[FFmpeg-devel] [PATCH v2] movenc: Use first H264/HEVC frame as extradata, if it is missing

[Martin Storsjö]

On Thu, 21 May 2020, Jan Ekström wrote:

> On Thu, May 21, 2020 at 2:00 PM Martin Storsjö <martin at martin.st> wrote:
>>
>> Oh, indeed, you're right.
>>
>> However wrong that is from the mov/mp4 point of view, it may very well be
>> that AVC intra is supposed to be written like this in mov/mp4 files - but
>> we'd need a word from somebody who actually knows that case.
>>
>
> The best way to figure out if a user wants to do AVC Intra muxing
> would be to either a) require specific codec_tag/muxing mode be set by
> user or b) attempt to somehow properly check the actual bit stream
> within `mov_get_h264_codec_tag` to make the selection proper. Right
> now the system seems to base that if you are doing H.264, and have no
> codec_tag set already, then `mov_get_h264_codec_tag` attempts to set
> an AVC Intra codec_tag (which hits TAG_IS_AVCI), which then attempts
> to mux things in that proprietary way.

Thanks for the insight into this case, that it really is intended to mux 
it this way.

I hadn't known what TAG_IS_AVCI is really, but with that it should be easy 
to fix this case.

// Martin