FFmpeg: libavformat/flvenc.c Source File

00001 /*
00002  * FLV muxer
00003  * Copyright (c) 2003 The FFmpeg Project
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 #include "libavutil/intreadwrite.h"
00023 #include "libavutil/intfloat.h"
00024 #include "avformat.h"
00025 #include "flv.h"
00026 #include "internal.h"
00027 #include "avc.h"
00028 #include "metadata.h"
00029 #include "libavutil/dict.h"
00030 
00031 #undef NDEBUG
00032 #include <assert.h>
00033 
00034 static const AVCodecTag flv_video_codec_ids[] = {
00035     {CODEC_ID_FLV1,    FLV_CODECID_H263  },
00036     {CODEC_ID_H263,    FLV_CODECID_REALH263},
00037     {CODEC_ID_MPEG4,   FLV_CODECID_MPEG4 },
00038     {CODEC_ID_FLASHSV, FLV_CODECID_SCREEN},
00039     {CODEC_ID_FLASHSV2, FLV_CODECID_SCREEN2},
00040     {CODEC_ID_VP6F,    FLV_CODECID_VP6   },
00041     {CODEC_ID_VP6,     FLV_CODECID_VP6   },
00042     {CODEC_ID_VP6A,    FLV_CODECID_VP6A  },
00043     {CODEC_ID_H264,    FLV_CODECID_H264  },
00044     {CODEC_ID_NONE,    0}
00045 };
00046 
00047 static const AVCodecTag flv_audio_codec_ids[] = {
00048     {CODEC_ID_MP3,       FLV_CODECID_MP3    >> FLV_AUDIO_CODECID_OFFSET},
00049     {CODEC_ID_PCM_U8,    FLV_CODECID_PCM    >> FLV_AUDIO_CODECID_OFFSET},
00050     {CODEC_ID_PCM_S16BE, FLV_CODECID_PCM    >> FLV_AUDIO_CODECID_OFFSET},
00051     {CODEC_ID_PCM_S16LE, FLV_CODECID_PCM_LE >> FLV_AUDIO_CODECID_OFFSET},
00052     {CODEC_ID_ADPCM_SWF, FLV_CODECID_ADPCM  >> FLV_AUDIO_CODECID_OFFSET},
00053     {CODEC_ID_AAC,       FLV_CODECID_AAC    >> FLV_AUDIO_CODECID_OFFSET},
00054     {CODEC_ID_NELLYMOSER, FLV_CODECID_NELLYMOSER >> FLV_AUDIO_CODECID_OFFSET},
00055     {CODEC_ID_SPEEX,     FLV_CODECID_SPEEX  >> FLV_AUDIO_CODECID_OFFSET},
00056     {CODEC_ID_NONE,      0}
00057 };
00058 
00059 typedef struct FLVContext {
00060     int reserved;
00061     int64_t duration_offset;
00062     int64_t filesize_offset;
00063     int64_t duration;
00064     int64_t delay;      
00065 } FLVContext;
00066 
00067 typedef struct FLVStreamContext {
00068     int64_t last_ts;    
00069 } FLVStreamContext;
00070 
00071 static int get_audio_flags(AVFormatContext *s, AVCodecContext *enc)
00072 {
00073     int flags = (enc->bits_per_coded_sample == 16) ? FLV_SAMPLESSIZE_16BIT : FLV_SAMPLESSIZE_8BIT;
00074 
00075     if (enc->codec_id == CODEC_ID_AAC) // specs force these parameters
00076         return FLV_CODECID_AAC | FLV_SAMPLERATE_44100HZ | FLV_SAMPLESSIZE_16BIT | FLV_STEREO;
00077     else if (enc->codec_id == CODEC_ID_SPEEX) {
00078         if (enc->sample_rate != 16000) {
00079             av_log(s, AV_LOG_ERROR, "flv only supports wideband (16kHz) Speex audio\n");
00080             return -1;
00081         }
00082         if (enc->channels != 1) {
00083             av_log(s, AV_LOG_ERROR, "flv only supports mono Speex audio\n");
00084             return -1;
00085         }
00086         return FLV_CODECID_SPEEX | FLV_SAMPLERATE_11025HZ | FLV_SAMPLESSIZE_16BIT;
00087     } else {
00088     switch (enc->sample_rate) {
00089         case    44100:
00090             flags |= FLV_SAMPLERATE_44100HZ;
00091             break;
00092         case    22050:
00093             flags |= FLV_SAMPLERATE_22050HZ;
00094             break;
00095         case    11025:
00096             flags |= FLV_SAMPLERATE_11025HZ;
00097             break;
00098         case    16000: //nellymoser only
00099         case     8000: //nellymoser only
00100         case     5512: //not mp3
00101             if(enc->codec_id != CODEC_ID_MP3){
00102                 flags |= FLV_SAMPLERATE_SPECIAL;
00103                 break;
00104             }
00105         default:
00106             av_log(s, AV_LOG_ERROR, "flv does not support that sample rate, choose from (44100, 22050, 11025).\n");
00107             return -1;
00108     }
00109     }
00110 
00111     if (enc->channels > 1) {
00112         flags |= FLV_STEREO;
00113     }
00114 
00115     switch(enc->codec_id){
00116     case CODEC_ID_MP3:
00117         flags |= FLV_CODECID_MP3    | FLV_SAMPLESSIZE_16BIT;
00118         break;
00119     case CODEC_ID_PCM_U8:
00120         flags |= FLV_CODECID_PCM    | FLV_SAMPLESSIZE_8BIT;
00121         break;
00122     case CODEC_ID_PCM_S16BE:
00123         flags |= FLV_CODECID_PCM    | FLV_SAMPLESSIZE_16BIT;
00124         break;
00125     case CODEC_ID_PCM_S16LE:
00126         flags |= FLV_CODECID_PCM_LE | FLV_SAMPLESSIZE_16BIT;
00127         break;
00128     case CODEC_ID_ADPCM_SWF:
00129         flags |= FLV_CODECID_ADPCM | FLV_SAMPLESSIZE_16BIT;
00130         break;
00131     case CODEC_ID_NELLYMOSER:
00132         if (enc->sample_rate == 8000) {
00133             flags |= FLV_CODECID_NELLYMOSER_8KHZ_MONO | FLV_SAMPLESSIZE_16BIT;
00134         } else if (enc->sample_rate == 16000) {
00135             flags |= FLV_CODECID_NELLYMOSER_16KHZ_MONO | FLV_SAMPLESSIZE_16BIT;
00136         } else {
00137             flags |= FLV_CODECID_NELLYMOSER | FLV_SAMPLESSIZE_16BIT;
00138         }
00139         break;
00140     case 0:
00141         flags |= enc->codec_tag<<4;
00142         break;
00143     default:
00144         av_log(s, AV_LOG_ERROR, "codec not compatible with flv\n");
00145         return -1;
00146     }
00147 
00148     return flags;
00149 }
00150 
00151 static void put_amf_string(AVIOContext *pb, const char *str)
00152 {
00153     size_t len = strlen(str);
00154     avio_wb16(pb, len);
00155     avio_write(pb, str, len);
00156 }
00157 
00158 static void put_avc_eos_tag(AVIOContext *pb, unsigned ts) {
00159     avio_w8(pb, FLV_TAG_TYPE_VIDEO);
00160     avio_wb24(pb, 5);  /* Tag Data Size */
00161     avio_wb24(pb, ts);  /* lower 24 bits of timestamp in ms*/
00162     avio_w8(pb, (ts >> 24) & 0x7F);  /* MSB of ts in ms*/
00163     avio_wb24(pb, 0);  /* StreamId = 0 */
00164     avio_w8(pb, 23);  /* ub[4] FrameType = 1, ub[4] CodecId = 7 */
00165     avio_w8(pb, 2);  /* AVC end of sequence */
00166     avio_wb24(pb, 0);  /* Always 0 for AVC EOS. */
00167     avio_wb32(pb, 16);  /* Size of FLV tag */
00168 }
00169 
00170 static void put_amf_double(AVIOContext *pb, double d)
00171 {
00172     avio_w8(pb, AMF_DATA_TYPE_NUMBER);
00173     avio_wb64(pb, av_double2int(d));
00174 }
00175 
00176 static void put_amf_bool(AVIOContext *pb, int b) {
00177     avio_w8(pb, AMF_DATA_TYPE_BOOL);
00178     avio_w8(pb, !!b);
00179 }
00180 
00181 static int flv_write_header(AVFormatContext *s)
00182 {
00183     AVIOContext *pb = s->pb;
00184     FLVContext *flv = s->priv_data;
00185     AVCodecContext *audio_enc = NULL, *video_enc = NULL;
00186     int i, metadata_count = 0;
00187     double framerate = 0.0;
00188     int64_t metadata_size_pos, data_size, metadata_count_pos;
00189     AVDictionaryEntry *tag = NULL;
00190 
00191     for(i=0; i<s->nb_streams; i++){
00192         AVCodecContext *enc = s->streams[i]->codec;
00193         FLVStreamContext *sc;
00194         if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
00195             if (s->streams[i]->r_frame_rate.den && s->streams[i]->r_frame_rate.num) {
00196                 framerate = av_q2d(s->streams[i]->r_frame_rate);
00197             } else {
00198                 framerate = 1/av_q2d(s->streams[i]->codec->time_base);
00199             }
00200             video_enc = enc;
00201             if(enc->codec_tag == 0) {
00202                 av_log(s, AV_LOG_ERROR, "video codec not compatible with flv\n");
00203                 return -1;
00204             }
00205         } else if (enc->codec_type == AVMEDIA_TYPE_AUDIO) {
00206             audio_enc = enc;
00207             if (get_audio_flags(s, enc) < 0)
00208                 return -1;
00209         }
00210         avpriv_set_pts_info(s->streams[i], 32, 1, 1000); /* 32 bit pts in ms */
00211 
00212         sc = av_mallocz(sizeof(FLVStreamContext));
00213         if (!sc)
00214             return AVERROR(ENOMEM);
00215         s->streams[i]->priv_data = sc;
00216         sc->last_ts = -1;
00217     }
00218     flv->delay = AV_NOPTS_VALUE;
00219 
00220     avio_write(pb, "FLV", 3);
00221     avio_w8(pb,1);
00222     avio_w8(pb,   FLV_HEADER_FLAG_HASAUDIO * !!audio_enc
00223                  + FLV_HEADER_FLAG_HASVIDEO * !!video_enc);
00224     avio_wb32(pb,9);
00225     avio_wb32(pb,0);
00226 
00227     for(i=0; i<s->nb_streams; i++){
00228         if(s->streams[i]->codec->codec_tag == 5){
00229             avio_w8(pb,8); // message type
00230             avio_wb24(pb,0); // include flags
00231             avio_wb24(pb,0); // time stamp
00232             avio_wb32(pb,0); // reserved
00233             avio_wb32(pb,11); // size
00234             flv->reserved=5;
00235         }
00236     }
00237 
00238     /* write meta_tag */
00239     avio_w8(pb, 18);         // tag type META
00240     metadata_size_pos= avio_tell(pb);
00241     avio_wb24(pb, 0);          // size of data part (sum of all parts below)
00242     avio_wb24(pb, 0);          // time stamp
00243     avio_wb32(pb, 0);          // reserved
00244 
00245     /* now data of data_size size */
00246 
00247     /* first event name as a string */
00248     avio_w8(pb, AMF_DATA_TYPE_STRING);
00249     put_amf_string(pb, "onMetaData"); // 12 bytes
00250 
00251     /* mixed array (hash) with size and string/type/data tuples */
00252     avio_w8(pb, AMF_DATA_TYPE_MIXEDARRAY);
00253     metadata_count_pos = avio_tell(pb);
00254     metadata_count = 5*!!video_enc + 5*!!audio_enc + 2; // +2 for duration and file size
00255     avio_wb32(pb, metadata_count);
00256 
00257     put_amf_string(pb, "duration");
00258     flv->duration_offset= avio_tell(pb);
00259     put_amf_double(pb, s->duration / AV_TIME_BASE); // fill in the guessed duration, it'll be corrected later if incorrect
00260 
00261     if(video_enc){
00262         put_amf_string(pb, "width");
00263         put_amf_double(pb, video_enc->width);
00264 
00265         put_amf_string(pb, "height");
00266         put_amf_double(pb, video_enc->height);
00267 
00268         put_amf_string(pb, "videodatarate");
00269         put_amf_double(pb, video_enc->bit_rate / 1024.0);
00270 
00271         put_amf_string(pb, "framerate");
00272         put_amf_double(pb, framerate);
00273 
00274         put_amf_string(pb, "videocodecid");
00275         put_amf_double(pb, video_enc->codec_tag);
00276     }
00277 
00278     if(audio_enc){
00279         put_amf_string(pb, "audiodatarate");
00280         put_amf_double(pb, audio_enc->bit_rate / 1024.0);
00281 
00282         put_amf_string(pb, "audiosamplerate");
00283         put_amf_double(pb, audio_enc->sample_rate);
00284 
00285         put_amf_string(pb, "audiosamplesize");
00286         put_amf_double(pb, audio_enc->codec_id == CODEC_ID_PCM_U8 ? 8 : 16);
00287 
00288         put_amf_string(pb, "stereo");
00289         put_amf_bool(pb, audio_enc->channels == 2);
00290 
00291         put_amf_string(pb, "audiocodecid");
00292         put_amf_double(pb, audio_enc->codec_tag);
00293     }
00294 
00295     while ((tag = av_dict_get(s->metadata, "", tag, AV_DICT_IGNORE_SUFFIX))) {
00296         if(   !strcmp(tag->key, "width")
00297             ||!strcmp(tag->key, "height")
00298             ||!strcmp(tag->key, "videodatarate")
00299             ||!strcmp(tag->key, "framerate")
00300             ||!strcmp(tag->key, "videocodecid")
00301             ||!strcmp(tag->key, "audiodatarate")
00302             ||!strcmp(tag->key, "audiosamplerate")
00303             ||!strcmp(tag->key, "audiosamplesize")
00304             ||!strcmp(tag->key, "stereo")
00305             ||!strcmp(tag->key, "audiocodecid")
00306             ||!strcmp(tag->key, "duration")
00307             ||!strcmp(tag->key, "onMetaData")
00308         ){
00309             av_log(s, AV_LOG_DEBUG, "ignoring metadata for %s\n", tag->key);
00310             continue;
00311         }
00312         put_amf_string(pb, tag->key);
00313         avio_w8(pb, AMF_DATA_TYPE_STRING);
00314         put_amf_string(pb, tag->value);
00315         metadata_count++;
00316     }
00317 
00318     put_amf_string(pb, "filesize");
00319     flv->filesize_offset= avio_tell(pb);
00320     put_amf_double(pb, 0); // delayed write
00321 
00322     put_amf_string(pb, "");
00323     avio_w8(pb, AMF_END_OF_OBJECT);
00324 
00325     /* write total size of tag */
00326     data_size= avio_tell(pb) - metadata_size_pos - 10;
00327 
00328     avio_seek(pb, metadata_count_pos, SEEK_SET);
00329     avio_wb32(pb, metadata_count);
00330 
00331     avio_seek(pb, metadata_size_pos, SEEK_SET);
00332     avio_wb24(pb, data_size);
00333     avio_skip(pb, data_size + 10 - 3);
00334     avio_wb32(pb, data_size + 11);
00335 
00336     for (i = 0; i < s->nb_streams; i++) {
00337         AVCodecContext *enc = s->streams[i]->codec;
00338         if (enc->codec_id == CODEC_ID_AAC || enc->codec_id == CODEC_ID_H264 || enc->codec_id == CODEC_ID_MPEG4) {
00339             int64_t pos;
00340             avio_w8(pb, enc->codec_type == AVMEDIA_TYPE_VIDEO ?
00341                      FLV_TAG_TYPE_VIDEO : FLV_TAG_TYPE_AUDIO);
00342             avio_wb24(pb, 0); // size patched later
00343             avio_wb24(pb, 0); // ts
00344             avio_w8(pb, 0); // ts ext
00345             avio_wb24(pb, 0); // streamid
00346             pos = avio_tell(pb);
00347             if (enc->codec_id == CODEC_ID_AAC) {
00348                 avio_w8(pb, get_audio_flags(s, enc));
00349                 avio_w8(pb, 0); // AAC sequence header
00350                 avio_write(pb, enc->extradata, enc->extradata_size);
00351             } else {
00352                 avio_w8(pb, enc->codec_tag | FLV_FRAME_KEY); // flags
00353                 avio_w8(pb, 0); // AVC sequence header
00354                 avio_wb24(pb, 0); // composition time
00355                 ff_isom_write_avcc(pb, enc->extradata, enc->extradata_size);
00356             }
00357             data_size = avio_tell(pb) - pos;
00358             avio_seek(pb, -data_size - 10, SEEK_CUR);
00359             avio_wb24(pb, data_size);
00360             avio_skip(pb, data_size + 10 - 3);
00361             avio_wb32(pb, data_size + 11); // previous tag size
00362         }
00363     }
00364 
00365     return 0;
00366 }
00367 
00368 static int flv_write_trailer(AVFormatContext *s)
00369 {
00370     int64_t file_size;
00371 
00372     AVIOContext *pb = s->pb;
00373     FLVContext *flv = s->priv_data;
00374     int i;
00375 
00376     /* Add EOS tag */
00377     for (i = 0; i < s->nb_streams; i++) {
00378         AVCodecContext *enc = s->streams[i]->codec;
00379         FLVStreamContext *sc = s->streams[i]->priv_data;
00380         if (enc->codec_type == AVMEDIA_TYPE_VIDEO &&
00381                 (enc->codec_id == CODEC_ID_H264 || enc->codec_id == CODEC_ID_MPEG4)) {
00382             put_avc_eos_tag(pb, sc->last_ts);
00383         }
00384     }
00385 
00386     file_size = avio_tell(pb);
00387 
00388     /* update information */
00389     avio_seek(pb, flv->duration_offset, SEEK_SET);
00390     put_amf_double(pb, flv->duration / (double)1000);
00391     avio_seek(pb, flv->filesize_offset, SEEK_SET);
00392     put_amf_double(pb, file_size);
00393 
00394     avio_seek(pb, file_size, SEEK_SET);
00395     return 0;
00396 }
00397 
00398 static int flv_write_packet(AVFormatContext *s, AVPacket *pkt)
00399 {
00400     AVIOContext *pb = s->pb;
00401     AVCodecContext *enc = s->streams[pkt->stream_index]->codec;
00402     FLVContext *flv = s->priv_data;
00403     FLVStreamContext *sc = s->streams[pkt->stream_index]->priv_data;
00404     unsigned ts;
00405     int size= pkt->size;
00406     uint8_t *data= NULL;
00407     int flags, flags_size;
00408 
00409 //    av_log(s, AV_LOG_DEBUG, "type:%d pts: %"PRId64" size:%d\n", enc->codec_type, timestamp, size);
00410 
00411     if(enc->codec_id == CODEC_ID_VP6 || enc->codec_id == CODEC_ID_VP6F ||
00412        enc->codec_id == CODEC_ID_VP6A || enc->codec_id == CODEC_ID_AAC)
00413         flags_size= 2;
00414     else if(enc->codec_id == CODEC_ID_H264 || enc->codec_id == CODEC_ID_MPEG4)
00415         flags_size= 5;
00416     else
00417         flags_size= 1;
00418 
00419     if (enc->codec_type == AVMEDIA_TYPE_VIDEO) {
00420         avio_w8(pb, FLV_TAG_TYPE_VIDEO);
00421 
00422         flags = enc->codec_tag;
00423         if(flags == 0) {
00424             av_log(s, AV_LOG_ERROR, "video codec %s not compatible with flv\n", avcodec_get_name(enc->codec_id));
00425             return -1;
00426         }
00427 
00428         flags |= pkt->flags & AV_PKT_FLAG_KEY ? FLV_FRAME_KEY : FLV_FRAME_INTER;
00429     } else if (enc->codec_type == AVMEDIA_TYPE_AUDIO) {
00430         flags = get_audio_flags(s, enc);
00431 
00432         assert(size);
00433 
00434         avio_w8(pb, FLV_TAG_TYPE_AUDIO);
00435     } else {
00436         // In-band flv metadata ("scriptdata")
00437         assert(enc->codec_type == AVMEDIA_TYPE_DATA);
00438         avio_w8(pb, FLV_TAG_TYPE_META);
00439         flags_size = 0;
00440         flags = 0;
00441     }
00442 
00443     if (enc->codec_id == CODEC_ID_H264 || enc->codec_id == CODEC_ID_MPEG4) {
00444         /* check if extradata looks like mp4 formated */
00445         if (enc->extradata_size > 0 && *(uint8_t*)enc->extradata != 1) {
00446             if (ff_avc_parse_nal_units_buf(pkt->data, &data, &size) < 0)
00447                 return -1;
00448         }
00449     } else if (enc->codec_id == CODEC_ID_AAC && pkt->size > 2 &&
00450                (AV_RB16(pkt->data) & 0xfff0) == 0xfff0) {
00451         av_log(s, AV_LOG_ERROR, "malformated aac bitstream, use -absf aac_adtstoasc\n");
00452         return -1;
00453     }
00454     if (flv->delay == AV_NOPTS_VALUE)
00455         flv->delay = -pkt->dts;
00456     if (pkt->dts < -flv->delay) {
00457         av_log(s, AV_LOG_WARNING, "Packets are not in the proper order with "
00458                                   "respect to DTS\n");
00459         return AVERROR(EINVAL);
00460     }
00461 
00462     ts = pkt->dts + flv->delay; // add delay to force positive dts
00463 
00464     /* check Speex packet duration */
00465     if (enc->codec_id == CODEC_ID_SPEEX && ts - sc->last_ts > 160) {
00466         av_log(s, AV_LOG_WARNING, "Warning: Speex stream has more than "
00467                                   "8 frames per packet. Adobe Flash "
00468                                   "Player cannot handle this!\n");
00469     }
00470 
00471     if (sc->last_ts < ts)
00472         sc->last_ts = ts;
00473 
00474     avio_wb24(pb,size + flags_size);
00475     avio_wb24(pb,ts);
00476     avio_w8(pb,(ts >> 24) & 0x7F); // timestamps are 32bits _signed_
00477     avio_wb24(pb,flv->reserved);
00478 
00479     if(flags_size)
00480         avio_w8(pb,flags);
00481 
00482     if (enc->codec_id == CODEC_ID_VP6)
00483         avio_w8(pb,0);
00484     if (enc->codec_id == CODEC_ID_VP6F || enc->codec_id == CODEC_ID_VP6A)
00485         avio_w8(pb, enc->extradata_size ? enc->extradata[0] : 0);
00486     else if (enc->codec_id == CODEC_ID_AAC)
00487         avio_w8(pb,1); // AAC raw
00488     else if (enc->codec_id == CODEC_ID_H264 || enc->codec_id == CODEC_ID_MPEG4) {
00489         avio_w8(pb,1); // AVC NALU
00490         avio_wb24(pb,pkt->pts - pkt->dts);
00491     }
00492 
00493     avio_write(pb, data ? data : pkt->data, size);
00494 
00495     avio_wb32(pb,size+flags_size+11); // previous tag size
00496     flv->duration = FFMAX(flv->duration, pkt->pts + flv->delay + pkt->duration);
00497 
00498     avio_flush(pb);
00499 
00500     av_free(data);
00501 
00502     return pb->error;
00503 }
00504 
00505 AVOutputFormat ff_flv_muxer = {
00506     .name           = "flv",
00507     .long_name      = NULL_IF_CONFIG_SMALL("FLV format"),
00508     .mime_type      = "video/x-flv",
00509     .extensions     = "flv",
00510     .priv_data_size = sizeof(FLVContext),
00511 #if CONFIG_LIBMP3LAME
00512     .audio_codec    = CODEC_ID_MP3,
00513 #else // CONFIG_LIBMP3LAME
00514     .audio_codec    = CODEC_ID_ADPCM_SWF,
00515 #endif // CONFIG_LIBMP3LAME
00516     .video_codec    = CODEC_ID_FLV1,
00517     .write_header   = flv_write_header,
00518     .write_packet   = flv_write_packet,
00519     .write_trailer  = flv_write_trailer,
00520     .codec_tag      = (const AVCodecTag* const []){
00521         flv_video_codec_ids, flv_audio_codec_ids, 0
00522     },
00523     .flags          = AVFMT_GLOBALHEADER | AVFMT_VARIABLE_FPS |
00524                       AVFMT_TS_NONSTRICT,
00525 };