[FFmpeg-trac] #2658(avformat:new): Written mp4 with h264/AAC unplayable (discrepancy with libav)

[FFmpeg]

#2658: Written mp4 with h264/AAC unplayable (discrepancy with libav)
----------------------------------+----------------------------------
             Reporter:  Lastique  |                     Type:  defect
               Status:  new       |                 Priority:  normal
            Component:  avformat  |                  Version:  1.2.1
             Keywords:            |               Blocked By:
             Blocking:            |  Reproduced by developer:  0
Analyzed by developer:  0         |
----------------------------------+----------------------------------
 In our application, we write mp4 files through libav 9.6 using its public
 API. In one particular case we mux h264 video and AAC audio into the file,
 so the code is roughly like this:

 {{{
 AVFormatContext* m_av_format_ctx = ...;

 AVCodec* video_codec = NULL;
 AVCodec* audio_codec = NULL;

 CodecID codec_id = AV_CODEC_ID_H264;
 video_codec = avcodec_find_encoder(codec_id);

 m_av_format_ctx->oformat->video_codec = codec_id;
 m_av_format_ctx->video_codec_id = codec_id;
 AVStream* av_stream = avformat_new_stream(m_av_format_ctx, NULL);
 av_stream->id = 0;

 av_stream->r_frame_rate = av_d2q(m_video_info->fps, std::numeric_limits<
 unsigned short >::max());
 av_stream->time_base.num = av_stream->r_frame_rate.den;
 av_stream->time_base.den = av_stream->r_frame_rate.num;

 av_video_codec_ctx = av_stream->codec;
 // av_stream->codec initialization skipped...
 av_video_codec_ctx->codec_type = AVMEDIA_TYPE_VIDEO;
 av_video_codec_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
 av_video_codec_ctx->time_base = { 1, 1000 };


 codec_id = AV_CODEC_ID_AAC;
 audio_codec = avcodec_find_encoder(codec_id);

 m_av_format_ctx->oformat->audio_codec = codec_id;
 m_av_format_ctx->audio_codec_id = codec_id;

 AVStream* av_stream = avformat_new_stream(m_av_format_ctx, NULL);
 av_stream->id = 1;

 av_audio_codec_ctx = av_stream->codec;
 av_stream->time_base.num = 1;
 av_stream->time_base.den = m_audio_info->sample_rate;
 av_audio_codec_ctx->codec_type = AVMEDIA_TYPE_AUDIO;
 av_audio_codec_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
 av_audio_codec_ctx->time_base = { 1, 1000 };
 }}}

 (Sorry, I cannot post the complete code)

 Our internal video and audio timestamps are in milliseconds, but for audio
 we convert them to the sample rate-based values by calling
 av_rescale_rnd(). Video timestamps are converted to frame number (since
 for fixed-fps media we must specify time_base as 1/fps).

 The files are written ok by libav 9.6 this way, but not by ffmpeg 1.2.1
 (our code is unchanged). Files written by ffmpeg are not playable, video
 frame rate is extremely low (about 1 frame per several seconds). I have
 attached files written by libav and ffmpeg.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2658>
FFmpeg <http://ffmpeg.org>
FFmpeg issue tracker