[FFmpeg-user] Bug in FFMPEG Alsa?

Nicolas George george at nsup.org
Fri Feb 17 13:19:36 EET 2017


Le nonidi 29 pluviôse, an CCXXV, christina zou a écrit :
> 1. ffmpeg -f alsa -acodec pcm_s32le -i mic_sv temp.wav
> 
> 2. arecord -Dmic_sv -c2 -r48000 -fS32_LE -twav temp.wav
> 
> Command 1 takes 95% CPU and produces stuttery, clicky unusable audio.
> 
> Command 2 takes 5% CPU and produces perfect audio.
> 
> I'm on a Pi Zero. I compiled FFMPEG with ALSA support.
> 
> After a long chat in FFMPEG IRC, we believe there is something wrong with
> the way FFMPEG waits for ALSA packets. At the very least, FFMPEG waits for
> ALSA packets differently than arecord does.

Could you show us the output of the following command:

time ffmpeg -i temp_arecord.wav temp_ffmpeg.wav

... where temp_arecord.wav is the correct, non-stuttering file produced
by arecord?

And then the output of this one:

time ffmpeg -i temp_arecord.wav -c copy temp_ffmpeg2.wav

Regards,

-- 
  Nicolas George
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