[SDL] ALSA/OSS linux audio driver priorities

[Gerry JJ]

Den Wed, 08 Aug 2007 07:18:27 +0100
skrev Sitsofe Wheeler <sitsofe at yahoo.com>:
> Something (an issue with either a driver/dmix/sdl or combination of
> the previous pieces) is still here. See
> https://bugs.launchpad.net/ubuntu/+bug/66483 .

That's interesting.  They describe lower sound quality and crackling
problems with ALSA (buffer overruns?  seems to be more than just that
though), which is exactly the kind of thing I've seen with ALSA's OSS
emulation (but not pure ALSA).  I've also reproduced this without using
SDL_mixer, playing a simple square wave with pure SDL audio.  The thing
is, they (in that link) seem to have tracked the issue down to dmix
(also see<https://bugtrack.alsa-project.org/alsa-bug/view.php?id=3253>)
but the OSS emulation doesn't use dmix unless the program using OSS is
run through aoss, which I didn't do when I tested this.  I think it's
definitely the same issue though, since the symptoms are the same and
the system does use the intel8x0 driver.

So anyways, if it's a low-level driver issue, favouring OSS over ALSA
in SDL wouldn't really fix things with ALSA's OSS emu since the problem
goes deeper than that.  It does seem to be more common with ALSA though.
On the other hand again, there's still the blocking-sound-in-other-apps
issue.  Sigh.

- Gerry