Skipping audio

[Ariff Abdullah]

Below are my recommendations. Please follow from top-to-down. You
don't have to follow it untill the end if (say like) step #1 solves
your problem. Even so, I would say that step #7 quite mandatory for
multimedia environment (perhaps all of it).

On Wed, 15 Mar 2006 15:30:13 +0000
Baldur Gislason <baldur at foo.is> wrote:
> I'm using VLC media player to play sound, the output goes through
> enlightenment sound daemon.
> 

1) Try to avoid esound like a plague. FreeBSD has it's own sound
   mixing infrastructure (call vchans/virtual channels). Try recompile
   your vlc with "make -DWITHOUT_ESOUND" and instead [..] (see below
   for vchan recommendation #4).
2) Use other much simpler, lightweight multimedia player like xmms,
   mplayer, etc. etc.

> 
> root at clippy:~# sysctl hw.snd
> hw.snd.report_soft_formats: 1
> hw.snd.targetirqrate: 32

3) hw.snd.targetirqrate=16

> hw.snd.verbose: 2
> hw.snd.maxautovchans: 0

4) hw.snd.maxautovchans=10 , so you won't end up with "device busy" in
   case 4 vchans are not enough.

> hw.snd.unit: 0
> hw.snd.pcm0.buffersize: 16384
> hw.snd.pcm0.vchans: 4

5) This should be ok.

> hw.snd.pcm0.ac97rate: 48000
> 

6) Route everything to "/dev/dsp" instead of "/dev/dspX.Y". Let the
   auto channel allocation do its job.

7) (kernel) Use SCHED_ULE instead of SCHED_4BSD, with PREEMPTION
   enabled. This is all about audio/multimedia responsiveness.


--
Ariff Abdullah
FreeBSD
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