Bug 99689 - Recording from monitor has glitches when playing other sounds.
Summary: Recording from monitor has glitches when playing other sounds.
Alias: None
Product: PulseAudio
Classification: Unclassified
Component: core (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium major
Assignee: pulseaudio-bugs
QA Contact: pulseaudio-bugs
Depends on:
Reported: 2017-02-06 06:38 UTC by Dario Nieuwenhuis
Modified: 2018-07-30 10:16 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:

tgz containing sine.wav, silence.wav, recorded.wav (2.13 MB, application/gzip)
2017-02-06 06:38 UTC, Dario Nieuwenhuis
glitches (72.35 KB, image/png)
2017-02-06 06:40 UTC, Dario Nieuwenhuis

Description Dario Nieuwenhuis 2017-02-06 06:38:35 UTC
Created attachment 129350 [details]
tgz containing sine.wav, silence.wav, recorded.wav

Attached in the .tar.gz are 3 files:
- sine.wav: 30-second sine wave
- silence.wav: 0.1-second silence
- recorded.wav: the glitched recorded result.

How to reproduce: 

- run: 
    paplay sine.wav
- While the sine wave is playing, in another terminal run:
    parec -d $MONITOR --file-format=wav > recorded.wav
where $MONITOR is your monitor device, in my case it's alsa_output.pci-0000_00_1f.3.analog-stereo.monitor
- While recording, in another terminal run: 
    paplay silence.wav
- stop parec with Control+C
- stop the paplay sine.wav
- Listen to recorded.wav: you should hear glitches similar to my recorded.wav. The sine wave plays, but really short periods of silence are inserted.

Some more interesting things: 
- If you play silence.wav many times, you get more glitches in the recording. Every play seems to trigger 1-2 glitches.
- Any sound playing triggers the glitches - system sounds for example.
Comment 1 Dario Nieuwenhuis 2017-02-06 06:40:26 UTC
Created attachment 129351 [details]

Added a screenshot of the waveform of the glitches.
Comment 2 Dario Nieuwenhuis 2017-02-06 06:44:17 UTC
These two old bugs seem to be related / the same:
Comment 3 Dario Nieuwenhuis 2017-10-11 18:54:01 UTC
Any news on this? I can still reproduce it on PulseAudio 11.0
Comment 4 Tanu Kaskinen 2017-10-15 13:29:16 UTC
No news.
Comment 5 GitLab Migration User 2018-07-30 10:16:47 UTC
-- GitLab Migration Automatic Message --

This bug has been migrated to freedesktop.org's GitLab instance and has been closed from further activity.

You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.freedesktop.org/pulseaudio/pulseaudio/issues/311.

Use of freedesktop.org services, including Bugzilla, is subject to our Code of Conduct. How we collect and use information is described in our Privacy Policy.