Trying to get optimal sound settings for OpenMSX in Windows

By Samor

Prophet (2162)

Samor's picture

24-10-2022, 12:29

The following might be very hardware-specific, but I'm trying to get good sound settings for OpenMSX on Windows, and while that mostly worked out, I still have a few questions and some findings that I find a bit weird.

First, the OpenMSX manual hints there is a directsound driver which should be the default in Windows, but it defaults to SDL (at least, that's what the set sound_driver command tells me) and I can't find one for direct sound. Maybe this is old information in the manual?

That aside, I've found some behaviour in OpenMSX (pretty much every recent version I tried) on Windows 10 and 11 that is a bit curious.

The default setting for samples is 2048. While the sound is fine with that, screen movement (scrolling) will usually appear jerky (depending on machine configuration it happens more or less often); I can even set the samples much lower, same result.
When I change samples to 2049 (yes, just 1 higher) the scrolling will be fine 9 out of 10 times.
It being smooth or jerky is always something that is determined when the emulator starts, it does not change during emulation unless I change the samples.
Occasionally scrolling will still be jerky with the 2049 setting (or a higher value, like 4096), what I do then is change it to a lower setting like 2048 (stays jerky), back to 2049 and it will be smooth once more.
(Maybe I am understanding this setting wrong and 2049 and 4096 essentially do the same? That would explain a lot.)

Having to change the samples every so often is just a minor inconvenience, but I thought this behaviour was strange enough to share it here.
Ideally I'd like to set samples much lower while keeping performance, but maybe that's just not possible.

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By Manuel

Ascended (19053)

Manuel's picture

24-10-2022, 19:39

The samples setting should not influence scrolling smoothness... Don't know what is going on.

I hope I remember to check the manual on that sound driver. It was indeed removed a few years ago.