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ffmpeg / libavformat / flvenc.c @ 37cdf93d

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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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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 */
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#include "avformat.h"
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#undef NDEBUG
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#include <assert.h>
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typedef struct FLVContext {
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    int hasAudio;
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    int hasVideo;
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    int reserved;
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} FLVContext;
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static void put_be24(ByteIOContext *pb, int value)
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{
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    put_byte(pb, (value>>16) & 0xFF );
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    put_byte(pb, (value>> 8) & 0xFF );
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    put_byte(pb, (value>> 0) & 0xFF );
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}
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static int get_audio_flags(AVCodecContext *enc){
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    int flags = 0x02;
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    switch (enc->sample_rate) {
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        case    44100:
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            flags |= 0x0C;
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            break;
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        case    22050:
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            flags |= 0x08;
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            break;
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        case    11025:
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            flags |= 0x04;
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            break;
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        case     8000: //nellymoser only
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        case     5512: //not mp3
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            flags |= 0x00;
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            break;
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        default:
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            return -1;
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    }
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    if (enc->channels > 1) {
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        flags |= 0x01;
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    }
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    switch(enc->codec_id){
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    case CODEC_ID_MP3:
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        flags |= 0x20;
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        break;
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    case 0:
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        flags |= enc->codec_tag<<4;
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        break;
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    default:
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        return -1;
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    }
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    return flags;
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}
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static int flv_write_header(AVFormatContext *s)
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{
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    ByteIOContext *pb = &s->pb;
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    FLVContext *flv = s->priv_data;
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    int i;
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    flv->hasAudio = 0;
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    flv->hasVideo = 0;
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    put_tag(pb,"FLV");
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    put_byte(pb,1);
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    put_byte(pb,0); // delayed write
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    put_be32(pb,9);
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    put_be32(pb,0);
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    for(i=0; i<s->nb_streams; i++){
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        AVCodecContext *enc = &s->streams[i]->codec;
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        av_set_pts_info(s->streams[i], 24, 1, 1000); /* 24 bit pts in ms */
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        if(enc->codec_tag == 5){
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            put_byte(pb,8); // message type
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            put_be24(pb,0); // include flags
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            put_be24(pb,0); // time stamp
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            put_be32(pb,0); // reserved
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            put_be32(pb,11); // size
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            flv->reserved=5;
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        }
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        if(enc->codec_type == CODEC_TYPE_AUDIO && get_audio_flags(enc)<0)
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            return -1;
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    }
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    return 0;
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}
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static int flv_write_trailer(AVFormatContext *s)
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{
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    int64_t file_size;
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    int flags = 0;
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    ByteIOContext *pb = &s->pb;
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    FLVContext *flv = s->priv_data;
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    file_size = url_ftell(pb);
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    flags |= flv->hasAudio ? 4 : 0;
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    flags |= flv->hasVideo ? 1 : 0;
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    url_fseek(pb, 4, SEEK_SET);
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    put_byte(pb,flags);
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    url_fseek(pb, file_size, SEEK_SET);
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    return 0;
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}
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static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    ByteIOContext *pb = &s->pb;
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    AVCodecContext *enc = &s->streams[pkt->stream_index]->codec;
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    FLVContext *flv = s->priv_data;
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    int size= pkt->size;
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    int flags;
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//    av_log(s, AV_LOG_DEBUG, "type:%d pts: %lld size:%d\n", enc->codec_type, timestamp, size);
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    if (enc->codec_type == CODEC_TYPE_VIDEO) {
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        put_byte(pb, 9);
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        flags = 2; // choose h263
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        flags |= pkt->flags & PKT_FLAG_KEY ? 0x10 : 0x20; // add keyframe indicator
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        flv->hasVideo = 1;
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    } else {
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        assert(enc->codec_type == CODEC_TYPE_AUDIO);
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        flags = get_audio_flags(enc);
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        assert(size);
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        put_byte(pb, 8);
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        // We got audio! Make sure we set this to the global flags on closure
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        flv->hasAudio = 1;
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    }
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    put_be24(pb,size+1); // include flags
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    put_be24(pb,pkt->pts);
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    put_be32(pb,flv->reserved);
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    put_byte(pb,flags);
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    put_buffer(pb, pkt->data, size);
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    put_be32(pb,size+1+11); // reserved
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    put_flush_packet(pb);
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    return 0;
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}
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static AVOutputFormat flv_oformat = {
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    "flv",
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    "flv format",
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    "video/x-flashvideo",
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    "flv",
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    sizeof(FLVContext),
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#ifdef CONFIG_MP3LAME
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    CODEC_ID_MP3,
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#else // CONFIG_MP3LAME
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    CODEC_ID_NONE,
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#endif // CONFIG_MP3LAME
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    CODEC_ID_FLV1,
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    flv_write_header,
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    flv_write_packet,
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    flv_write_trailer,
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};
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int flvenc_init(void)
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{
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    av_register_output_format(&flv_oformat);
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    return 0;
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}