PNMTOLJPG(1)					     PNMTOLJPG(1)


NAME
       pnmtoljpg - compress a Portable Pixmap or Portable Graymap
       image file to a lossless JPEG file

SYNOPSIS
       pnmtoljpg [ -d ] [ -h ] [ -p# ] [ -r# ] [ -s{1..7} ] [  -v
       ] [ filename ...	 ]


DESCRIPTION
       pnmtoljpg  compresses  a	 PPM  (Portable	 Pixmap) or a PGM
       (Portable Graymap) image, and  produces	a  lossless  JPEG
       (LJPG) file. If no files are specified, the standard input
       is compressed to the standard output.

OPTIONS
       -d     Use default Huffman table.  If  this  flag  is  not
	      specified, pnmtoljpg will generate an optimal Huff-
	      man table.

       -h --help
	      Display a help screen and quit.

       -p#    The #, an integer less than sample precision  bits,
	      is the point tranform parameter.

       -r#    Restart at every # row(s).

       -s{1..7}
	      Supply  a	 prediction  selection	value  (PSV) set,
	      {1..7}. The pnmtoljpg tries all PSVs in the set and
	      select  the best one. A PSV is an integer between 1
	      and 7 inclusively. If a "-s" flag is not	provided,
	      pnmtoljpg will try all seven PSVs.

       -v verbose
	      Display data about image format, image size, sample
	      precision,  total	 bytes	category  symbols,  total
	      bytes  of	 additional  symbols,  original	 and com-
	      pressed file size, and compress ratio.

EXAMPLES
       This example compresses a PPM file  foo.ppm  with  optimal
       Huffman	table  and  the	 default  PSV  set. The output is
       foo.ljpg.

	      pnmtoljpg foo.ppm foo.ljpg

       Next example compresses a PGM file  foo.pgm  with  default
       Huffman	table and PSV 4. The output is saved as foo.ljpg.

	      pnmtoljpg -d -s4 < foo.ppm > foo.ljpg

       The last	 example  compresses  a	 PPM  file  foo.ppm  with



			   14 June 1994				1





PNMTOLJPG(1)					     PNMTOLJPG(1)


       optimal	Huffman	 table	and  a PSV set {246}. The verbose
       flag is on, and the output is saved as foo.ljpg.

	      pnmtoljpg -v -s246 foo.ppm > foo.ljpg

SEE ALSO
       ljpgtopnm(1), ppm(5), pgm(5)
       Wallace, Gregory K.  "The JPEG Still  Picture  Compression
       Standard", Communications of the ACM, April 1991 (vol. 34,
       no. 4), pp. 30-44.

AUTHOR
       Kongji Huang and Brian Smith

BUGS
       Arithmetic coding and multiple scans are not supported.

       Comments in PPM/PGM files  are  not  stored  in	the  LJPG
       files.






































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