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ffmpeg / libavformat / flvdec.c @ 5ce117c3

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/*
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 * FLV encoder.
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 * Copyright (c) 2003 The FFmpeg Project.
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 *
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 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2 of the License, or (at your option) any later version.
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 *
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 * This library is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "avformat.h"
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static int flv_probe(AVProbeData *p)
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{
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    const uint8_t *d;
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    if (p->buf_size < 6)
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        return 0;
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    d = p->buf;
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    if (d[0] == 'F' && d[1] == 'L' && d[2] == 'V') {
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        return 50;
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    }
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    return 0;
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}
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static int flv_read_header(AVFormatContext *s,
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                           AVFormatParameters *ap)
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{
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    int offset, flags, size;
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    s->ctx_flags |= AVFMTCTX_NOHEADER; //ok we have a header but theres no fps, codec type, sample_rate, ...
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    url_fskip(&s->pb, 4);
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    flags = get_byte(&s->pb);
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    offset = get_be32(&s->pb);
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    if(!url_is_streamed(&s->pb)){
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        const int fsize= url_fsize(&s->pb);
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        url_fseek(&s->pb, fsize-4, SEEK_SET);
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        size= get_be32(&s->pb);
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        url_fseek(&s->pb, fsize-3-size, SEEK_SET);
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        if(size == get_be24(&s->pb) + 11){
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            s->duration= get_be24(&s->pb) * (int64_t)AV_TIME_BASE / 1000;
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        }
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    }
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    url_fseek(&s->pb, offset, SEEK_SET);
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    return 0;
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}
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static int flv_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    int ret, i, type, size, pts, flags, is_audio, next;
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    AVStream *st = NULL;
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 for(;;){
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    url_fskip(&s->pb, 4); /* size of previous packet */
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    type = get_byte(&s->pb);
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    size = get_be24(&s->pb);
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    pts = get_be24(&s->pb);
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//    av_log(s, AV_LOG_DEBUG, "type:%d, size:%d, pts:%d\n", type, size, pts);
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    if (url_feof(&s->pb))
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        return AVERROR_IO;
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    url_fskip(&s->pb, 4); /* reserved */
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    flags = 0;
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    if(size == 0)
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        continue;
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    next= size + url_ftell(&s->pb);
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    if (type == 8) {
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        is_audio=1;
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        flags = get_byte(&s->pb);
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    } else if (type == 9) {
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        is_audio=0;
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        flags = get_byte(&s->pb);
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    } else if (type == 18 && size > 13+1+4) {
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        url_fskip(&s->pb, 13); //onMetaData blah
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        if(get_byte(&s->pb) == 8){
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            url_fskip(&s->pb, 4);
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        }
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        while(url_ftell(&s->pb) + 5 < next){
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            char tmp[128];
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            int type, len;
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            double d= 0;
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            len= get_be16(&s->pb);
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            if(len >= sizeof(tmp) || !len)
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                break;
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            get_buffer(&s->pb, tmp, len);
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            tmp[len]=0;
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            type= get_byte(&s->pb);
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            if(type==0){
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                d= av_int2dbl(get_be64(&s->pb));
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            }else if(type==2){
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                len= get_be16(&s->pb);
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                if(len >= sizeof(tmp))
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                    break;
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                url_fskip(&s->pb, len);
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            }else if(type==8){
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                //array
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                break;
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            }else if(type==11){
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                d= av_int2dbl(get_be64(&s->pb));
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                get_be16(&s->pb);
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            }
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            if(!strcmp(tmp, "duration")){
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                s->duration = d*AV_TIME_BASE;
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            }else if(!strcmp(tmp, "videodatarate")){
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            }else if(!strcmp(tmp, "audiodatarate")){
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            }
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        }
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        url_fseek(&s->pb, next, SEEK_SET);
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        continue;
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    } else {
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        /* skip packet */
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        av_log(s, AV_LOG_ERROR, "skipping flv packet: type %d, size %d, flags %d\n", type, size, flags);
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        url_fseek(&s->pb, next, SEEK_SET);
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        continue;
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    }
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    /* now find stream */
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    for(i=0;i<s->nb_streams;i++) {
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        st = s->streams[i];
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        if (st->id == is_audio)
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            break;
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    }
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    if(i == s->nb_streams){
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        st = av_new_stream(s, is_audio);
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        if (!st)
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            return AVERROR_NOMEM;
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        av_set_pts_info(st, 24, 1, 1000); /* 24 bit pts in ms */
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        st->codec->time_base= (AVRational){1,1000};
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    }
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//    av_log(NULL, AV_LOG_DEBUG, "%d %X %d \n", is_audio, flags, st->discard);
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    if(  (st->discard >= AVDISCARD_NONKEY && !((flags >> 4)==1 ||  is_audio))
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       ||(st->discard >= AVDISCARD_BIDIR  &&  ((flags >> 4)==3 && !is_audio))
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       || st->discard >= AVDISCARD_ALL
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       ){
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        url_fseek(&s->pb, next, SEEK_SET);
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        continue;
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    }
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    break;
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 }
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    if(is_audio){
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        if(st->codec->sample_rate == 0){
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            st->codec->codec_type = CODEC_TYPE_AUDIO;
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            st->codec->channels = (flags&1)+1;
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            if((flags >> 4) == 5)
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                st->codec->sample_rate= 8000;
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            else
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                st->codec->sample_rate = (44100<<((flags>>2)&3))>>3;
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            switch(flags >> 4){/* 0: uncompressed 1: ADPCM 2: mp3 5: Nellymoser 8kHz mono 6: Nellymoser*/
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            case 0: if (flags&2) st->codec->codec_id = CODEC_ID_PCM_S16BE;
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                    else st->codec->codec_id = CODEC_ID_PCM_S8; break;
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            case 1: st->codec->codec_id = CODEC_ID_ADPCM_SWF; break;
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            case 2: st->codec->codec_id = CODEC_ID_MP3; break;
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            // this is not listed at FLV but at SWF, strange...
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            case 3: if (flags&2) st->codec->codec_id = CODEC_ID_PCM_S16LE;
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                    else st->codec->codec_id = CODEC_ID_PCM_S8; break;
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            default:
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                    av_log(s, AV_LOG_INFO, "Unsupported audio codec (%x)\n", flags >> 4);
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                st->codec->codec_tag= (flags >> 4);
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            }
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            st->codec->bits_per_sample = (flags & 2) ? 16 : 8;
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        }
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    }else{
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            st->codec->codec_type = CODEC_TYPE_VIDEO;
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            switch(flags & 0xF){
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            case 2: st->codec->codec_id = CODEC_ID_FLV1; break;
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            case 3: st->codec->codec_id = CODEC_ID_FLASHSV; break;
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            case 4:
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                st->codec->codec_id = CODEC_ID_VP6F;
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                get_byte(&s->pb); /* width and height adjustment */
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                size--;
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                break;
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            default:
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                    av_log(s, AV_LOG_INFO, "Unsupported video codec (%x)\n", flags & 0xf);
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                st->codec->codec_tag= flags & 0xF;
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            }
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    }
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    ret= av_get_packet(&s->pb, pkt, size - 1);
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    if (ret <= 0) {
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        return AVERROR_IO;
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    }
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    /* note: we need to modify the packet size here to handle the last
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       packet */
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    pkt->size = ret;
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    pkt->pts = pts;
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    pkt->stream_index = st->index;
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    if (is_audio || ((flags >> 4)==1))
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        pkt->flags |= PKT_FLAG_KEY;
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    return ret;
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}
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static int flv_read_close(AVFormatContext *s)
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{
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    return 0;
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}
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AVInputFormat flv_demuxer = {
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    "flv",
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    "flv format",
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    0,
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    flv_probe,
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    flv_read_header,
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    flv_read_packet,
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    flv_read_close,
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    .extensions = "flv",
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    .value = CODEC_ID_FLV1,
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};