/*
* extract_a52.c
* Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
* Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
*
* This file is part of a52dec, a free ATSC A-52 stream decoder.
* See http://liba52.sourceforge.net/ for updates.
*
* a52dec 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.
*
* a52dec 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
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <getopt.h>
#ifdef HAVE_IO_H
#include <fcntl.h>
#include <io.h>
#endif
#include <inttypes.h>
#define BUFFER_SIZE 4096
static uint8_t buffer[BUFFER_SIZE];
static FILE * in_file;
static int demux_track = 0x80;
static int demux_pid = 0;
static void print_usage (char ** argv)
{
fprintf (stderr, "usage: %s [-s <track>] [-t <pid>] <file>\n"
"\t-s\tset track number (0-7 or 0x80-0x87)\n"
"\t-t\tuse transport stream demultiplexer, pid 0x10-0x1ffe\n",
argv[0]);
exit (1);
}
static void handle_args (int argc, char ** argv)
{
int c;
char * s;
while ((c = getopt (argc, argv, "s:t:")) != -1)
switch (c) {
case 's':
demux_track = strtol (optarg, &s, 16);
if (demux_track < 0x80)
demux_track += 0x80;
if ((demux_track < 0x80) || (demux_track > 0x87) || (*s)) {
fprintf (stderr, "Invalid track number: %s\n", optarg);
print_usage (argv);
}
break;
case 't':
demux_pid = strtol (optarg, &s, 16);
if ((demux_pid < 0x10) || (demux_pid > 0x1ffe) || (*s)) {
fprintf (stderr, "Invalid pid: %s\n", optarg);
print_usage (argv);
}
break;
default:
print_usage (argv);
}
if (optind < argc) {
in_file = fopen (argv[optind], "rb");
if (!in_file) {
fprintf (stderr, "%s - could not open file %s\n", strerror (errno),
argv[optind]);
exit (1);
}
} else
in_file = stdin;
}
#define DEMUX_PAYLOAD_START 1
static int demux (uint8_t * buf, uint8_t * end, int flags)
{
static int mpeg1_skip_table[16] = {
0, 0, 4, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
/*
* the demuxer keeps some state between calls:
* if "state" = DEMUX_HEADER, then "head_buf" contains the first
* "bytes" bytes from some header.
* if "state" == DEMUX_DATA, then we need to copy "bytes" bytes
* of ES data before the next header.
* if "state" == DEMUX_SKIP, then we need to skip "bytes" bytes
* of data before the next header.
*
* NEEDBYTES makes sure we have the requested number of bytes for a
* header. If we dont, it copies what we have into head_buf and returns,
* so that when we come back with more data we finish decoding this header.
*
* DONEBYTES updates "buf" to point after the header we just parsed.
*/
#define DEMUX_HEADER 0
#define DEMUX_DATA 1
#define DEMUX_SKIP 2
static int state = DEMUX_SKIP;
static int state_bytes = 0;
static uint8_t head_buf[268];
uint8_t * header;
int bytes;
int len;
#define NEEDBYTES(x) \
do { \
int missing; \
\
missing = (x) - bytes; \
if (missing > 0) { \
if (header == head_buf) { \
if (missing <= end - buf) { \
memcpy (header + bytes, buf, missing); \
buf += missing; \
bytes = (x); \
} else { \
memcpy (header + bytes, buf, end - buf); \
state_bytes = bytes + end - buf; \
return 0; \
} \
} else { \
memcpy (head_buf, header, bytes); \
state = DEMUX_HEADER; \
state_bytes = bytes; \
return 0; \
} \
} \
} while (0)
#define DONEBYTES(x) \
do { \
if (header != head_buf) \
buf = header + (x); \
} while (0)
if (flags & DEMUX_PAYLOAD_START)
goto payload_start;
switch (state) {
case DEMUX_HEADER:
if (state_bytes > 0) {
header = head_buf;
bytes = state_bytes;
goto continue_header;
}
break;
case DEMUX_DATA:
if (demux_pid || (state_bytes > end - buf)) {
fwrite (buf, end - buf, 1, stdout);
state_bytes -= end - buf;
return 0;
}
fwrite (buf, state_bytes, 1, stdout);
buf += state_bytes;
break;
case DEMUX_SKIP:
if (demux_pid || (state_bytes > end - buf)) {
state_bytes -= end - buf;
return 0;
}
buf += state_bytes;
break;
}
while (1) {
if (demux_pid) {
state = DEMUX_SKIP;
return 0;
}
payload_start:
header = buf;
bytes = end - buf;
continue_header:
NEEDBYTES (4);
if (header[0] || header[1] || (header[2] != 1)) {
if (demux_pid) {
state = DEMUX_SKIP;
return 0;
} else if (header != head_buf) {
buf++;
goto payload_start;
} else {
header[0] = header[1];
header[1] = header[2];
header[2] = header[3];
bytes = 3;
goto continue_header;
}
}
if (demux_pid && (header[3] != 0xbd)) {
fprintf (stderr, "bad stream id %x\n", header[3]);
exit (1);
}
switch (header[3]) {
case 0xb9: /* program end code */
/* DONEBYTES (4); */
/* break; */
return 1;
case 0xba: /* pack header */
NEEDBYTES (12);
if ((header[4] & 0xc0) == 0x40) { /* mpeg2 */
NEEDBYTES (14);
len = 14 + (header[13] & 7);
NEEDBYTES (len);
DONEBYTES (len);
/* header points to the mpeg2 pack header */
} else if ((header[4] & 0xf0) == 0x20) { /* mpeg1 */
DONEBYTES (12);
/* header points to the mpeg1 pack header */
} else {
fprintf (stderr, "weird pack header\n");
exit (1);
}
break;
case 0xbd: /* private stream 1 */
NEEDBYTES (7);
if ((header[6] & 0xc0) == 0x80) { /* mpeg2 */
NEEDBYTES (9);
len = 10 + header[8];
NEEDBYTES (len);
/* header points to the mpeg2 pes header */
} else { /* mpeg1 */
len = 7;
while ((header-1)[len] == 0xff) {
len++;
NEEDBYTES (len);
if (len == 23) {
fprintf (stderr, "too much stuffing\n");
break;
}
}
if (((header-1)[len] & 0xc0) == 0x40) {
len += 2;
NEEDBYTES (len);
}
len += mpeg1_skip_table[(header - 1)[len] >> 4] + 1;
NEEDBYTES (len);
/* header points to the mpeg1 pes header */
}
if ((!demux_pid) && ((header-1)[len] != demux_track)) {
DONEBYTES (len);
bytes = 6 + (header[4] << 8) + header[5] - len;
if (bytes <= 0)
continue;
goto skip;
}
len += 3;
NEEDBYTES (len);
DONEBYTES (len);
bytes = 6 + (header[4] << 8) + header[5] - len;
if (demux_pid || (bytes > end - buf)) {
fwrite (buf, end - buf, 1, stdout);
state = DEMUX_DATA;
state_bytes = bytes - (end - buf);
return 0;
} else if (bytes <= 0)
continue;
fwrite (buf, bytes, 1, stdout);
buf += bytes;
break;
default:
if (header[3] < 0xb9) {
fprintf (stderr,
"looks like a video stream, not system stream\n");
exit (1);
} else {
NEEDBYTES (6);
DONEBYTES (6);
bytes = (header[4] << 8) + header[5];
skip:
if (bytes > end - buf) {
state = DEMUX_SKIP;
state_bytes = bytes - (end - buf);
return 0;
}
buf += bytes;
}
}
}
}
static void ps_loop (void)
{
uint8_t * end;
do {
end = buffer + fread (buffer, 1, BUFFER_SIZE, in_file);
if (demux (buffer, end, 0))
break; /* hit program_end_code */
} while (end == buffer + BUFFER_SIZE);
}
static void ts_loop (void)
{
#define PACKETS (BUFFER_SIZE / 188)
uint8_t * buf;
uint8_t * data;
uint8_t * end;
int packets;
int i;
int pid;
do {
packets = fread (buffer, 188, PACKETS, in_file);
for (i = 0; i < packets; i++) {
buf = buffer + i * 188;
end = buf + 188;
if (buf[0] != 0x47) {
fprintf (stderr, "bad sync byte\n");
exit (1);
}
pid = ((buf[1] << 8) + buf[2]) & 0x1fff;
if (pid != demux_pid)
continue;
data = buf + 4;
if (buf[3] & 0x20) { /* buf contains an adaptation field */
data = buf + 5 + buf[4];
if (data > end)
continue;
}
if (buf[3] & 0x10)
demux (data, end, (buf[1] & 0x40) ? DEMUX_PAYLOAD_START : 0);
}
} while (packets == PACKETS);
}
int main (int argc, char ** argv)
{
#ifdef HAVE_IO_H
setmode (fileno (stdout), O_BINARY);
#endif
handle_args (argc, argv);
if (demux_pid)
ts_loop ();
else
ps_loop ();
return 0;
}