Re: 2.5.74-mm1

Davide Libenzi
2003-07-08T00:22:18Z

On Tue, 8 Jul 2003, Daniel Phillips wrote:

> On Tuesday 08 July 2003 00:03, Davide Libenzi wrote:
> > > > Try to play with SNDCTL_DSP_SETFRAGMENT. Last time I checked the kernel
> > > > let you set a dma buf for 0.5 up to 1 sec of play (upper limited by
> > > > 64Kb). Feeding the sound card with 4Kb writes will make you skip after
> > > > about 50ms CPU blackout at 44KHz 16 bit. RealPlayer uses 16Kb feeding
> > > > chunks that makes it able to sustain up to 200ms of blackout.
> > >
> > > That's just fiddling, it doesn't deal with the basic problem. Anyway,
> > > big buffers have their own annoyances. Have you tried the graphic
> > > equalizer in xmms lately? A one second lag on slider adjustment is not
> > > nice.
> >
> > That's not fiddling. It is tuning your app so that it won't require
> > realtime when it is not needed.
>
> But realtime is needed, because there is a deadline for each buffer-fill.

Yes, in theory it is needed since you have to meet a deadline. But if
you program you timings such that your deadline is 400-500ms it is really
hard to lose it against one of 50-100ms.

- Davide