diff options
Diffstat (limited to 'src/extract_mpeg2.c')
| -rw-r--r-- | src/extract_mpeg2.c | 462 |
1 files changed, 462 insertions, 0 deletions
diff --git a/src/extract_mpeg2.c b/src/extract_mpeg2.c new file mode 100644 index 0000000..ba3c469 --- /dev/null +++ b/src/extract_mpeg2.c @@ -0,0 +1,462 @@ +/* + * extract_mpeg2.c + * 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 + */ + +#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 = 0xe0; +static int demux_pid = 0; +static int demux_pva = 0; + +static void print_usage (char ** argv) +{ + fprintf (stderr, "usage: %s [-h] [-s <track>] [-t <pid>] [-p] <file>\n" + "\t-h\tdisplay help\n" + "\t-s\tset track number (0-15 or 0xe0-0xef)\n" + "\t-t\tuse transport stream demultiplexer, pid 0x10-0x1ffe\n" + "\t-p\tuse pva demultiplexer\n", + argv[0]); + + exit (1); +} + +static void handle_args (int argc, char ** argv) +{ + int c; + char * s; + + while ((c = getopt (argc, argv, "hs:t:p")) != -1) + switch (c) { + case 's': + demux_track = strtol (optarg, &s, 0); + if (demux_track < 0xe0) + demux_track += 0xe0; + if (demux_track < 0xe0 || demux_track > 0xef || *s) { + fprintf (stderr, "Invalid track number: %s\n", optarg); + print_usage (argv); + } + break; + + case 't': + demux_pid = strtol (optarg, &s, 0); + if (demux_pid < 0x10 || demux_pid > 0x1ffe || *s) { + fprintf (stderr, "Invalid pid: %s\n", optarg); + print_usage (argv); + } + break; + + case 'p': + demux_pva = 1; + 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[264]; + + 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) { + if ((header[3] >= 0xe0) && (header[3] <= 0xef)) + goto pes; + 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 (5); + 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 */ + NEEDBYTES (12); + DONEBYTES (12); + /* header points to the mpeg1 pack header */ + } else { + fprintf (stderr, "weird pack header\n"); + DONEBYTES (5); + } + break; + default: + if (header[3] == demux_track) { + pes: + NEEDBYTES (7); + if ((header[6] & 0xc0) == 0x80) { /* mpeg2 */ + NEEDBYTES (9); + len = 9 + 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]; + NEEDBYTES (len); + /* header points to the mpeg1 pes header */ + } + 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; + } else if (header[3] < 0xb9) { + fprintf (stderr, + "looks like a video stream, not system stream\n"); + DONEBYTES (4); + } else { + NEEDBYTES (6); + DONEBYTES (6); + bytes = (header[4] << 8) + header[5]; + 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 int pva_demux (uint8_t * buf, uint8_t * end) +{ + static int state = DEMUX_SKIP; + static int state_bytes = 0; + static uint8_t head_buf[12]; + + uint8_t * header; + int bytes; + int len; + + switch (state) { + case DEMUX_HEADER: + if (state_bytes > 0) { + header = head_buf; + bytes = state_bytes; + goto continue_header; + } + break; + case DEMUX_DATA: + if (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 (state_bytes > end - buf) { + state_bytes -= end - buf; + return 0; + } + buf += state_bytes; + break; + } + + while (1) { + payload_start: + header = buf; + bytes = end - buf; + continue_header: + NEEDBYTES (2); + if (header[0] != 0x41 || header[1] != 0x56) { + if (header != head_buf) { + buf++; + goto payload_start; + } else { + header[0] = header[1]; + bytes = 1; + goto continue_header; + } + } + NEEDBYTES (8); + if (header[2] != 1) { + DONEBYTES (8); + bytes = (header[6] << 8) + header[7]; + if (bytes > end - buf) { + state = DEMUX_SKIP; + state_bytes = bytes - (end - buf); + return 0; + } + buf += bytes; + } else { + len = 8; + if (header[5] & 0x10) { + len = 12; + NEEDBYTES (len); + } + DONEBYTES (len); + bytes = (header[6] << 8) + header[7] + 8 - len; + if (bytes > end - buf) { + fwrite (buf, end - buf, 1, stdout); + state = DEMUX_DATA; + state_bytes = bytes - (end - buf); + return 0; + } else if (bytes > 0) { + fwrite (buf, bytes, 1, stdout); + buf += bytes; + } + } + } +} + +static void pva_loop (void) +{ + uint8_t * end; + + do { + end = buffer + fread (buffer, 1, BUFFER_SIZE, in_file); + pva_demux (buffer, end); + } while (end == buffer + BUFFER_SIZE); +} + +static void ts_loop (void) +{ + uint8_t * buf; + uint8_t * nextbuf; + uint8_t * data; + uint8_t * end; + int pid; + + buf = buffer; + while (1) { + end = buf + fread (buf, 1, buffer + BUFFER_SIZE - buf, in_file); + buf = buffer; + for (; (nextbuf = buf + 188) <= end; buf = nextbuf) { + if (*buf != 0x47) { + fprintf (stderr, "bad sync byte\n"); + nextbuf = buf + 1; + continue; + } + 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 > nextbuf) + continue; + } + if (buf[3] & 0x10) + demux (data, nextbuf, + (buf[1] & 0x40) ? DEMUX_PAYLOAD_START : 0); + } + if (end != buffer + BUFFER_SIZE) + break; + memcpy (buffer, buf, end - buf); + buf = buffer + (end - buf); + } +} + +int main (int argc, char ** argv) +{ +#ifdef HAVE_IO_H + setmode (fileno (stdin), O_BINARY); + setmode (fileno (stdout), O_BINARY); +#endif + + handle_args (argc, argv); + + if (demux_pva) + pva_loop (); + if (demux_pid) + ts_loop (); + else + ps_loop (); + + return 0; +} |