Re: [hatari-devel] Regression in Falcon sound

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On Fri, 12 Apr 2024 at 20:39, Nicolas Pomarède <npomarede@xxxxxxxxxxxx> wrote:
I confirm I get the same result as you did, there's some kind of
randomness that makes it a little more difficult to reproduce exactly on
every run.

For now, I don't know why there's this regression but as it involves DSP
it's not sure that it's related to the very recent changes I made to DMA
audio.

I will try to get some time to bisect, but even so this could imply
quite some changes, as Falcon audio still uses some "float" types to mix
at different frequencies and this can give too much rounding errors that
accumulate over time and can cause drift or "jump" in the sound buffer.
The plan is to replace this with integer math that "self adjusts" over
time to keep rounding unnoticable (as done for YM2149 and STE/TT audio)

It's quite possible it will be fixed after Hatari 2.5 is released, else
I'm afraid this would postpone the release for too long :(
Concerning the release, wouldn't it be wiser to revert all that recent DMA changes before release? If I understand the situation correctly, none of the things reported by Anders were happening before and the changes were introduced because of my obscure test case (which was wrong code anyway which just happened to work on real hardware).

--
http://mikro.atari.org


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