i810 audio fixes 1/2

Ove Kaaven ovek at arcticnet.no
Sat Mar 27 21:31:01 CST 2004

lør, 27.03.2004 kl. 20.40 skrev Mike Hearn:
> On Sat, 27 Mar 2004 14:36:31 -0500, Robert Reif wrote:
> > Another problem is that drivers support different formats in different  modes.
> > Because of software emulation in alsa, a driver may appear to support any
> > format but then fail when you try to mmap it because then software conversions can't
> > come into play.  
> I talked with one of the ALSA developers on IRC a day or two ago, and he
> appeared to think mmap would work regardless of what plugin chain was in
> use (resampling/conversion is implemented in alsa plugins). He said if it
> didn't work it was a bug.

Only if you don't use kernel-level OSS emulation or the "hw" alsa
device, I think. If you use alsa with the "default" or "plughw" devices,
plugins will resample for you (and those plugins are able to "fake"
mmaps). I'd think it's probably not a good idea to use ALSA plugins
instead of Wine's own resampling functions, though.

> IIRC in XP DirectSound primary buffers no longer correspond to the sound
> cards memory, they are just like any other and sent to the XP kernel
> mixer. Is it possible the same is now true of ALSA?

You can still go straight to the card's DMA buffer if you avoid plugins
(either by setting a sample rate that matches the card's, or by using
the "hw" device... and you probably need the latter anyway to find out
which sample rates the card supports).

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