Re: [stella] 2600 Sound, that time of year..

Subject: Re: [stella] 2600 Sound, that time of year..
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Fri, 1 Aug 2003 14:43:21 +0200
> That's weird it sounds truly dire on z26 here, and it plays a different
> speed.. Your 2600 recording is exactly the same speed as my sound emu, but
> z26 here plays much faster.. I've tried all sorts of parameters, sound
> buffer sizes, different refresh modes, but even full screen @60 hz and
> default sound buffer sizes it sounds terrible..

z26 does emulate digitized sound properly. The reason why your program
still fails is because you don't do any VSYNC yet. There is a small
oversight in the way how we calculate the frame rate. If the emulator
has to interrupt the frame on it's own, because the game doesn't do
a VSYNC in time, we forgot to update the line number counter. Therefore
z26 creates sound buffers for a frame with 320 scanlines in your
demo, but doesn't wait long enough to have them fully played.

This will be fixed in the next version of z26. Until then you can use
the -r49 command line switch. This will force the correct frame rate
for your demo. Additionally you can try to adjust the sample buffer
size, if you still have problems on your system.

If you find any other bugs in z26, it would be nice, if you could
provide us with source code as well as a binary of the program that
doesn't work properly. That makes it easier for us to find out what's
going wrong. Also it would increase your chances that someone might
suggests things to you like properly initializing the VCS. ;-) In
your current demo you don't seem to initialize anything. You just
rely on the default state of the VCS. While this properly set for
sample playback in the emulators and the CC/SC, that might not be
the case with a normal cartridge on a real system.

On your debugger question:
If the trace feature in z26 doesn't help you to find your bug, you
could try PCAE. It has a simple debugger that provides most of the
features from your withlist.

On posting your sound emulator here:
Generally there are no problems with posting programming tools
here. But I think there is an attatchment size limit of 100kb
or so. So if your ZIPed tool is too big, it might be better to
provide a download link for your webside.

Ciao, Eckhard Stolberg

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