1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
|
/* 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 "ppm.h"
#include "mallocvar.h"
/* x must be signed for the following to work correctly */
#define limit(x) ((((x)>0xffffff)?0xff0000:(((x)<=0xffff)?0:(x)&0xff0000))>>16)
int
main(argc, argv)
char **argv;
{
FILE *ifp;
pixel *pixrow;
int argn, rows, cols, row;
const char * const usage = "<width> <height> [yuvfile]";
struct yuv {
/* This is an element of a YUV file. It describes two
side-by-side pixels.
*/
unsigned char u;
unsigned char y1;
unsigned char v;
unsigned char y2;
} *yuvbuf;
ppm_init(&argc, argv);
argn = 1;
if (argn + 2 > argc)
pm_usage(usage);
cols = atoi(argv[argn++]);
rows = atoi(argv[argn++]);
if (cols <= 0 || rows <= 0)
pm_usage(usage);
if (argn < argc) {
ifp = pm_openr(argv[argn]);
++argn;
} else
ifp = stdin;
if (argn != argc)
pm_usage(usage);
if (cols % 2 != 0) {
pm_error("Number of columns (%d) is odd. A YUV image must have an "
"even number of columns.", cols);
}
ppm_writeppminit(stdout, cols, rows, (pixval) 255, 0);
pixrow = ppm_allocrow(cols);
MALLOCARRAY(yuvbuf, (cols+1)/2);
if (yuvbuf == NULL)
pm_error("Unable to allocate YUV buffer for %d columns.", cols);
for (row = 0; row < rows; ++row) {
int col;
fread(yuvbuf, cols * 2, 1, ifp);
for (col = 0; col < cols; col += 2) {
/* Produce two pixels in pixrow[] */
int y1, u, v, y2, r, g, b;
u = yuvbuf[col/2].u-128;
y1 = yuvbuf[col/2].y1 - 16;
if (y1 < 0) y1 = 0;
v = yuvbuf[col/2].v - 128;
y2 = yuvbuf[col/2].y2 - 16;
if (y2 < 0) y2 = 0;
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(stdout, pixrow, cols, (pixval) 255, 0);
}
free(yuvbuf);
ppm_freerow(pixrow);
pm_close(ifp);
pm_close(stdout);
exit(0);
}
|
