ffmpeg/libavformat/mpeg.c
Paul Kelly 3dea63bd7e user specifyable maximum amount of memory to use for the index.
patch by Paul Kelly  paul stjohnspoint co uk
with some changes by me

Originally committed as revision 11521 to svn://svn.ffmpeg.org/ffmpeg/trunk
2008-01-13 13:33:37 +00:00

580 lines
17 KiB
C

/*
* MPEG1/2 demuxer
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "mpeg.h"
//#define DEBUG_SEEK
#undef NDEBUG
#include <assert.h>
/*********************************************/
/* demux code */
#define MAX_SYNC_SIZE 100000
static int check_pes(uint8_t *p, uint8_t *end){
int pes1;
int pes2= (p[3] & 0xC0) == 0x80
&& (p[4] & 0xC0) != 0x40
&&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));
for(p+=3; p<end && *p == 0xFF; p++);
if((*p&0xC0) == 0x40) p+=2;
if((*p&0xF0) == 0x20){
pes1= p[0]&p[2]&p[4]&1;
p+=5;
}else if((*p&0xF0) == 0x30){
pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;
p+=10;
}else
pes1 = *p == 0x0F;
return pes1||pes2;
}
static int mpegps_probe(AVProbeData *p)
{
uint32_t code= -1;
int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;
int i;
int score=0;
for(i=0; i<p->buf_size; i++){
code = (code<<8) + p->buf[i];
if ((code & 0xffffff00) == 0x100) {
int pes= check_pes(p->buf+i, p->buf+p->buf_size);
if(code == SYSTEM_HEADER_START_CODE) sys++;
else if(code == PRIVATE_STREAM_1) priv1++;
else if(code == PACK_START_CODE) pspack++;
else if((code & 0xf0) == VIDEO_ID && pes) vid++;
else if((code & 0xe0) == AUDIO_ID && pes) audio++;
else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;
else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;
}
}
if(vid+audio > invalid) /* invalid VDR files nd short PES streams */
score= AVPROBE_SCORE_MAX/4;
//av_log(NULL, AV_LOG_ERROR, "%d %d %d %d %d len:%d\n", sys, priv1, pspack,vid, audio, p->buf_size);
if(sys>invalid && sys*9 <= pspack*10)
return AVPROBE_SCORE_MAX/2+2; // +1 for .mpg
if(priv1 + vid + audio > invalid && (priv1+vid+audio)*9 <= pspack*10)
return AVPROBE_SCORE_MAX/2+2; // +1 for .mpg
if((!!vid ^ !!audio) && (audio+vid > 1) && !sys && !pspack && p->buf_size>2048) /* PES stream */
return AVPROBE_SCORE_MAX/2+2;
//02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1
return score;
}
typedef struct MpegDemuxContext {
int32_t header_state;
unsigned char psm_es_type[256];
int sofdec;
} MpegDemuxContext;
static int mpegps_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
MpegDemuxContext *m = s->priv_data;
const char *sofdec = "Sofdec";
int v, i = 0;
m->header_state = 0xff;
s->ctx_flags |= AVFMTCTX_NOHEADER;
m->sofdec = -1;
do {
v = get_byte(s->pb);
m->header_state = m->header_state << 8 | v;
m->sofdec++;
} while (v == sofdec[i] && i++ < 6);
/* no need to do more */
return 0;
}
static int64_t get_pts(ByteIOContext *pb, int c)
{
uint8_t buf[5];
buf[0] = c<0 ? get_byte(pb) : c;
get_buffer(pb, buf+1, 4);
return ff_parse_pes_pts(buf);
}
static int find_next_start_code(ByteIOContext *pb, int *size_ptr,
int32_t *header_state)
{
unsigned int state, v;
int val, n;
state = *header_state;
n = *size_ptr;
while (n > 0) {
if (url_feof(pb))
break;
v = get_byte(pb);
n--;
if (state == 0x000001) {
state = ((state << 8) | v) & 0xffffff;
val = state;
goto found;
}
state = ((state << 8) | v) & 0xffffff;
}
val = -1;
found:
*header_state = state;
*size_ptr = n;
return val;
}
#if 0 /* unused, remove? */
/* XXX: optimize */
static int find_prev_start_code(ByteIOContext *pb, int *size_ptr)
{
int64_t pos, pos_start;
int max_size, start_code;
max_size = *size_ptr;
pos_start = url_ftell(pb);
/* in order to go faster, we fill the buffer */
pos = pos_start - 16386;
if (pos < 0)
pos = 0;
url_fseek(pb, pos, SEEK_SET);
get_byte(pb);
pos = pos_start;
for(;;) {
pos--;
if (pos < 0 || (pos_start - pos) >= max_size) {
start_code = -1;
goto the_end;
}
url_fseek(pb, pos, SEEK_SET);
start_code = get_be32(pb);
if ((start_code & 0xffffff00) == 0x100)
break;
}
the_end:
*size_ptr = pos_start - pos;
return start_code;
}
#endif
/**
* Extracts stream types from a program stream map
* According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35
*
* @return number of bytes occupied by PSM in the bitstream
*/
static long mpegps_psm_parse(MpegDemuxContext *m, ByteIOContext *pb)
{
int psm_length, ps_info_length, es_map_length;
psm_length = get_be16(pb);
get_byte(pb);
get_byte(pb);
ps_info_length = get_be16(pb);
/* skip program_stream_info */
url_fskip(pb, ps_info_length);
es_map_length = get_be16(pb);
/* at least one es available? */
while (es_map_length >= 4){
unsigned char type = get_byte(pb);
unsigned char es_id = get_byte(pb);
uint16_t es_info_length = get_be16(pb);
/* remember mapping from stream id to stream type */
m->psm_es_type[es_id] = type;
/* skip program_stream_info */
url_fskip(pb, es_info_length);
es_map_length -= 4 + es_info_length;
}
get_be32(pb); /* crc32 */
return 2 + psm_length;
}
/* read the next PES header. Return its position in ppos
(if not NULL), and its start code, pts and dts.
*/
static int mpegps_read_pes_header(AVFormatContext *s,
int64_t *ppos, int *pstart_code,
int64_t *ppts, int64_t *pdts)
{
MpegDemuxContext *m = s->priv_data;
int len, size, startcode, c, flags, header_len;
int pes_ext, ext2_len, id_ext, skip;
int64_t pts, dts;
int64_t last_sync= url_ftell(s->pb);
error_redo:
url_fseek(s->pb, last_sync, SEEK_SET);
redo:
/* next start code (should be immediately after) */
m->header_state = 0xff;
size = MAX_SYNC_SIZE;
startcode = find_next_start_code(s->pb, &size, &m->header_state);
last_sync = url_ftell(s->pb);
//printf("startcode=%x pos=0x%"PRIx64"\n", startcode, url_ftell(s->pb));
if (startcode < 0)
return AVERROR(EIO);
if (startcode == PACK_START_CODE)
goto redo;
if (startcode == SYSTEM_HEADER_START_CODE)
goto redo;
if (startcode == PADDING_STREAM) {
url_fskip(s->pb, get_be16(s->pb));
goto redo;
}
if (startcode == PRIVATE_STREAM_2) {
len = get_be16(s->pb);
if (!m->sofdec) {
while (len-- >= 6) {
if (get_byte(s->pb) == 'S') {
uint8_t buf[5];
get_buffer(s->pb, buf, sizeof(buf));
m->sofdec = !memcmp(buf, "ofdec", 5);
len -= sizeof(buf);
break;
}
}
m->sofdec -= !m->sofdec;
}
url_fskip(s->pb, len);
goto redo;
}
if (startcode == PROGRAM_STREAM_MAP) {
mpegps_psm_parse(m, s->pb);
goto redo;
}
/* find matching stream */
if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||
(startcode >= 0x1e0 && startcode <= 0x1ef) ||
(startcode == 0x1bd) || (startcode == 0x1fd)))
goto redo;
if (ppos) {
*ppos = url_ftell(s->pb) - 4;
}
len = get_be16(s->pb);
pts =
dts = AV_NOPTS_VALUE;
/* stuffing */
for(;;) {
if (len < 1)
goto error_redo;
c = get_byte(s->pb);
len--;
/* XXX: for mpeg1, should test only bit 7 */
if (c != 0xff)
break;
}
if ((c & 0xc0) == 0x40) {
/* buffer scale & size */
get_byte(s->pb);
c = get_byte(s->pb);
len -= 2;
}
if ((c & 0xe0) == 0x20) {
dts = pts = get_pts(s->pb, c);
len -= 4;
if (c & 0x10){
dts = get_pts(s->pb, -1);
len -= 5;
}
} else if ((c & 0xc0) == 0x80) {
/* mpeg 2 PES */
#if 0 /* some streams have this field set for no apparent reason */
if ((c & 0x30) != 0) {
/* Encrypted multiplex not handled */
goto redo;
}
#endif
flags = get_byte(s->pb);
header_len = get_byte(s->pb);
len -= 2;
if (header_len > len)
goto error_redo;
len -= header_len;
if (flags & 0x80) {
dts = pts = get_pts(s->pb, -1);
header_len -= 5;
if (flags & 0x40) {
dts = get_pts(s->pb, -1);
header_len -= 5;
}
}
if (flags & 0x01) { /* PES extension */
pes_ext = get_byte(s->pb);
header_len--;
if (pes_ext & 0x40) { /* pack header - should be zero in PS */
goto error_redo;
}
/* Skip PES private data, program packet sequence counter and P-STD buffer */
skip = (pes_ext >> 4) & 0xb;
skip += skip & 0x9;
url_fskip(s->pb, skip);
header_len -= skip;
if (pes_ext & 0x01) { /* PES extension 2 */
ext2_len = get_byte(s->pb);
header_len--;
if ((ext2_len & 0x7f) > 0) {
id_ext = get_byte(s->pb);
if ((id_ext & 0x80) == 0)
startcode = ((startcode & 0xff) << 8) | id_ext;
header_len--;
}
}
}
if(header_len < 0)
goto error_redo;
url_fskip(s->pb, header_len);
}
else if( c!= 0xf )
goto redo;
if (startcode == PRIVATE_STREAM_1 && !m->psm_es_type[startcode & 0xff]) {
startcode = get_byte(s->pb);
len--;
if (startcode >= 0x80 && startcode <= 0xcf) {
/* audio: skip header */
get_byte(s->pb);
get_byte(s->pb);
get_byte(s->pb);
len -= 3;
if (startcode >= 0xb0 && startcode <= 0xbf) {
/* MLP/TrueHD audio has a 4-byte header */
get_byte(s->pb);
len--;
}
}
}
if(len<0)
goto error_redo;
if(dts != AV_NOPTS_VALUE && ppos){
int i;
for(i=0; i<s->nb_streams; i++){
if(startcode == s->streams[i]->id) {
ff_reduce_index(s, i);
av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);
}
}
}
*pstart_code = startcode;
*ppts = pts;
*pdts = dts;
return len;
}
static int mpegps_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
MpegDemuxContext *m = s->priv_data;
AVStream *st;
int len, startcode, i, type, codec_id = 0, es_type;
int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work
redo:
len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);
if (len < 0)
return len;
/* now find stream */
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
if (st->id == startcode)
goto found;
}
es_type = m->psm_es_type[startcode & 0xff];
if(es_type > 0){
if(es_type == STREAM_TYPE_VIDEO_MPEG1){
codec_id = CODEC_ID_MPEG2VIDEO;
type = CODEC_TYPE_VIDEO;
} else if(es_type == STREAM_TYPE_VIDEO_MPEG2){
codec_id = CODEC_ID_MPEG2VIDEO;
type = CODEC_TYPE_VIDEO;
} else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||
es_type == STREAM_TYPE_AUDIO_MPEG2){
codec_id = CODEC_ID_MP3;
type = CODEC_TYPE_AUDIO;
} else if(es_type == STREAM_TYPE_AUDIO_AAC){
codec_id = CODEC_ID_AAC;
type = CODEC_TYPE_AUDIO;
} else if(es_type == STREAM_TYPE_VIDEO_MPEG4){
codec_id = CODEC_ID_MPEG4;
type = CODEC_TYPE_VIDEO;
} else if(es_type == STREAM_TYPE_VIDEO_H264){
codec_id = CODEC_ID_H264;
type = CODEC_TYPE_VIDEO;
} else if(es_type == STREAM_TYPE_AUDIO_AC3){
codec_id = CODEC_ID_AC3;
type = CODEC_TYPE_AUDIO;
} else {
goto skip;
}
} else if (startcode >= 0x1e0 && startcode <= 0x1ef) {
static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };
unsigned char buf[8];
get_buffer(s->pb, buf, 8);
url_fseek(s->pb, -8, SEEK_CUR);
if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))
codec_id = CODEC_ID_CAVS;
else
codec_id = CODEC_ID_MPEG2VIDEO;
type = CODEC_TYPE_VIDEO;
} else if (startcode >= 0x1c0 && startcode <= 0x1df) {
type = CODEC_TYPE_AUDIO;
codec_id = m->sofdec > 0 ? CODEC_ID_ADPCM_ADX : CODEC_ID_MP2;
} else if (startcode >= 0x80 && startcode <= 0x87) {
type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_AC3;
} else if ((startcode >= 0x88 && startcode <= 0x8f)
||( startcode >= 0x98 && startcode <= 0x9f)) {
/* 0x90 - 0x97 is reserved for SDDS in DVD specs */
type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_DTS;
} else if (startcode >= 0xa0 && startcode <= 0xaf) {
type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_PCM_S16BE;
} else if (startcode >= 0xb0 && startcode <= 0xbf) {
type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_MLP;
} else if (startcode >= 0xc0 && startcode <= 0xcf) {
/* Used for both AC-3 and E-AC-3 in EVOB files */
type = CODEC_TYPE_AUDIO;
codec_id = CODEC_ID_AC3;
} else if (startcode >= 0x20 && startcode <= 0x3f) {
type = CODEC_TYPE_SUBTITLE;
codec_id = CODEC_ID_DVD_SUBTITLE;
} else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {
type = CODEC_TYPE_VIDEO;
codec_id = CODEC_ID_VC1;
} else {
skip:
/* skip packet */
url_fskip(s->pb, len);
goto redo;
}
/* no stream found: add a new stream */
st = av_new_stream(s, startcode);
if (!st)
goto skip;
st->codec->codec_type = type;
st->codec->codec_id = codec_id;
if (codec_id != CODEC_ID_PCM_S16BE)
st->need_parsing = AVSTREAM_PARSE_FULL;
found:
if(st->discard >= AVDISCARD_ALL)
goto skip;
if (startcode >= 0xa0 && startcode <= 0xaf) {
int b1, freq;
/* for LPCM, we just skip the header and consider it is raw
audio data */
if (len <= 3)
goto skip;
get_byte(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */
b1 = get_byte(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */
get_byte(s->pb); /* dynamic range control (0x80 = off) */
len -= 3;
freq = (b1 >> 4) & 3;
st->codec->sample_rate = lpcm_freq_tab[freq];
st->codec->channels = 1 + (b1 & 7);
st->codec->bit_rate = st->codec->channels * st->codec->sample_rate * 2;
}
av_new_packet(pkt, len);
get_buffer(s->pb, pkt->data, pkt->size);
pkt->pts = pts;
pkt->dts = dts;
pkt->stream_index = st->index;
#if 0
av_log(s, AV_LOG_DEBUG, "%d: pts=%0.3f dts=%0.3f size=%d\n",
pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0, pkt->size);
#endif
return 0;
}
static int mpegps_read_close(AVFormatContext *s)
{
return 0;
}
static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,
int64_t *ppos, int64_t pos_limit)
{
int len, startcode;
int64_t pos, pts, dts;
pos = *ppos;
#ifdef DEBUG_SEEK
printf("read_dts: pos=0x%"PRIx64" next=%d -> ", pos, find_next);
#endif
url_fseek(s->pb, pos, SEEK_SET);
for(;;) {
len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);
if (len < 0) {
#ifdef DEBUG_SEEK
printf("none (ret=%d)\n", len);
#endif
return AV_NOPTS_VALUE;
}
if (startcode == s->streams[stream_index]->id &&
dts != AV_NOPTS_VALUE) {
break;
}
url_fskip(s->pb, len);
}
#ifdef DEBUG_SEEK
printf("pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n", pos, dts, dts / 90000.0);
#endif
*ppos = pos;
return dts;
}
AVInputFormat mpegps_demuxer = {
"mpeg",
"MPEG PS format",
sizeof(MpegDemuxContext),
mpegps_probe,
mpegps_read_header,
mpegps_read_packet,
mpegps_read_close,
NULL, //mpegps_read_seek,
mpegps_read_dts,
.flags = AVFMT_SHOW_IDS,
};