[FFmpeg-user] ffmpeg compand knobs problem

Beeblebrox zaphod at berentweb.com
Fri May 16 18:30:14 CEST 2014

I decided to try a run without the compand or volume knobs, on the full
video (not a section):
$ ffmpeg -i day7.mpg -c:a libfdk_aac -c:v libx264 -preset slow -crf 32 -f
mp4 day7.mp4
The resulting video has very high level of background static noise and none
of the speech can be understood. I would speculate that compand in fact did
a fantastic job of reducing the static to the point that when used, speech
was at least comprehensible.

I decided to further diminish the problem and made a run where audio was
not touched at all. ($ ffmpeg -i day7.mpg -c:v libx264 -preset slow -crf 32
-f mp4 day7.mp4). The result was the same - high level background static.

Is ffmpeg affected by microphone input settings in mixer (oss)? Where does
the static input come from? Does ffmpeg use the sound card for any of the

Thanks and Regards.

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