[stella] emulator/monitor synchronisation

Subject: [stella] emulator/monitor synchronisation
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Sun, 23 May 2004 00:48:52 +0200
> I wish emulators could really try hard to lock their refresh to monitor
> refresh.  If you are at some odd monitor refresh rate, figure out the best
> interval to refresh the display to avoid artefacts.

Unfortunately there is no 'best' interval to refresh the display
when the emulator and the monitor run at a different frame rate.
There always would be artefacts.

> If an emulator has the ability to pick a custom screen resolution and
> refresh, then it should try to set the PC monitor to 60fps (assuming NTSC)
> and lock the emulation directly to the monitor.  That's as close as you
> going to come to the real thing, I think.

The DOS versions of PCAE, Stella and z26 did that. But on
operating systems with less control over the hardware things
are not as easy. The SDL for example doesn't provide a way to
set the monitor refresh rate, because it's not possible to
do that on many of the systems that it supports. Therefore
Stella and z26 aren't able to do that anymore.

On some ports of the SDL it is possible to synch to the
monitor, so the Windows version of z26 still allows that
with the -r command line switch (without any parameters).
But then z26 will run at whatever frame rate is the default
for the selected video mode, which usually is higher than

I think for Windows XP there are several tools that allow
you to enforce a certain frame rate in DirectX on a mode
by mode basis. So theoretically you could set the frame
rate for the mode that you are using with z26 to 60 Hz.
Then there wouldn't be any artefacts in NTSC games anymore.
That's not an ideal solution, but probably as good as it gets
at the moment, if you want emulators to be portable.

Ciao, Eckhard Stolberg

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