# man > jpeg2ktopam(1)
*Source: tldr-pages*
---
_Jpeg2ktopam_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown) General Commands Manual _Jpeg2ktopam_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown)
## NAME
jpeg2ktopam - convert JPEG-2000 code stream to PAM/PNM
## SYNOPSIS
**jpeg2ktopam **[**-verbose**] [**-debuglevel=_**number_] _filename_
## OPTION USAGE
Minimum unique abbreviation of option is acceptable. You may use double hyphens instead of
single hyphen to denote options. You may use white space in place of the equals sign to sep‐
arate an option name from its value.
## DESCRIPTION
This program is part of [**Netpbm**(1)](https://www.chedong.com/phpMan.php/man/Netpbm/1/markdown).
**jpeg2ktopam **converts the named JPEG-2000 file (JP2 or JPC), or Standard Input if no file is
named, to a PBM, PGM, PPM, or PAM file on Standard Output.
The JPEG-2000 specification specifies two different formats: JP2 and JPEG-2000 code stream
(JPC). JP2 represents a visual image quite specifically, whereas JPC is a more or less arbi‐
trary array of codes. A JP2 image contains a JPC stream and metadata describing how that
stream represents a visual image. **jpeg2ktopam **converts both.
If the color space identified in the image is grayscale (JAS_IMAGE_CS_GRAY), **jpeg2ktopam **gen‐
erates a PGM image, unless the image contains only one bit per pixel, in which case
**jpeg2ktopam **generates PBM. If the color space is RGB (JAS_IMAGE_CS_RGB), **jpeg2ktopam **gener‐
ates a PPM image. If the input image is anything else, **jpeg2ktopam **generates a PAM image
with no tuple type identified.
In the PGM and PPM cases, **jpeg2ktopam **assumes the intensity values in the input image have
the same meaning as for PGM and PPM. One thing that implies is the ITU-R Recommendation
BT.709 color space, which means the assumption is false for JP2 input. JP2 input uses SRGB
color encoding. So if you use **jpeg2ktopam **to convert a JP2 image to PPM, it changes the vi‐
sual image (slightly) -- the colors in the output are not the same as in the input.
In the PAM image, the output samples are numerically identical to the input samples. If the
input samples are signed, they are represented in two's complement form in the output (be‐
cause PAM samples are always unsigned). The PAM plane numbers are identical to the JPC com‐
ponent numbers.
A JPEG-2000 image has a "precision," which is the number of bits used for each code (in
Netpbm lingo, "sample"). Actually, each component has a separate precision. The maxval of a
PGM, PPM, or PAM output is the largest number you can represent in the JPEG-2000 precision of
the JPEG-2000 component with the greatest precision. The samples in all components are
scaled to that maxval. So if the red component has a precision of 4 bits and the green com‐
ponent has a precision of 6 bits, the maxval is 63 and the red component codes from the
JPEG-2000 image are multiplied by 63/15 to generate the output samples.
**jpeg2ktopam **interprets the JPEG-2000 input with the ]8;;\Jasper JPEG-2000 library]8;;\ . See documen‐
tation of the library for details on what **jpeg2ktopam **handles. Note that the Jasper library
contains facilities for writing PNM images, but **jpeg2ktopam **does not use those. It uses the
Netpbm library instead. Note that the makers of the Jasper library write it "JasPer," but
Netpbm documentation follows standard American English typography rules, which don't allow
that kind of capitalization.
Use **pamtojpeg2k **to convert in the other direction.
The program **jasper**, which is packaged with the Jasper JPEG-2000 library, also converts be‐
tween JPEG-2000 and PNM formats. Because it's packaged with the library, it may exploit it
better, especially recently added features. However, since it does not use the Netpbm li‐
brary to read and write the Netpbm formats, it doesn't do as good a job on that side.
## OPTIONS
In addition to the options common to all programs based on libnetpbm (most notably **-quiet**,
see ]8;;index.html#commonoptions\ Common Options]8;;\ ), **jpeg2ktopam **recognizes the following command line options:
### -verbose
This option causes **jpeg2ktopam **to issue informational messages about the conversion
process.
### -debuglevel
This option controls debug messages from the Jasper library. **jpeg2ktopam **passes _num‐_
_ber_ as the debug level to the Jasper JPEG-2000 decoder.
## EXAMPLES
jpeg2ktopam myimg.jpc >myimg.ppm
## ABOUT JPEG-2000
See **the pamtojpeg2k [manual**(1)](https://www.chedong.com/phpMan.php/man/manual/1/markdown) for general information on JPEG-2000 compression and the
JPEG-2000 formats.
## SEE ALSO
[**pamtojpeg2k**(1)](https://www.chedong.com/phpMan.php/man/pamtojpeg2k/1/markdown), [**jpegtopnm**(1)](https://www.chedong.com/phpMan.php/man/jpegtopnm/1/markdown), [**ppm**(1)](https://www.chedong.com/phpMan.php/man/ppm/1/markdown), [**pgm**(1)](https://www.chedong.com/phpMan.php/man/pgm/1/markdown), [**pbm**(1)](https://www.chedong.com/phpMan.php/man/pbm/1/markdown), [**pam**(1)](https://www.chedong.com/phpMan.php/man/pam/1/markdown),
## HISTORY
**jpeg2ktopam **was added to Netpbm in Release 10.12 (November 2002).
Before Netpbm 10.49 (December 2009), **jpeg2ktopam **could not convert a JP2 file -- only JPC.
## DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master
documentation is at
****
netpbm documentation 08 October 2009 _Jpeg2ktopam_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown)