[pulseaudio-discuss] How to check visually for XRUNs/drop-out/interruptions and similar in PulseAudio?

Tanu Kaskinen tanuk at iki.fi
Wed Nov 8 11:43:53 UTC 2017

On Tue, 2017-11-07 at 15:29 +0100, 21naown at gmail.com wrote:
> If you cannot be 100% sure, is any problem replaced by a 0dB sound? If 
> so, then I can check for a possible problem with Audacity and 
> Sample Data Export. For example, if an underrun or a rewind occurs, is 
> it replaced by 0dB by PulseAudio? Or it is a random value?

If an underrun happens inside PulseAudio (i.e. an application doesn't
provide data fast enough), the missing audio is replaced with silence.

The issues with rewinds were about monitor sources and resampling. If I
understood correctly, your source material is in 48000 Hz and Jack is
configured with that rate too, so there's no need for resampling, and
you haven't mentioned recording from a monitor source either, so there
should be no reason to be concerned about rewinds. If rewinds happen,
they shouldn't cause any glitches.

But if you're curious, the monitor source bug causes short chunks of
audio to be duplicated in the recording stream. I haven't seen concrete
examples of what kind of glitches resamplers can have, but my intuition
is that one sample in the audio stream might have a significant
adjustment towards zero, and a few samples after that might have
slightly wrong values.



More information about the pulseaudio-discuss mailing list