[Freeswitch-users] How to avoid clipping when transcoding to PCMA/U ?

[David P]

Our conference.conf.xml had:

      <param name="comfort-noise" value="false"/>

and no auto-gain-level. I changed it:

      <param name="comfort-noise" value="0"/>
      <param name="auto-gain-level" value="-2000"/>

And there's now clipping only during the loudest parts. But I think this
gain setting is already extreme and I'd like to know if there's a less
brute-force way to eliminate clipping.

On Wed, Sep 9, 2020 at 9:33 AM David P <davidswalkabout at gmail.com> wrote:

> When we configure FSv10.4 to transcode Opus to PCMA/U, the output stream
> always has clipping (peak amplitude is always -0.17dB, 0.99 linear when
> measured in Audacity).
>
> I tried configuring opus.conf.xml as suggested in
> https://serverfault.com/a/807070 (with restart via: fs_cli -x 'fsctl
> shutdown elegant restart') but it makes no difference.
>
> When we simultaneously record the session with Audacity clientside, less
> than half the available range is used, so the user mic doesn't have gain
> too high.
>
> How can we avoid clipping when transcoding?
>
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