[MPlayer-dev-eng] audio_out.c question

[Clemens Ladisch]

Rich Felker wrote:
> 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.

Some users want to hear "You have new spam^Wmail" notifications when
playing other sounds.

The multi-stream capability of most sound cards is just a side effect of
the wavetable synthesizer that must be able to play several instrument
voices at once.

> > 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,

We don't have much choice in this -- the wailing and gnashing of teeth
would be much louder if we didn't use dmix by default on most sound
cards.

> forking behind the calling program's back which
> introducing all sorts of bugs, and breaks A/V sync.

Bug number?

> > 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.

Except when using aoss.  And you know that we're planning to redirect
OSS emulation devices back to userspace so that we can inflict the same
features on them?  ;-)


Regards,
Clemens

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