[MPlayer-dev-eng] audio_out.c question

[Rich Felker]

On Wed, Mar 22, 2006 at 10:09:59PM -0500, Mitch Golden wrote:
> I would point out is that it's not artsd that takes control of /dev/dsp, 
> but rather that no two applications can have /dev/dsp open at once - not 
> even two separate instances of mplayer.  In that regard, the thing that is 
> broken is OSS really.

No, it's an underlying limitation of the hardware. If you want
multiple programs playing audio at the same time, get hardware that
supports this. In sane users' minds this is useless though. Why would
you need to play and mp3 and a movie at the same time? You'll just
mess up your ability to hear either.

> As I understand it, that issue was one of the major 
> reasons that alsa was written.

ALSA's dmix is much more broken. It does resampling and mixing behind
the user's back, forking behind the calling program's back which
introducing all sorts of bugs, and breaks A/V sync.

> Is there any issue with using alsa in preference to OSS, at least for 
> audio only files?

Yes. ALSA will use dmix, etc. crap. The OSS emulation layer is immune
to all these userspace hacks and thus is not buggy.

> As you say, artsd is not necessary and doesn't improve 
> anything, so keeping it at the bottom of the list is fine.  Does alsa 
> cause the desync problem as well?  My understanding is that it's 
> implemented at the kernel level just as OSS is.

Without dmix it's kernel level only, but then you lose the only
advantage you wanted.

> I could also improve the message when it does crash on unpause, so that 
> it's clear that what happened is that some other application has grabbed 
> the audio device.

Yes this would be a nice change.

Rich