[FFmpeg-devel] [PATCH] avcodec/mfenc: set frame size for audio encoders.

[Gyan Doshi]

On 2022-06-18 12:19 pm, Andreas Rheinhardt wrote:
> Gyan Doshi:
>> Default avctx->frame_size is 0 which leads to init failure for
>> audio MediaFoundation encoders.
>> ---
>>   libavcodec/mfenc.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/libavcodec/mfenc.c b/libavcodec/mfenc.c
>> index 13ed7b3e11..ff9ffe4827 100644
>> --- a/libavcodec/mfenc.c
>> +++ b/libavcodec/mfenc.c
>> @@ -1066,6 +1066,9 @@ static int mf_init_encoder(AVCodecContext *avctx)
>>   
>>       c->main_subtype = *subtype;
>>   
>> +    if (c->is_audio && !avctx->frame_size)
>> +        avctx->frame_size = 1024;
>> +
>>       if ((ret = mf_create(avctx, &c->functions, &c->mft, avctx->codec, use_hw)) < 0)
>>           return ret;
>>   
> 1. You forgot to mention the ticket that this is supposed to fix; you
> should also add that this a regression and the commit
> (827d6fe73d2f5472c1c2128eb14fab6a4db29032) that supposedly introduced
> the regression (if this is indeed true).
  I initially became aware due to a user query. Saw ticket later. Will 
add details.

> 2. Where does this number come from (apart from the user-provided error
> message)? How did it work before said commit?
> (It seems that frame_size was unset before this commit, but did it
> somehow just not matter?)

The MF encoders accept any number of samples per frame. They reframe as 
necessary for DSP.
I choose 1024 as its the most common frame size emitted (PCM/AAC decoders).

Regards,
Gyan