[FFmpeg-devel] [PATCH] avformat/matroskadec: ignore CodecPrivate if the stream is VP9

[James Almer]

On 2/19/2018 11:37 AM, Carl Eugen Hoyos wrote:
> 2018-02-17 3:35 GMT+01:00 James Almer <jamrial at gmail.com>:
>> Defined in a recent revision of https://www.webmproject.org/docs/container/
>>
>> Signed-off-by: James Almer <jamrial at gmail.com>
>> ---
>>  libavformat/matroskadec.c | 4 ++++
>>  1 file changed, 4 insertions(+)
>>
>> diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
>> index cda8df2213..edc4f5d476 100644
>> --- a/libavformat/matroskadec.c
>> +++ b/libavformat/matroskadec.c
>> @@ -2397,6 +2397,10 @@ static int matroska_parse_tracks(AVFormatContext *s)
>>                  return ret;
>>          } else if (codec_id == AV_CODEC_ID_PRORES && track->codec_priv.size == 4) {
>>              fourcc = AV_RL32(track->codec_priv.data);
>> +        } else if (codec_id == AV_CODEC_ID_VP9 && track->codec_priv.size) {
>> +            /* we don't need any value stored in CodecPrivate.
>> +               make sure that it's not exported as extradata. */
>> +            track->codec_priv.size = 0;
> 
> You could add information about what this patch fixes to
> the commit message.
> 
> Carl Eugen

It prevents loading the contents of CodecPrivate into extradata for a
codec that doesn't need nor expect any. It will among other things
prevent said matroska specific binary data from being dumped onto other
formats during remuxing.
I'll add a line explaining the above to the commit message before pushing.