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/* yuvtoppm.c - convert Abekas YUV bytes into a portable pixmap
**
** by Marc Boucher
** Internet: marc@PostImage.COM
**
** Based on Example Conversion Program, A60/A64 Digital Video Interface
** Manual, page 69
**
** Uses integer arithmetic rather than floating point for better performance
**
** Copyright (C) 1991 by DHD PostImage Inc.
** Copyright (C) 1987 by Abekas Video Systems Inc.
** Copyright (C) 1991 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose 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 is provided "as is" without express or
** implied warranty.
*/
#include "pm_c_util.h"
#include "mallocvar.h"
#include "shhopt.h"
#include "ppm.h"
struct CmdlineInfo {
/* All the information the user supplied in the command line,
in a form easy for the program to use.
*/
unsigned int cols;
unsigned int rows;
const char * inputFileName; /* Name of input file */
};
static void
parseCommandLine(int argc, const char ** argv,
struct CmdlineInfo * const cmdlineP) {
optEntry * option_def;
optStruct3 opt;
unsigned int option_def_index;
MALLOCARRAY_NOFAIL(option_def, 100);
OPTENTINIT;
opt.opt_table = option_def;
opt.short_allowed = FALSE; /* We have no short (old-fashioned) options */
opt.allowNegNum = FALSE; /* We have no parms that are negative numbers */
pm_optParseOptions4(&argc, argv, opt, sizeof(opt), 0);
/* Uses and sets argc, argv, and some of *cmdlineP and others. */
if (argc-1 < 2)
pm_error("You need at least two arguments: width and height in "
"pixels. You specified %u", argc-1);
else {
int const widthArg = atoi(argv[1]);
int const heightArg = atoi(argv[2]);
if (widthArg < 0)
pm_error("Negative number for width: %d", widthArg);
if (heightArg < 0)
pm_error("Negative number for height: %d", heightArg);
cmdlineP->cols = widthArg;
cmdlineP->rows = heightArg;
if (cmdlineP->cols % 2 != 0)
pm_error("Number of columns (%u) is odd. "
"A YUV image must have an "
"even number of columns.", cmdlineP->cols);
if (argc-1 < 3)
cmdlineP->inputFileName = "-";
else {
cmdlineP->inputFileName = argv[3];
if (argc-1 > 3)
pm_error("Too many arguments: %u. "
"The only possible arguments are "
"width, height, and input file name", argc-1);
}
}
}
static int
limit(int const x) {
if (x > 0xffffff)
return 0xff;
else if (x <= 0xffff)
return 0;
else
return ((x >> 16) & 0xff);
}
static int
nonneg(int const x) {
/*----------------------------------------------------------------------------
Raise 'x' to 0 if negative
-----------------------------------------------------------------------------*/
return x < 0 ? 0 : x;
}
struct Yuv {
/*----------------------------------------------------------------------------
This is an element of a YUV file. It describes two side-by-side pixels.
This is the actual layout of the data in the file (4 bytes).
-----------------------------------------------------------------------------*/
unsigned char u;
unsigned char y1;
unsigned char v;
unsigned char y2;
};
static void
readYuv(FILE * const ifP,
struct Yuv * const yuvP) {
size_t readCt;
readCt = fread(yuvP, sizeof(*yuvP), 1, ifP);
if (readCt != 1) {
if (feof(ifP))
pm_error("Premature end of input.");
else
pm_error("Error reading input.");
}
}
static void
yuvtoppm(FILE * const ifP,
unsigned int const cols,
unsigned int const rows,
FILE * const ofP) {
pixval const maxval = 255;
pixel * pixrow;
unsigned int row;
ppm_writeppminit(ofP, cols, rows, maxval, 0);
pixrow = ppm_allocrow(cols);
for (row = 0; row < rows; ++row) {
unsigned int col;
for (col = 0; col < cols; col += 2) {
/* Produce two pixels in pixrow[] */
struct Yuv yuv;
int y1, u, v, y2, r, g, b;
readYuv(ifP, &yuv);
u = yuv.u - 128;
y1 = nonneg (yuv.y1 - 16);
v = yuv.v - 128;
y2 = nonneg (yuv.y2 - 16);
r = 104635 * v;
g = -25690 * u + -53294 * v;
b = 132278 * u;
y1 *= 76310;
y2 *= 76310;
PPM_ASSIGN(pixrow[col],
limit(r + y1), limit(g + y1), limit(b + y1));
PPM_ASSIGN(pixrow[col + 1],
limit(r + y2), limit(g + y2), limit(b + y2));
}
ppm_writeppmrow(ofP, pixrow, cols, maxval, 0);
}
ppm_freerow(pixrow);
if (fgetc(ifP) != EOF)
pm_message("Extraneous data at end of image.");
}
int
main (int argc, const char ** argv) {
FILE * ifP;
struct CmdlineInfo cmdline;
pm_proginit(&argc, argv);
parseCommandLine(argc, argv, &cmdline);
ifP = pm_openr(cmdline.inputFileName);
yuvtoppm(ifP, cmdline.cols, cmdline.rows, stdout);
pm_close(ifP);
pm_close(stdout);
return 0;
}
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