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ALSA-JACK bridge produces bad clicks when stopping playback

Posted: Wed Aug 05, 2015 8:05 pm
by unfa
This happens randomly with about 20% chance. I can hear that when someone writes to me on Facebook and the page is not currently viewed. A sound notification is played and sometimes it's followed by a nasty click.

I captured it with jack_capture and I'm attaching an excerpt from that in 32-bit float. It exceeds 0 dB at certain places, but in a weird way - like it's been clipped at 0dB once, then resampled in 32-bit float where the inter-sample peaks / clipping ripples (the Gibbs phenomenon) appeared but the signal wasn't clipped again.

This didn't happen a few months ago, and I first noticed it on Soundcloud between tracks. However it seemed to happen just after certain tracks I uploaded (in FLAC) and every single time (or almost). It made me investigate my uploads in case I erronously left some high energy sample at the end of the track - I didn't find one.

Does anyone experience this too?

Re: ALSA-JACK bridge produces bad clicks when stopping playb

Posted: Thu Aug 06, 2015 12:53 am
by sysrqer
I also get this. I was asking on the irc about it the other day in fact but didn't get much of an answer. I have no idea what causes them though, really hoping someone here can shed some light on it.

Re: ALSA-JACK bridge produces bad clicks when stopping playb

Posted: Fri Aug 07, 2015 12:13 pm
by skavar
which bridge are you using?
I had some weird sound loops and whatnot using alsa jack plugin, but alsa loop jack is all good.

Re: ALSA-JACK bridge produces bad clicks when stopping playb

Posted: Fri Aug 07, 2015 4:03 pm
by sysrqer
Previously I have been using the alsa loop jack. I have just tried the alsa jack plugin and it seems a bit better than loop but I am still getting clicks, although less than before.
I would really like know what is causing them though, they don't register as xruns so I imagine it must be something on alsa's side rather than in jack.

Re: ALSA-JACK bridge produces bad clicks when stopping playb

Posted: Fri Aug 07, 2015 10:12 pm
by Shupacabras
Hi

Resolution rate change?

I have problems with SB Live

solution was to work at 48,000 Hz