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

[Tanu Kaskinen]

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.

-- 
Tanu