NAME

       ojph_compress  -  This program reads in an image of a certain type and converts it to a HTJ2K (JPH) file.
       It is part of the OpenJPH library.

DESCRIPTION

   The following arguments are necessary:

       -i input file name (either pgm, ppm, pfm, tif(f), or raw(yuv))

       -o output file name

   The following option has a default value (optional):
       -num_decomps
              (5) number of decompositions

       -qstep (0.00001...0.5) quantization step size for lossy compression;  quantization  steps  size  for  all
              subbands are derived from this value. {The default value for 8bit images is 0.0039}

       -reversible
              <true | false> If this is 'false', an irreversible or lossy compression is employed, using the 9/7
              wavelet  transform;  if  'true',  a  reversible compression is performed, where the 5/3 wavelet is
              used.  Default value is 'false'.

       -colour_trans <true | false> This option employs a color transform,

              to transform RGB color images into the YUV domain.  This  option  should  NOT  be  used  with  YUV
              images,  because they have already been transformed.  If there are three color components that are
              downsampled by the same amount then this option can be 'true' or  'false'.  This  option  is  also
              available when there are more than three colour components, where it is applied to the first three
              colour components.

       -prog_order
              (RPCL) is the progression order, and can be one of: LRCP, RLCP, RPCL, PCRL, CPRL.

       -block_size
              {x,y}  (64,64)  where x and y are the height and width of a codeblock. In unix-like environment, {
              and } must be preceded by a \.

       -precincts
              {x,y},{x,y},...,{x,y} where {x,y} is the precinct size starting from the coarsest resolution;  the
              last precinct is repeated for all finer resolutions

       -tile_offset
              {x,y} tile offset.

       -tile_size
              {x,y} tile width and height.

       -image_offset {x,y} image offset from origin.

       -tileparts
              (None)  employ tilepart divisions at each resolution, indicated by the letter R, and/or component,
              indicated by the letter C. For both, use "-tileparts RC".

       -tlm_marker
              <true | false> if 'true', a TLM marker is inserted.  Default value is false.

       -profile
              (None) is the profile, the code will check if the selected options meet  the  profile.   Currently
              only BROADCAST and IMF are supported.  This automatically sets tlm_marker to true and tileparts to
              C.

       -com   (None)  if  set,  inserts a COM marker with the specified string. If the string has spaces, please
              use double quotes, as in -com "This is a comment".

       When the input file is a YUV file, these arguments need to be

              supplied: -dims      {x,y} x is image width, y is height -num_comps number of  components  -signed
              a comma-separated list of true or false parameters, one

              for each component; for example: true,false,false

       -bit_depth a comma-separated list of bit depth values, one per

              component; for example: 12,10,10

       -downsamp
              {x,y},{x,y},...,{x,y} a list of x,y points, one for each component; for example {1,1},{2,2},{2,2}

       .pfm  files  receive  special  treatment. Currently, lossy compression with these files is not supported,
       only lossless. When these files are used, the NLT segment  marker  is  automatically  inserted  into  the
       codestream when needed, as explained shortly. The following arguments can be useful for this file type.

       -signed
              a  comma-separated  list  of  true  or  false  parameters,  one  for  each component; for example:
              true,false,false.  If you are sure that all sample values are positive or 0, set the corresponding
              entry to false; otherwise set it to true.  When a component entry is set to true, an  NLT  segment
              marker  segment is inserted into the codestream.  The NLT segment specifies a non-linear transform
              that changes only negative values, producing better coding efficiency.   The  NLT  segment  marker
              might be less supported in other encoders.

       -bit_depth a comma-separated list of bit depth values, one per

              component;  for  example:  12,10,10.  Floating value numbers are treated as integers, and they are
              shifted to the right, keeping only the specified number of bits. Up  to  32  bits  (which  is  the
              default) are supported.

AUTHOR

       This manual page was written by Mathieu Malaterre <malat@debian.org> for the Debian GNU/Linux system (but
       may be used by others).

ojph_compress 0.25.3                              December 2025                                 OJPH_COMPRESS(1)