Re: [stella] Announce: z26 on Linux!

Subject: Re: [stella] Announce: z26 on Linux!
From: Stephen Anthony <stephena@xxxxxxxxxxxxxxxxxxxxx>
Date: Sun, 18 Apr 2004 00:48:03 -0230
On April 17, 2004 09:16 pm, B. Watson wrote:
> On Sat, 17 Apr 2004, John Saeger wrote:
> > I wonder if the *low-latency* 2.6 kernel with the *advanced sound
> > architecture* would make a difference?  Has anybody tried anything
> > on that?
> ALSA works a lot better, yes. Even ALSA's OSS emulation mode is a lot
> better on my hardware than OSS by itself.
> BTW, for those still using 2.4 kernels, you can use ALSA on 2.4 as
> well.

I've been using ALSA since sometime in the 2.4 kernel (currently using 
2.6.4), and it's always worked great.  I once had an ALSA-specific 
backend (in Stella version 1.3), but I'll be discontinuing it for 
future releases since using SDL and setting SDL_AUDIODRIVER=alsa works 
just as well.  Just make sure you have at least SDL version 1.2.7, 
since it fixes a blocking problem in the ALSA sound code.

Bryan, John, or whoever, I'm very interested in speaking with you 
concerning sound issues in both Stella and z26.  The sound problems are 
what's delaying the next Stella release, and sound programming isn't my 
best area.  I really &##*$ hate sound programming.

Specifically, I notice that z26 for Windows uses a sound queue.  This 
queue is filled as it becomes empty, and the SDL audio callback empties 
it as required.

I had a similar queue in Stella, but the strange thing is if I change 
the queue size, the sounds would become 'stretched out'.  This didn't 
happen in z26.  For now, I've removed the sound queue from Stella 
altogether, and let the SDL audio callback throttle the sound.  The 
problem is that I have to keep the fragment size at 512, or else the 
sound becomes stretched out again.

In the current Stella code, changing fragment size and/or sample rate 
makes the sound generation go way off.  This shouldn't happen, and it 
doesn't happen in z26.  If you read my previous message, I'm looking 
for the 'magic' code that let z26 work correctly.


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