NAME

       grk_decompress - decompresses an image in the JPEG 2000 format to a different image format

SYNOPSIS

       grk_dcompress [-i infile.j2k] [-o outfile.bmp]

DESCRIPTION

   Options
       -h,  -help

       Print a help message and exit.

       -version

       Print library version and exit.

   -v, -verbose
       Output  information  and  warnings  about  decoding to console (errors are always output).
       Default is false i.e. console is silent by default.

   -i, -InputFile [file]
       Input file.  Either this argument or the -ImgDir argument  described  below  is  required.
       Valid  input  image  extensions  are J2K, JP2 and JPC.  When using this option output file
       must be specified using -o.

   -o, -OutputFile [file]
       Output file.  Required when using -i option.  See above for supported file  types.   If  a
       PGX  filename  is  given,  there  will be as many output files as there are components: an
       index starting from 0 will then be appended to the output filename, just  before  the  pgx
       extension.   If  a  PGM  filename is given and there are more than one component, only the
       first component will be written to the file.

   -y, -ImgDir [directory path]
       Path to the folder where the compressed images are stored.  Either this argument or the -i
       argument  described  above is required.  When image files are in the same directory as the
       executable, this can be indicated by a dot . argument.  When using this option, the output
       format must be specified using -OutFor.  The output images are saved in the same folder.

   `-a, -OutDir [output directory]’
       Output  directory  where compressed files are stored.  Only relevant when the -ImgDir flag
       is set.  Default: same directory as specified by -ImgDir.

   -O, -OutFor [format]
       Output format used to decompress the code streams.  Required when -ImgDir option is  used.
       See above for supported formats.

   -r, -Reduce [reduce factor]
       Reduce  factor.   Set  the number of highest resolution levels to be discarded.  The image
       resolution is effectively divided by 2 to the power of the  number  of  discarded  levels.
       The  reduce  factor  is limited by the smallest total number of decomposition levels among
       tiles.

   -l, -Layer [layer number]
       Layer number.  Set the maximum number of quality layers to decode.   If  there  are  fewer
       quality layers than the specified number, all quality layers will be decoded.

   -d, -DecodeRegion [x0,y0,x1,y1]
       Decode  a sub-region of the image.  If (X,Y) is a location in the image, then it will only
       be decoded if x0 <= X < x1 and y0 <= Y < y1.  By default, the entire image is decoded.

   -c, -Compression [compression value]
       Compress output image data.  Currently, this flag is only applicable when output format is
       set to TIF.  Possible values are {NONE, LZW,JPEG, PACKBITS.  ZIP,LZMA,ZSTD,WEBP}.  Default
       value is NONE.

   -L, -CompressionLevel [compression level]
       “Quality”  of  compression.   Currently  only  implemented  for  PNG  format.   For   PNG,
       compression level ranges from 0 (no compression) up to 9.  Grok default value is 3.

       Note:  PNG  is  always  lossless,  so  using  a  different level will not affect the image
       quality.  It only changes the speed vs file size tradeoff.

   -t, -TileIndex [tile index]
       Only decode tile with specified index.  Index follows the JPEG2000  convention  from  top-
       left to bottom-right.  By default all tiles are decoded.

   -p, -Precision [component 0 precision[C|S],component 1 precision[C|S],...]
       Force  precision (bit depth) of components.  There must be at least one value present, but
       there is no limit on the number of values.  The  last  values  are  ignored  if  too  many
       values.   If  there  are  fewer  values  than  components,  the last value is used for the
       remaining components.  If  C  is  specified  (default),  values  are  clipped.   If  S  is
       specified,  values  are  scaled.   Specifying  a 0 value indicates use of the original bit
       depth.

       Example:

               `-p 8C,8C,8c`

       Clip all components of a 16 bit RGB image to 8 bits.

   -f, -force-rgb
       Force output image color space to RGB.  For  TIF/TIFF  or  PNG  output  formats,  the  ICC
       profile  will  be applied in this case - default behaviour is to stored the profile in the
       output file, if supported.

   -u, -upsample
       Sub-sampled components will be upsampled to image size.

   -s, -split-pnm
       Split output components into different files when writing to PNM.

   -X, -XML [output file name]
       Store XML metadata to file, if it exists in compressed file.  File name  will  be  set  to
       output file name + ".xml"

   -W, -logfile [output file name]
       Log to file.  File name will be set to output file name

   -H, -num_threads [number of threads]
       Number of threads used for T1 compression.  Default is total number of logical cores.

   -e, -Repetitions [number of repetitions]
       Number of repetitions, for either a single image, or a folder of images.  Default is 1.  0
       signifies unlimited repetitions.

   -g, -PluginPath [plugin path]
       Path to Grok plugin, which handles T1 decompression.  Default search path for plugin is in
       same folder as grk_decompress binary

   -G, -DeviceId [device ID]
       For  Grok  plugin  running on multi-GPU system.  Specifies which single GPU accelerator to
       run codec on.  If the flag is set to -1, all GPUs are used in round-robin scheduling.   If
       set to -2, then plugin is disabled and compression is done on the CPU.  Default value: 0.

FILES

ENVIRONMENT

BUGS

       See GitHub Issues: https://github.com/GrokImageCompression/grok/issues

AUTHOR

       Grok Image Compression Inc.

SEE ALSO

       grk_compress(1)