COMPILATION INSTRUCTIONS: 1. Unpack archive. 2. Run make clean "name", where "name" is loco -- for encoder/decoder This program supports: "8 bit" images with 8 bits per color component or less. "16 bit" images with between 9 and 16 bits per color component. component. 3. Executable for compressor is "locoe," decompressor is "locod". USAGE: General remarks for multiple-component images: a) Encoder input (uncompressed) or decoder output (decompressed) images are in either PGM (grayscale) or PPM (3-color) format. This is of course NOT part of the JPEG-LS standard, and these input/output formats were selected for this implementation only. These formats have an ASCII header consisting of 3 lines of the following form * PGM (single component): P5 cols rows maxval * PPM (3 components) P6 cols rows maxval For PGM, the header is followed by cols*rows samples in binary format, where cols and rows are the number of columns and rows, respectively. A test image "cmpnd2g.pgm" is included in the archive. Samples have 8 bits if maxval < 256, or 16 bits if 256 <= maxval < 65536. For PPM, the header is followed by cols*rows TRIPLETS of symbols in binary format. Each symbol in a triplet represents a color plane value (viewers usually interpret PPM triplets as RGB). For more than 3 components, the PPM output file format is extended to arbitrary m-tuples, where m is the number of components. The first row of the header is Px, where x = 10+m (e.g. P15 for a 5-component image). P5 (m=1), P6 (m=3), and P7 (m=4) are used, in addition to P11, P13, and P14, respectively. A multi-component image can be specified to the encoder either as a list of PGM files (each representing a color plane), or a single PPM-type file. b) Three modes of operation are supported for multi-component images (images of the type RGB, CMYK, YUV, etc). We briefly describe them now, for details see the JPEG-LS Working Draft document. * Plane-interleaved. The image components are compressed one after the other, in a completely independent form. Only multiple input (one PGM file per plane) in the encoder, and multiple output (one PGM file per plane) in the decoder are supported in this mode. This mode also works when m=1. * Line-interleaved. One row per image component is processed at a time, in an interleaved form. Common context statistics for all the components are used in this mode, and is plane independent otherwise. Both multiple PGM and single PPM input (output) are supported in the encoder (decoder). Line-interleaved mode is the default mode of the encoder. This mode also works when m=1. * Sample-interleaved mode. One sample per image component is processed at a time, using common statistics. Only single PPM input and single PPM output are supported in this mode. c) Which of the three multi-components modes runs faster depends on the specific system (UNIX or PC). For the line interleaved mode, the processing time relation between the single and the multiple files input/output depends on the system as well. d) Sub-sampled components can be specified to the encoder (e.g., a YUV representation with the U and V components having a fraction of the number of columns of the Y component). For sub-sampled files, the input to the encoder must be given as a series of PGM files in non-increasing order of size. Sample-interleaved mode is not supported for images with sub-sampled components. e) The output of the encoder, and input to the decoder, is always a unique JPEG-LS compressed file, independently of the number of image components. All the image components share the same header in JPEG-LS. COMMAND LINES: encoder: locoe [flags] infile1 [infile2,infile3,...] [-ooutfile] DEFAULTS: infile1 : must be in PGM or PPM format infile2,... : additional input files for Plane Interleaved or Line Interleaved modes. Must be in PGM (P5) format outfile : default is locoe.out FLAGS, PARAMETERS: -i : alternate input-specification, use -i- for stdin -o : output specification, use -o- for stdout -c : mode for multi-component images: 0: plane interleaved 1: line interleaved (Default) 2: sample interleaved -n or -e : Max allowed loss per symbol (default = 0, lossless). -h : print help Remarks: The following optional flags allow specification of parameters in the algorithm. These parameters, if not default, are included in the JPEG-LS header, and are part of the standard. Please refer to Working Document for details. -r : RESET (if not compiled with FIXRESET, see below) -S : Context modeling thresholds -m : Use mapping table where
is a file in the format: 1st byte of
is the Table ID, 2nd byte of
is the Width of each table entry (in bytes), 3rd - 6th byte of
is the Max Table Index Value specified as an integer (4 bytes), 7th byte and on are the table entries. -t : Use Restart Markers where is the restart interval (ie. number of MCU's between restart markers).\n"); *** Use only if you know what you are doing! decoder: locod [flags] [infile] [outfile1 [outfile2, ...]] DEFAULTS: infile = locoe.out outfile1 = locod.out for single output file outfile[1,2,...] = locod[1,2,...].out for multiple output files in Plane or Line Interleaved mode FLAGS, PARAMETERS: outfile2, ... : multiple output specification for plane- or line-interleaved mode -i : alternate input specification, use -i- for stdin -o : alternate output specification, use -o- for stdout -P : generate single (.ppm) output file for sample/line-int. mode. Mandatory for sample-int. mode. EXAMPLES: For the examples, assume: * red.pgm, green.pgm, and blue.pgm are 3 color components of a color image, of the same size. * color.ppm is the color image corresponding to red.pgm, green.pgm, blue.pgm * hotely.pgm, hotelu.pgm, hotelv.pgm are 3 components of a color image sub-sampled in the horizontal direction 2:1:1 a) locoe red.pgm green.pgm blue.pgm Compresses the three files using the default color mode (line int., c=1) Compressed file is in locoe.out locod Decompresses locoe.out into 3 pgm files: locod1.out, locod2.out, locod3.out locod locoe.out a.pgm b.pgm c.pgm Decompresses locoe.out into 3 pgm files: a.pgm, b.pgm, c.pgm locod -P Decompresses locoe.out into one ppm file: locod.out b) locoe color.ppm Same as (a), using single input c) locoe -c0 red.pgm green.pgm blue.pgm Compresses the three files using the plane interleaved color mode locod Decompresses locoe.out into 3 pgm files: locod1.out, locod2.out, locod3.out In this case, since c=0, the command locod -P will give an error. d) locoe -c2 color.ppm Compresses color.ppm with sample int. mode. Note that only one (ppm) input file must be given in this mode. Output is in locoe.out locod -P Decompresses locoe.out into locod.out. Note that -P must be given, since for sample int. mode, only single output file is supported. g) locoe -Sa5 -Sb9 red.pgm Compress red.pgm with Sa=5, Sb=9, and Sc=DEFAULT h) locoe -r128 green.pgm Compresses green.pgm with RESET=128. OTHER CAVEATS, LIMITATIONS, ANNOYANCES, BUGS (?) ================================================= * The makefiles included in this version are very simple and could lead to a slower executable files than HP executables. * Annoyance: no spaces are allowed between flags and their arguments. This will be fixed in a future version. * Other bugs, annoyances: you tell us. ------------------------------------------------------------------------------ Feedback to ----------- The SPMG lab at the University of British Columbia: ismaeil R. Ismaeil ismail@ee.ubc.ca Dr. Faouzi Kossentini faouzi@ece.ubc.ca, or