Ubuntu Manpage: jbgtopbm - JBIG1 to portable bitmap file converter

Provided by: jbigkit-bin_2.1-3.1ubuntu0.20.04.1_amd64

NAME

       jbgtopbm - JBIG1 to portable bitmap file converter

SYNOPSIS

       jbgtopbm [ options ] [ input-file | -  [ output-file ]]

DESCRIPTION

       Reads  in a JBIG1 bi-level image entity (BIE) from a file or standard input, decompresses it, and outputs
       a portable bitmap (PBM) file.

       JBIG1 is a highly effective lossless compression algorithm for bi-level images (one bit per pixel), which
       is particularly suitable for scanned document pages.

       A  JBIG1 encoded image can be stored in several resolutions in one or several BIEs. All resolution layers
       except the lowest one are stored efficiently as differences to the next lower resolution  layer.  Options
       -x  and -y can be used to stop the decompression at a specified maximal output image size. With option -m
       the input file can consist of multiple concatenated BIEs which contain  different  increasing  resolution
       layers of the same image.

       If more than one bit per pixel is stored in the JBIG1 file, then a PGM file will be produced.

OPTIONS

- A single hyphen instead of an input file name will cause jbgtopbm to read the data from
standard input instead from a file.

-x number Decode only up to the largest resolution layer which is still not more than number pixels
wide. If no such resolution layer exists, then use the smallest one available.

-y number Decode only up to the largest resolution layer which is still not more than number pixels
high. If no such resolution layer exists, then use the smallest one available. Options -x
and -y can also be used together in which case the largest layer that satisfies both limits
will be selected.

-m Process multiple concatenated BIEs. If there are bytes left after the final SDE in the
first BIE, then with this option jbgtopbm will attempt to decode these as the start of
another BIE that may contain higher resolution data. Normally, any remaining bytes will
generate a warning message.

-b Use binary values instead of Gray code words in order to decode pixel values from multiple
bitplanes. This option has only an effect if the input has more than one bitplane and a PGM
output file is produced. Note that the decoder has to be used in the same mode as the
encoder and cannot determine from the BIE, whether Gray or binary code words were used by
the encoder.

-d Diagnose a single BIE. With this option, jbgtopbm will print a summary of the header
information found in the input file, followed by a list of all PSCD and ESC marker
sequences encountered until the end of the file is reached.

-p number If the input contains multiple bitplanes, then extract only the specified single plane as a
PBM file. The first plane has number 0.

BUGS

       Using standard input and standard output for binary  data  works  only  on  systems  where  there  is  no
       difference  between binary and text streams (e.g., Unix). On other systems (e.g., MS-DOS), using standard
       input or standard output may cause control characters like CR or LF to be inserted or  deleted  and  this
       will damage the binary data.

STANDARDS

       This  program  implements  the  JBIG1 image coding algorithm as specified in ISO/IEC 11544:1993 and ITU-T
       T.82(1993).

AUTHOR

       The jbgtopbm program is part of the JBIG-KIT package, which has been developed by Markus Kuhn.  The  most
       recent    version    of    this    portable   JBIG1   library   and   tools   set   is   available   from
       <http://www.cl.cam.ac.uk/~mgk25/jbigkit/>.