[FFmpeg-devel] [PATCH] avformat/ivfenc: fix writing codec tag

[James Almer]

On 9/24/2018 2:54 PM, Jan Ekström wrote:
> On Mon, Sep 24, 2018 at 3:57 AM, James Almer <jamrial at gmail.com> wrote:
>> The value in AVCodecParameters->codec_tag may not be correct for IVF,
>> as it's the case when remuxing AV1 streams from mp4, so ignore it and
>> write the correct value based on codec ID instead.
>>
>> Signed-off-by: James Almer <jamrial at gmail.com>
>> ---
>>  libavformat/ivfenc.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/libavformat/ivfenc.c b/libavformat/ivfenc.c
>> index af803d59ee..66441a2a43 100644
>> --- a/libavformat/ivfenc.c
>> +++ b/libavformat/ivfenc.c
>> @@ -46,7 +46,7 @@ static int ivf_write_header(AVFormatContext *s)
>>      avio_write(pb, "DKIF", 4);
>>      avio_wl16(pb, 0); // version
>>      avio_wl16(pb, 32); // header length
>> -    avio_wl32(pb, par->codec_tag ? par->codec_tag :
>> +    avio_wl32(pb,
>>                par->codec_id == AV_CODEC_ID_VP9 ? AV_RL32("VP90") :
>>                par->codec_id == AV_CODEC_ID_VP8 ? AV_RL32("VP80") : AV_RL32("AV01"));
> 
> In the future we might want to make a mapping array, but for now this
> looks a-OK. Unfortunately the tags for AV1 do not match between IVF
> and ISOBMFF.

There is a mapping array, codec_ivf_tags[], but since av01 == AV01 when
doing a case insensitive check, par->codec_tag ends up as the former
when remuxing from mp4 to ivf, at least with ffmpeg.c

> 
> LGTM.

Pushed, thanks.

> 
> Jan
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