

       •   **b_qfactor **/ **b_quant_factor**

       •   **b_qoffset **/ **b_quant_offset**

       •   **slices**

       All encoders support the following options:

### low_power
           Some drivers/platforms offer a second encoder for some codecs intended to use less  power
           than  the  default  encoder;  setting this option will attempt to use that encoder.  Note
           that it may support a reduced feature set, so some other options may not be available  in
           this mode.

### idr_interval
           Set the number of normal intra frames between full-refresh (IDR) frames in open-GOP mode.
           The  intra  frames are still IRAPs, but will not include global headers and may have non-
           decodable leading pictures.

### b_depth
           Set the B-frame reference depth.  When set to one (the default), all B-frames will  refer
           only  to  P- or I-frames.  When set to greater values multiple layers of B-frames will be
           present, frames in each layer only referring to frames in higher layers.

### async_depth
           Maximum processing parallelism. Increase this to improve single channel performance. This
           option doesn't work if driver doesn't implement vaSyncBuffer function. Please  make  sure
           there are enough hw_frames allocated if a large number of async_depth is used.

### max_frame_size
           Set  the  allowed  max  size  in  bytes  for  each  frame.  If the frame size exceeds the
           limitation, encoder will adjust the QP value to control the frame size.  Invalid  in  CQP
           rate control mode.

### rc_mode
           Set the rate control mode to use.  A given driver may only support a subset of modes.

           Possible modes:

           **auto**
               Choose the mode automatically based on driver support and the other options.  This is
               the default.

           **CQP **Constant-quality.

           **CBR **Constant-bitrate.

           **VBR **Variable-bitrate.

           **ICQ **Intelligent constant-quality.

           **QVBR**
               Quality-defined variable-bitrate.

           **AVBR**
               Average variable bitrate.

       Each encoder also has its own specific options:

### av1_vaapi
           **profile  **sets the value of _seq_profile_.  **tier **sets the value of _seq_tier_.  **level **sets the
           value of _seq_level_idx_.

           **tiles**
               Set the number of tiles to encode the input video with, as columns x rows.   (default
               is auto, which means use minimal tile column/row number).

           **tile_groups**
               Set  tile  groups  number. All the tiles will be distributed as evenly as possible to
               each tile group. (default is 1).

### h264_vaapi
           **profile **sets the value of _profile_idc_ and  the  _constraint_set*_flag_s.   **level  **sets  the
           value of _level_idc_.

           **coder**
               Set entropy encoder (default is _cabac_).  Possible values:

               **ac**
               **cabac**
                   Use CABAC.

               **vlc**
               **cavlc**
                   Use CAVLC.

           **aud **Include access unit delimiters in the stream (not included by default).

           **sei **Set SEI message types to include.  Some combination of the following values:

               **identifier**
                   Include   a  _user_data_unregistered_  message  containing  information  about  the
                   encoder.

               **timing**
                   Include picture timing parameters (_buffering_period_ and _pic_timing_ messages).

               **recovery_point**
                   Include recovery points where appropriate (_recovery_point_ messages).

### hevc_vaapi
           **profile  **and  **level  **set  the  values  of   _general_profile_idc_   and   _general_level_idc_
           respectively.

           **aud **Include access unit delimiters in the stream (not included by default).

           **tier**
               Set  _general_tier_flag_.  This may affect the level chosen for the stream if it is not
               explicitly specified.

           **sei **Set SEI message types to include.  Some combination of the following values:

               **hdr **Include HDR metadata if the input frames have it (_mastering_display_colour_volume_
                   and _content_light_level_ messages).

           **tiles**
               Set the number of tiles to encode the input video with, as columns  x  rows.   Larger
               numbers  allow  greater  parallelism  in both encoding and decoding, but may decrease
               coding efficiency.

### mjpeg_vaapi
           Only  baseline  DCT  encoding  is  supported.   The  encoder  always  uses  the  standard
           quantisation  and  huffman tables - **global_quality **scales the standard quantisation table
           (range 1-100).

           For YUV, 4:2:0, 4:2:2 and 4:4:4 subsampling modes are supported.  RGB is also  supported,
           and will create an RGB JPEG.

           **jfif**
               Include JFIF header in each frame (not included by default).

           **huffman**
               Include  standard  huffman  tables (on by default).  Turning this off will save a few
               hundred bytes in each output  frame,  but  may  lose  compatibility  with  some  JPEG
               decoders which don't fully handle MJPEG.

### mpeg2_vaapi
           **profile **and **level **set the value of _profile_and_level_indication_.

### vp8_vaapi
           B-frames are not supported.

           **global_quality **sets the _q_idx_ used for non-key frames (range 0-127).

           **loop_filter_level**
           **loop_filter_sharpness**
               Manually set the loop filter parameters.

### vp9_vaapi
           **global_quality **sets the _q_idx_ used for P-frames (range 0-255).

           **loop_filter_level**
           **loop_filter_sharpness**
               Manually set the loop filter parameters.

           B-frames  are  supported,  but  the  output  stream is always in encode order rather than
           display order.  If B-frames are enabled, it may be necessary to use  the  **vp9_raw_reorder**
           bitstream filter to modify the output stream to display frames in the correct order.

           Only  normal frames are produced - the **vp9_superframe **bitstream filter may be required to
           produce a stream usable with all decoders.

### vbn
       Vizrt Binary Image encoder.

       This format is used by the broadcast vendor Vizrt  for  quick  texture  streaming.   Advanced
       features  of  the format such as LZW compression of texture data or generation of mipmaps are
       not supported.

       _Options_

       **format _**string_
           Sets the texture compression used by the VBN file. Can be _dxt1_, _dxt5_ or _raw_.  Default  is
           _dxt5_.

### vc2
       SMPTE  VC-2  (previously  BBC  Dirac  Pro).  This  codec  was primarily aimed at professional
       broadcasting but since it supports yuv420, yuv422 and yuv444 at  8  (limited  range  or  full
       range),  10 or 12 bits, this makes it suitable for other tasks which require low overhead and
       low compression (like screen recording).

       _Options_

       **b   **Sets target video bitrate. Usually that's around 1:6 of the  uncompressed  video  bitrate
           (e.g.  for  1920x1080 50fps yuv422p10 that's around 400Mbps). Higher values (close to the
           uncompressed bitrate) turn on lossless compression mode.

### field_order
           Enables field coding when set (e.g. to tt -  top  field  first)  for  interlaced  inputs.
           Should  increase  compression with interlaced content as it splits the fields and encodes
           each separately.

### wavelet_depth
           Sets the total amount of wavelet transforms to apply, between 1 and 5  (default).   Lower
           values  reduce  compression  and quality. Less capable decoders may not be able to handle
           values of **wavelet_depth **over 3.

### wavelet_type
           Sets the transform type. Currently only _5_3_  (LeGall)  and  _9_7_  (Deslauriers-Dubuc)  are
           implemented, with 9_7 being the one with better compression and thus is the default.

### slice_width
### slice_height
           Sets  the  slice  size  for  each slice. Larger values result in better compression.  For
           compatibility with other more limited decoders use **slice_width **of 32 and **slice_height  **of
           8.

### tolerance
           Sets  the  undershoot tolerance of the rate control system in percent. This is to prevent
           an expensive search from being run.

       **qm  **Sets the quantization matrix preset to use by default or when **wavelet_depth **is set to 5

           -   _default_ Uses the default quantization matrix from the specifications,  extended  with
               values  for  the fifth level. This provides a good balance between keeping detail and
               omitting artifacts.

           -   _flat_ Use a completely zeroed out quantization matrix. This increases PSNR  but  might
               reduce perception. Use in bogus benchmarks.

           -   _color_ Reduces detail but attempts to preserve color at extremely low bitrates.

## SUBTITLES ENCODERS
### dvdsub
       This  codec  encodes  the  bitmap  subtitle  format that is used in DVDs.  Typically they are
       stored in VOBSUB file pairs (*.idx + *.sub), and they can also be used in Matroska files.

       _Options_

### palette
           Specify the global palette used by the bitmaps.

           The format for this option is a string containing 16 24-bits hexadecimal numbers (without
           0x prefix) separated by commas, for example  "0d00ee,  ee450d,  101010,  eaeaea,  0ce60b,
           ec14ed, ebff0b, 0d617a, 7b7b7b, d1d1d1, 7b2a0e, 0d950c, 0f007b, cf0dec, cfa80c, 7c127b".

### even_rows_fix
           When  set  to  1,  enable  a  work-around that makes the number of pixel rows even in all
           subtitles.  This fixes a problem with some players that cut off the  bottom  row  if  the
           number  is  odd.   The  work-around  just  adds  a  fully transparent row if needed.  The
           overhead is low, typically one byte per subtitle on average.

           By default, this work-around is disabled.

## SEE ALSO
       [**ffmpeg**(1)](https://www.chedong.com/phpMan.php/man/ffmpeg/1/markdown), [**ffplay**(1)](https://www.chedong.com/phpMan.php/man/ffplay/1/markdown), [**ffprobe**(1)](https://www.chedong.com/phpMan.php/man/ffprobe/1/markdown), [**libavcodec**(3)](https://www.chedong.com/phpMan.php/man/libavcodec/3/markdown)

## AUTHORS
       The FFmpeg developers.

       For   details   about   the   authorship,   see   the   Git   history    of    the    project
       (<https://git.ffmpeg.org/ffmpeg>),  e.g.  by  typing  the  command **git log **in the FFmpeg source
       directory, or browsing the online repository at <**<https://git.ffmpeg.org/ffmpeg>**>.

       Maintainers for the specific components are listed in the file _MAINTAINERS_ in the source code
       tree.

                                                                                    [_FFMPEG-CODECS_(1)](https://www.chedong.com/phpMan.php/man/FFMPEG-CODECS/1/markdown)