[pulseaudio-discuss] Crackling audio with Pulseaudio 4.0 and the simple Pulse API.

[Tanu Kaskinen]

On Wed, 2013-07-10 at 11:51 +0300, Tanu Kaskinen wrote:
> On Wed, 2013-07-10 at 11:28 +0300, Tanu Kaskinen wrote:
> > On Wed, 2013-07-10 at 11:12 +0300, Tanu Kaskinen wrote:
> > > On Wed, 2013-07-10 at 16:18 +1000, Luke Yelavich wrote:
> > > > Hey folks.
> > > > I've been experiencing some weird  and infrequent crackling of audio
> > > > with pulse 4, and applications that use the simple pulse API. The
> > > > crackling tends to happen at the very start of the buffer, causing a
> > > > varying amount of audio to be audible as noise, or not at all. This
> > > > doesn't occur when other applications are playing audio at the same
> > > > time, and it comes and goes, and I can never predict when it might
> > > > start to happen, or when it will go away. Unfortunately I haven't been
> > > > able to reliably log this, since it seems to occur very infrequently
> > > > if not at all whilst being logged with full verbose output.
> > > 
> > > If it doesn't happen when other applications are playing audio, it
> > > probably only happens when the device suspended prior to
> > > speech-dispatches starting to play it's audio. Reducing the suspend
> > > timeout from the default 5 seconds to 1 or 0 seconds may help with
> > > reproducing the issue more frequently. Setting the timeout to 0 seconds
> > > can be done by giving argument "timeout=0" to module-suspend-on-idle.
> > 
> > I now tried speech-dispatcher myself, and at least on my machine
> > speech-dispatcher creates a persistent stream, so the device never
> > suspends. My setup is Ubuntu 13.04 without any changes to
> > speech-dispatcher configuration. I started speech-dispatcher without any
> > command line arguments, and I tested "spd-say hello", which seems to
> > result in sound remotely resembling the word "hello", but the audio is
> > terribly crackly (I presume I'm seeing the same bug as you). The audio
> > is never clean, it doesn't matter whether something else is playing at
> > the same time or not.
> > 
> > My PulseAudio version is the current master branch head, I'll try next
> > with PulseAudio 3.0.
> 
> PulseAudio 3.0 seems to work fine. I guess it's time for bisecting...

This commit seems to break speech-dispatcher:
http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=30ce3a14e5ae1cd316a18bec95b831c07ac57a1a

I don't know yet what is wrong with the patch.

-- 
Tanu