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
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
/*
* sample6.c
* Copyright (C) 2003 Regis Duchesne <hpreg@zoy.org>
* Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
*
* This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
* See http://libmpeg2.sourceforge.net/ for updates.
*
* mpeg2dec is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* mpeg2dec is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* This program reads a MPEG-2 stream, and saves each of its frames as
* an image file using the PPM format (color).
*
* It demonstrates how to use the following features of libmpeg2:
* - Output buffers use the RGB 24-bit chunky format.
* - Output buffers are allocated and managed by the caller.
*/
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include "mpeg2.h"
#include "mpeg2convert.h"
static void save_ppm (int width, int height, uint8_t * buf, int num)
{
char filename[100];
FILE * ppmfile;
sprintf (filename, "%d.ppm", num);
ppmfile = fopen (filename, "wb");
if (!ppmfile) {
fprintf (stderr, "Could not open file \"%s\".\n", filename);
exit (1);
}
fprintf (ppmfile, "P6\n%d %d\n255\n", width, height);
fwrite (buf, 3 * width, height, ppmfile);
fclose (ppmfile);
}
static struct fbuf_s {
uint8_t * rgb[3];
int used;
} fbuf[3];
static struct fbuf_s * get_fbuf (void)
{
int i;
for (i = 0; i < 3; i++)
if (!fbuf[i].used) {
fbuf[i].used = 1;
return fbuf + i;
}
fprintf (stderr, "Could not find a free fbuf.\n");
exit (1);
}
static void sample6 (FILE * mpgfile)
{
#define BUFFER_SIZE 4096
uint8_t buffer[BUFFER_SIZE];
mpeg2dec_t * decoder;
const mpeg2_info_t * info;
mpeg2_state_t state;
size_t size;
int framenum = 0;
int pixels;
int i;
struct fbuf_s * current_fbuf;
decoder = mpeg2_init ();
if (decoder == NULL) {
fprintf (stderr, "Could not allocate a decoder object.\n");
exit (1);
}
info = mpeg2_info (decoder);
size = (size_t)-1;
do {
state = mpeg2_parse (decoder);
switch (state) {
case STATE_BUFFER:
size = fread (buffer, 1, BUFFER_SIZE, mpgfile);
mpeg2_buffer (decoder, buffer, buffer + size);
break;
case STATE_SEQUENCE:
mpeg2_convert (decoder, mpeg2convert_rgb24, NULL);
mpeg2_custom_fbuf (decoder, 1);
pixels = info->sequence->width * info->sequence->height;
for (i = 0; i < 3; i++) {
fbuf[i].rgb[0] = (uint8_t *) malloc (3 * pixels);
fbuf[i].rgb[1] = fbuf[i].rgb[2] = NULL;
if (!fbuf[i].rgb[0]) {
fprintf (stderr, "Could not allocate an output buffer.\n");
exit (1);
}
fbuf[i].used = 0;
}
for (i = 0; i < 2; i++) {
current_fbuf = get_fbuf ();
mpeg2_set_buf (decoder, current_fbuf->rgb, current_fbuf);
}
break;
case STATE_PICTURE:
current_fbuf = get_fbuf ();
mpeg2_set_buf (decoder, current_fbuf->rgb, current_fbuf);
break;
case STATE_SLICE:
case STATE_END:
case STATE_INVALID_END:
if (info->display_fbuf)
save_ppm (info->sequence->width, info->sequence->height,
info->display_fbuf->buf[0], framenum++);
if (info->discard_fbuf)
((struct fbuf_s *)info->discard_fbuf->id)->used = 0;
if (state != STATE_SLICE)
for (i = 0; i < 3; i++)
free (fbuf[i].rgb[0]);
break;
default:
break;
}
} while (size);
mpeg2_close (decoder);
}
int main (int argc, char ** argv)
{
FILE * mpgfile;
if (argc > 1) {
mpgfile = fopen (argv[1], "rb");
if (!mpgfile) {
fprintf (stderr, "Could not open file \"%s\".\n", argv[1]);
exit (1);
}
} else
mpgfile = stdin;
sample6 (mpgfile);
return 0;
}
|
