Dmix (Fedora Core 4)

[Sitsofe Wheeler]

On Sun, 2005-01-16 at 14:27 +0100, Ralf Ertzinger wrote:
> pcm.!default {
>     type plug
>     slave.pcm "asym"
> }
> 
> into either ~/.asoundrc or /etc/asoundrc. Previous alsa versions use
> dmix instead of asym, but do not get recording abilities on the default
> device.

I believe the above already works with FC3 and allows full duplex
(record and playback at the same time) PCM but does not address the need
for software mixing of multiple output streams (e.g. the case of playing
music while still hearing IM event sounds) which is what I'm thinking of
(although please correct me if I am wrong).

By enabling dmix on *those cards that need it* (why waste CPU on cards
that can already handle this?), existing software mixers like esound can
be phased out for local mixing in favour of alsa mixing. I may have bad
configuration but dmix produced superior results to esound when playing
the SDL game rRootage (which plays music and sound effects at the same
time). The quality sounded better and the sound did not lag 2 seconds
behind the action. 

However setting up dmix appropriately seems to vary from card to card
and many apps (bzflag, helixplayer) are still stuck with only OSS
output. Moving these apps over to alsa (or perhaps esound if they want
to support legacy mixing/network sound) would be sensible.