[FFmpeg-trac] #6301(avformat:new): Bitstream filter 'h264_mp4toannexb' isn't auto-inserted for hls muxer

FFmpeg trac at avcodec.org
Thu Apr 13 17:16:20 EEST 2017

#6301: Bitstream filter 'h264_mp4toannexb' isn't auto-inserted for hls muxer
             Reporter:  Alexander    |                    Owner:
                 Type:  enhancement  |                   Status:  new
             Priority:  wish         |                Component:  avformat
              Version:  git-master   |               Resolution:
             Keywords:  hls          |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |

Comment (by Cigaes):

 I think you misunderstand how it works. The HLS muxer does not know
 anything about your input or your output, that is the responsibility of
 your program. Therefore, adding "from input stream to output stream" to
 the documentation would be nonsense.

 The HLS muxer only sees the streams you want to mux. These streams can be
 in various formats, including:
 * H.264-in-Annex_B-format (stand-alone packets, no extradata);
 * H.264-in-MP4-format (slightly smaller packets, extradata).

 If you are providing H.264-in-MP4-format without the extradata, you are
 providing invalid input to the muxer, exactly as if you filled the
 packets' data with random octets.

 Now, where does the extradata come from? The same place as the packets'
 data, and the demuxer does not care.

 If the packets come from FFmpeg, a demuxer or an encoder, then the
 extradata is there too, because FFmpeg does things correctly, or more
 precisely consistently.

 If the packets come from anywhere else, then that is your responsibility
 to make sure they come with their extradata.

Ticket URL: <https://trac.ffmpeg.org/ticket/6301#comment:10>
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