FYI group, Chris (the active maintainer of OpenAL Soft) has some troubles with the PA backend to OpenAL. I'd love to see the PA developers on this list to work with Chris and figure out where the problem is and resolve it, so that we don't have to resort to alsa-pulse, which I dislike for many reasons, not the least of which is the level of abstraction taking away some of the (ease of) configurability of native pulse. Aside from actually addressing Chris's technical issues with the pulse backend, I'd just like to chime in and say I have never experienced anything like this before, and I've used openal-soft's pulse backend on a pulse server with an uptime in excess of a month. So it clearly isn't the case that this behavior manifests in all situations. Depending on the version of alsoft and PA that I'm using vs. Chris's, it's either a regression he's experiencing (if his version(s) are newer), or I'm using a newer version of pulse that fixes the problem. I'm not sure. Or it could just be an alsa-driver-specific issue, as we have often discovered is at the root of many PA troubles. Thanks, Sean ---------- Forwarded message ---------- From: Chris Robinson <chris.kcat@xxxxxxxxx> Date: Mon, Feb 20, 2012 at 3:41 PM Subject: [Openal-devel] PulseAudio backend troubles To: openal-devel at opensource.creative.com Hi guys, I have a bit of a query. Currently, OpenAL Soft will prefer the PulseAudio backend when it's available. However, lately I've noticed that I end up getting a lot of breakup in playback when the PA server has been running for a while. Traces I've done have shown that Pulse is not running out of audio -- initial startup has it filling the whole buffer, and each update after correctly shows an approximate period-sized writable chunk which is only a fraction of the whole buffer. I've also notced that the ALSA->Pulse bridge seems to be working much better. I no longer have to explicitly disable mmap as it appears ALSA's mmap emulation is now off by default (it would break the pulse plugin when used), and audio playback doesn't break up. I've been considering dropping, or at least lowering the priority of, the PulseAudio backend in favor of the ALSA backend. However, I'm not sure if the mmap emulation bug is truly gone or if it's just my system and/or newer setups that work now. Also, the ALSA backend doesn't do as good of a job autodetecting the default output mode (eg, quad or 5.1 surround) like the PulseAudio backend does, especially with the pulse plugin (even without 'plug', it'll accept any output mode). So, I have a quandry. Do I leave the PulseAudio backend as it is, where it breaks when PulseAudio's minimum latency starts growing high (as it often likes to do)? Or do I lower its priority to prefer the ALSA backend and the pulse plugin, which doesn't do as good of a job in detecting the default audio config and may still have mmap issues for some people? Unless someone can take a look at OpenAL Soft's PulseAudio backend, I can't see anything that should be causing the breakup in playback as it's not underrunning. Of course when PulseAudio's minimum latency grows you'll start having a lot of audio lag anyway, which is bad either way I take it, and there's nothing OpenAL Soft can do for that (requires killing and restarting the pulse server to fix). Any ideas or suggestions? _______________________________________________ Openal-devel mailing list Openal-devel at opensource.creative.com http://opensource.creative.com/mailman/listinfo/openal-devel
