[FFmpeg-trac] #6156(undetermined:reopened): Issue with FFMPEG ALSA CPU usage

[FFmpeg]

#6156: Issue with FFMPEG ALSA CPU usage
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             Reporter:  mushm0m      |                    Owner:
                 Type:  defect       |                   Status:  reopened
             Priority:  normal       |                Component:
              Version:  git-master   |  undetermined
             Keywords:  alsa         |               Resolution:
             Blocking:               |               Blocked By:
Analyzed by developer:  0            |  Reproduced by developer:  0
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Comment (by kainz):

 Replying to [comment:7 cehoyos]:
 > Replying to [comment:5 kainz]:
 > > So on a pi0w using a similar setup, but with a PCM line mic that i've
 got rigged to show up as a alsa PCM capture device @48000/s16le, I can
 absolutely reproduce the CPU usage issue when running `ffmpeg -f alsa -i
 default -acodec pcm_s16le out.wav`
 >
 > Please confirm that the issue is not reproducible with `arecord`.

 `arecord -D hw:0 -c 2 -f S16_LE -r 48000 out.wav` uses approximately
 0.7-1% cpu on the pi0w, as does using `-D default`.

 I get the pegged CPU on ffmpeg using either `-i default` or `-i hw:0` on
 ffmpeg.

 So, I just tested with pulseaudio as well now, ensuring that I have
 pulseaudio daemon's default sample rate set to 48k.  This gives me `ffmpeg
 -y -f pulse -i default -r 48000 out.wav` results of 1.6% CPU use on ffmpeg
 and 0.7% cpu use on pulseaudio, as well.

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Ticket URL: <https://trac.ffmpeg.org/ticket/6156#comment:8>
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