.TH pcdtoppm 1 "3 March 1994"
.IX pcdtoppm
.IX PhotoCD
.SH NAME
pcdtoppm - convert a PhotoCD file into a portable pixmap file
.SH SYNOPSIS
.B pcdtoppm
.RB [ -c0 ]
.RB [ -c- ]
.RB [ -c+ ]
.RB [ -crop ]
.RB [ -pos ]
.RB [ -rep ]
.RB [ -s ]
.RB [ -x ]
.RB [ -1 | -Base/16
.RI | -128x192 ]
.RB [ -2 | -Base/4
.RI | -256x384 ]
.RB [ -3 | -Base
.RI | -512x768 ]
.RB [ -4 | -4Base
.RI | -1024x1536 ]
.RB [ -5 | -16Base
.RI | -2048x3072 ]
.RB [ -6 | -64Base
.RI | -4096x6144 ]
.RI [ infile ]
.SH DESCRIPTION
This program accepts PhotoCD image or overview file data from the specified
input file,
.I infile
(or, if the filename is missing and the resolution is lower than 64Base,
from standard input),
and writes Portable Pixmap Format to standard output.
.LP
On a standard PhotoCD,
image files appear in
.IR PHOTO_CD/IMAGES ,
where they appear in files with names of the form
.IR IMGnnnn.PCD ,
where
.I nnnn
is a 4-digit-number.
The overview file appears in
.IR PHOTO_CD/OVERVIEW.PCD .
.LP
PhotoCD images are stored using as many as 6 different resolutions:
.ta 1i 3i
.nf
	Format	Resolution
	------	----------
	64Base	4096x6144 (ProPhotoCD only)
	16Base	2048x3072
	4Base	1024x1536
	Base	512x768
	Base/4	256x384
	Base/16	128x192
.fi
.LP
The overview file employs Base/16 format.
.SH OPTIONS
Invoking
.I pcdtoppm
without arguments produces a list of default values.
Note that you can supply only one size option.
.TP
.B -c0
Do not correct (brighten or darken) the image.
.TP
.B -c-
Darken the image.
.TP
.B -c+
Brighten the image.
.TP
.B -crop
Cut off the black frame which sometimes appears
at the image borders.
.TP
.B -pos
Print the relative starting position of the data for the current resolution.
.TP
.B -rep
Try to jump over reading errors in the Huffman code. 
.TP
.B -s
Apply a simple sharpness operator to the luminosity channel.
.TP
.B -x
Overskip Mode (applicable to Base/16, Base/4, Base and 4Base).
In PhotoCD images the luminosity channel is stored in full resolution,
the two chromaticity channels are stored in half resolution only and have
to be interpolated.
In Overskip Mode,
the chromaticity channels of the next higher resolution are
taken instead of interpolating.
To see the difference,
generate one
.I ppm
with and one
.I ppm
without this flag.
Use
.IR pnmarith (1)
to generate the difference image of these two images.
Call
.IR ppmhist (1)
for this difference or show it with
.IR xv (1)
(push the
.B HistEq
button in the color editor).
.TP
.BR -1 | -Base/16 | -128x192
Extract the Base/16 image.
.TP
.B -2 | -Base/4 | -256x384
Extract the Base/4 image.
.TP
.B -3 | -Base | -512x768
Extract the Base image.
.TP
.B -4 | -4Base | -1024x1536
Extract the 4Base image.
.TP
.B -5 | -16Base | -2048x3072
Extract the 16Base image.
.TP
.B -6 | -64Base | -4096x6144
Extract the 64Base image. This resolution can be extracted from
ProPhotoCD images only. The path of the 64Base extension files is
derived from the path to the image file. This means that it doesn't work
on stdin an the directory structure must be the very same as on the
ProPhotoCD.
.SH BUGS
.LP
Available information obout the PhotoCD format is vague;
this program was developed by trial-and-error after staring at hex-dumps.
Please send bugs reports and patches to the author.
.SH "SEE ALSO"
pnmarith(1),
pbmplus(1),
ppmhist(1),
ppmquant(1),
ppmtopgm(1),
ppmtorgb3(1),
xv(1)
.SH AUTHOR
Based on hpcdtoppm 0.6, which is:
Copyright (c) 1992, 1993, 1994 by Hadmut Danisch (danisch@ira.uka.de).
This software is not public domain.
Permission to use and distribute this software and its
documentation for noncommercial use and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation.
This software may not be sold or used for profit-making activities.
.LP
Manual page extensively modified by R. P. C. Rodgers (rodgers@nlm.nih.gov).