[FFmpeg-devel] [PATCH 4/4] avformat/wavdec: dynamically set max_size by default

Marton Balint cus at passwd.hu
Sat Mar 2 00:30:59 EET 2024



On Thu, 29 Feb 2024, Marton Balint wrote:

>
>
> On Thu, 29 Feb 2024, Andreas Rheinhardt wrote:
>
>>  Marton Balint:
>>>  The wav demuxer by default tried to demux 4096-byte packets which caused
>>>  packets with very few number of samples for files with high channel
>>>  count.
>>>  This caused a significant overhead especially since the latest ffmpeg.c
>>>  threading changes.
>>>
>>>  So let's use a similar approach for selecting audio frame size which is
>>>  already
>>>  used in the PCM demuxer, which is to read 25 times per second but at most
>>>  1024
>>>  samples.
>>
>>  1024 samples seems to be quite small, in particular for files with few
>>  channels (like stereo).
>
> 1024 is kind of a historical default. Also having multiples of 1024 is 
> beneficial for some codecs which encode this many samples per frame.
>
> In any case, I am not against somewhat increasing this, but it should be done 
> for both PCM and WAV, it can be a separate patch and discussion.

I will apply this set soon unless there are other comments. Will send a 
patch after that to increase the default sample amount for wav and pcm.

Regards,
Marton


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