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

Tanu Kaskinen tanuk at iki.fi
Tue Nov 7 11:31:46 UTC 2017

On Tue, 2017-11-07 at 00:30 +0100, 21naown at gmail.com wrote:
> Le 06/11/2017 à 11:00, Tanu Kaskinen a écrit :
> > On Sun, 2017-11-05 at 19:23 +0100, 21naown at gmail.com wrote:
> > > Le 05/11/2017 à 10:54, Tanu Kaskinen a écrit :
> > > > The alsa sink will log "Underrun!" if PulseAudio doesn't write fast
> > > > enough to alsa, but if you're only using jack as the output in
> > > > PulseAudio, then that's irrelevant.
> > > > 
> > > > Other modules that maintain their own buffers may also have underrun or
> > > > overrun situations. I don't have a comprehensive list of them. I know
> > > > module-loopback logs "Could not peek into queue" when it has an
> > > > underrun in its buffer.
> > > 
> > > PulseAudio may have an overrun/underrun problem like jack/QjackCtl may
> > > also be concerned, right?
> > 
> > Sorry, I don't understand this sentence.
> I would just like to be sure jack/QjackCtl may have overrun/underrun 
> problems, but forget that since you have already well answered to this 
> question with “Other modules that maintain their own buffers may also
> have underrun or overrun situations”. Sorry for this.

I'm still a bit confused. "Other modules that maintain their own
buffers may also have underrun or overrun situations" referred to
PulseAudio modules, so that sentence had nothing to do with
Jack/QJackCtl. Jack and QJackCtl are not PulseAudio modules. Jack can
have underruns, which you won't see in PulseAudio logs. QJackCtl can't
have underruns, because it's not streaming any audio, but QJackCtl can
be used to show the count of underruns in Jack.

If module-jack-sink is too slow to provide audio to Jack, that will
show up as an underrun in Jack.

> > > Are there other things similar to a drop-out in PulseAudio (if its
> > > resampling is disabled)?
> > 
> > I already answered this question in my last mail as well as I can.
> Does your sentence mean “There are no other problems which may modify 
> your sound with your configuration on the side of PulseAudio”? (= you 
> are sure there are no other problems)

I listed all problems that I could think of. I have 76% confidence that
there can't be any other problems.

I gave some bad advice, though:

> "Actual underrun of 'application name'" will be logged when a playback
> application fails to provide data to PulseAudio fast enough.

That message will show up in the log only with the alsa sink. With the
jack sink look for this message instead: "Implicit underrun of
'application name'".



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