[pulseaudio-discuss] PA volume effects

[Lennart Poettering]

On Mon, 27.04.09 18:18, Daniel Mack (daniel at caiaq.de) wrote:

> I'm observing strange audio artefacts with my audio driver which seem to
> be related to audio material overamplification. IOW, the effect is only
> audible at waveform peaks. When I attenuate the playback volume
> pavucontrol, things get a lot worse - horrible distortion all over
> the place, even in more quite audio sections.
> 
> Also, when comparing the audio output of 'aplay -Dpulse foo.wav' with
> 'aplay -Dplughw foo.wav', it is clearly audible that PA adds some kind
> of amplification to the material (I would guess ~3dB), even though all
> GUI accessible levels are set to 100%.
> 
> The driver I'm working on does not have any volume control features,
> hence this must be done in software.
> 
> Has that been encountered before?

Please try to reproduce this, then do "ls" in pacmd and paste it
somehere. This should show if PA does digital amplification for any of
the active streams.

Lennart

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net         ICQ# 11060553
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