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ffmpeg/libavformat/flvdec.c

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/*
* FLV demuxer
* Copyright (c) 2003 The FFmpeg Project.
*
* 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
*
*
* This demuxer will generate a 1 byte extradata for VP6F content.
* It is composed of:
* - upper 4bits: difference between encoded width and visible width
* - lower 4bits: difference between encoded height and visible height
*/
#include "avformat.h"
static int flv_probe(AVProbeData *p)
{
const uint8_t *d;
if (p->buf_size < 6)
return 0;
d = p->buf;
if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V') {
return 50;
}
return 0;
}
static int flv_read_header(AVFormatContext *s,
AVFormatParameters *ap)
{
int offset, flags, size;
s->ctx_flags |= AVFMTCTX_NOHEADER; //ok we have a header but theres no fps, codec type, sample_rate, ...
url_fskip(&s->pb, 4);
flags = get_byte(&s->pb);
offset = get_be32(&s->pb);
if(!url_is_streamed(&s->pb)){
const int fsize= url_fsize(&s->pb);
url_fseek(&s->pb, fsize-4, SEEK_SET);
size= get_be32(&s->pb);
url_fseek(&s->pb, fsize-3-size, SEEK_SET);
if(size == get_be24(&s->pb) + 11){
s->duration= get_be24(&s->pb) * (int64_t)AV_TIME_BASE / 1000;
}
}
url_fseek(&s->pb, offset, SEEK_SET);
s->start_time = 0;
return 0;
}
static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
{
int ret, i, type, size, pts, flags, is_audio, next, pos;
AVStream *st = NULL;
for(;;){
pos = url_ftell(&s->pb);
url_fskip(&s->pb, 4); /* size of previous packet */
type = get_byte(&s->pb);
size = get_be24(&s->pb);
pts = get_be24(&s->pb);
// av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, pts:%d\n", type, size, pts);
if (url_feof(&s->pb))
return AVERROR_IO;
url_fskip(&s->pb, 4); /* reserved */
flags = 0;
if(size == 0)
continue;
next= size + url_ftell(&s->pb);
if (type == 8) {
is_audio=1;
flags = get_byte(&s->pb);
} else if (type == 9) {
is_audio=0;
flags = get_byte(&s->pb);
} else if (type == 18 && size > 13+1+4) {
url_fskip(&s->pb, 13); //onMetaData blah
if(get_byte(&s->pb) == 8){
url_fskip(&s->pb, 4);
}
while(url_ftell(&s->pb) + 5 < next){
char tmp[128];
int type, len;
double d= 0;
len= get_be16(&s->pb);
if(len >= sizeof(tmp) || !len)
break;
get_buffer(&s->pb, tmp, len);
tmp[len]=0;
type= get_byte(&s->pb);
if(type==0){
d= av_int2dbl(get_be64(&s->pb));
}else if(type==2){
len= get_be16(&s->pb);
if(len >= sizeof(tmp))
break;
url_fskip(&s->pb, len);
}else if(type==8){
//array
break;
}else if(type==11){
d= av_int2dbl(get_be64(&s->pb));
get_be16(&s->pb);
}
if(!strcmp(tmp, "duration")){
s->duration = d*AV_TIME_BASE;
}else if(!strcmp(tmp, "videodatarate")){
}else if(!strcmp(tmp, "audiodatarate")){
}
}
url_fseek(&s->pb, next, SEEK_SET);
continue;
} else {
/* skip packet */
av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
url_fseek(&s->pb, next, SEEK_SET);
continue;
}
/* now find stream */
for(i=0;i<s->nb_streams;i++) {
st = s->streams[i];
if (st->id == is_audio)
break;
}
if(i == s->nb_streams){
st = av_new_stream(s, is_audio);
if (!st)
return AVERROR_NOMEM;
av_set_pts_info(st, 24, 1, 1000); /* 24 bit pts in ms */
st->codec->time_base= (AVRational){1,1000};
}
// av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
if( (st->discard >= AVDISCARD_NONKEY && !((flags >> 4)==1 || is_audio))
||(st->discard >= AVDISCARD_BIDIR && ((flags >> 4)==3 && !is_audio))
|| st->discard >= AVDISCARD_ALL
){
url_fseek(&s->pb, next, SEEK_SET);
continue;
}
if ((flags >> 4)==1)
av_add_index_entry(st, pos, pts, size, 0, AVINDEX_KEYFRAME);
break;
}
if(is_audio){
if(st->codec->sample_rate == 0){
st->codec->codec_type = CODEC_TYPE_AUDIO;
st->codec->channels = (flags&1)+1;
if((flags >> 4) == 5)
st->codec->sample_rate= 8000;
else
st->codec->sample_rate = (44100<<((flags>>2)&3))>>3;
switch(flags >> 4){/* 0: uncompressed 1: ADPCM 2: mp3 5: Nellymoser 8kHz mono 6: Nellymoser*/
case 0: if (flags&2) st->codec->codec_id = CODEC_ID_PCM_S16BE;
else st->codec->codec_id = CODEC_ID_PCM_S8; break;
case 1: st->codec->codec_id = CODEC_ID_ADPCM_SWF; break;
case 2: st->codec->codec_id = CODEC_ID_MP3; st->need_parsing = 1; break;
// this is not listed at FLV but at SWF, strange...
case 3: if (flags&2) st->codec->codec_id = CODEC_ID_PCM_S16LE;
else st->codec->codec_id = CODEC_ID_PCM_S8; break;
default:
av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flags >> 4);
st->codec->codec_tag= (flags >> 4);
}
st->codec->bits_per_sample = (flags & 2) ? 16 : 8;
}
}else{
st->codec->codec_type = CODEC_TYPE_VIDEO;
switch(flags & 0xF){
case 2: st->codec->codec_id = CODEC_ID_FLV1; break;
case 3: st->codec->codec_id = CODEC_ID_FLASHSV; break;
case 4:
st->codec->codec_id = CODEC_ID_VP6F;
if (st->codec->extradata_size != 1) {
st->codec->extradata_size = 1;
st->codec->extradata = av_malloc(1);
}
/* width and height adjustment */
st->codec->extradata[0] = get_byte(&s->pb);
size--;
break;
default:
av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flags & 0xf);
st->codec->codec_tag= flags & 0xF;
}
}
ret= av_get_packet(&s->pb, pkt, size - 1);
if (ret <= 0) {
return AVERROR_IO;
}
/* note: we need to modify the packet size here to handle the last
packet */
pkt->size = ret;
pkt->pts = pts;
pkt->stream_index = st->index;
if (is_audio || ((flags >> 4)==1))
pkt->flags |= PKT_FLAG_KEY;
return ret;
}
static int flv_read_close(AVFormatContext *s)
{
return 0;
}
static int flv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
{
AVStream *st = s->streams[stream_index];
int index = av_index_search_timestamp(st, timestamp, flags);
if (index < 0)
return -1;
url_fseek(&s->pb, st->index_entries[index].pos, SEEK_SET);
return 0;
}
AVInputFormat flv_demuxer = {
"flv",
"flv format",
0,
flv_probe,
flv_read_header,
flv_read_packet,
flv_read_close,
flv_read_seek,
.extensions = "flv",
.value = CODEC_ID_FLV1,
};
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