/* * 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 4096static 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 1static 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;}