[FFmpeg-devel] [PATCH 2/4] fftools/ffmpeg_enc: only promote first frame side data to global when meaningful

[Andreas Rheinhardt]

Anton Khirnov:
> Quoting Andreas Rheinhardt (2024-03-23 14:15:06)
>> Anton Khirnov:
>>> Skip those side data types that do not make sense as global side data.
>>> ---
>>>  fftools/ffmpeg_enc.c | 5 +++++
>>>  1 file changed, 5 insertions(+)
>>>
>>> diff --git a/fftools/ffmpeg_enc.c b/fftools/ffmpeg_enc.c
>>> index f01be1c22f..6a91fd0398 100644
>>> --- a/fftools/ffmpeg_enc.c
>>> +++ b/fftools/ffmpeg_enc.c
>>> @@ -247,6 +247,11 @@ int enc_open(void *opaque, const AVFrame *frame)
>>>          enc_ctx->chroma_sample_location = frame->chroma_location;
>>>  
>>>          for (int i = 0; i < frame->nb_side_data; i++) {
>>> +            const AVSideDataDescriptor *desc = av_frame_side_data_desc(frame->side_data[i]->type);
>>> +
>>> +            if (!desc || !(desc->props & AV_SIDE_DATA_PROP_GLOBAL))
>>> +                continue;
>>
>> Why the first check? Is it intended that a defined side data type
>> doesn't have a descriptor? Because IIRC all side data types that can
>> occur here are defined and have not been created by letting the user
>> pass a number via options.
> 
> It shouldn't happen, but it's not inconceivable that e.g. a filter could
> attach side data with an unknown type to a frame. I can remove the check
> if you prefer it.
> 

Yes. I'd consider such a filter buggy and that bug should not be covered up.

- Andreas