Re: Fwd: Re: Audio - In kernel audio mixing

[Brian Buhrow <buhrow%nfbcal.org@localhost>]

	hello.  I'll echo Brad's questions about latency and delay.  Delay,
when it comes to audio presentation, is bad.  I was recently at a talk
where the developer was discussing trying to synchronize one audio source
with another.  For their application, they're sending audio sources from
two locations over WiFi and other wireless technologies.  Their goal was to
make sure the sychronized audio was never more than 25ms out of sync, and,
hopefully, a lot less.  If my latency budget is only 50-100ms for a given
audio application, I'd hate to spend so much of that budget before I even
get out of the kernel.  I don't know what the latency is for the
traditional audio drivers is, but I can tell you it varies depending on the
driver in question.  For example, the auich(4) and emuxki(4) drivers are
very responsive with low latency.  However, the uaudio(4) driver exhibits
considerably more delay in its operation.  If these vaudio drivers are
slower than the uaudio(4) driver, then I'd suggest working to get that
delay down.  If that's just not feasible, then the traditional audio(4)
interface should remain viable for those of us who need very responsive
audio performance.

-thanks
-Brian