https://bugs.winehq.org/show_bug.cgi?id=46725
--- Comment #9 from Paul Gofman gofmanp@gmail.com --- (In reply to Ethan Lee from comment #8)
The 480 figure makes perfect sense; for whatever reason WASAPI likes to make the sample block size very specific depending on the device (for 48KHz it's 480, for 44.1KHz it's something even weirder like 520), which I suspect is what this game is doing for the mastering voice. The only question is, is it hardcoded and setting the sound card output to a different rate/configuration is enough to crash the game even on Windows (surprisingly likely), or is the game querying WASAPI directly to get the buffer size and allocating the buffer based on that... for FAudio I'm not sure what the correct solution is since the quantum is _supposed_ to be 512 by default (unless you specify XAUDIO2_QUANTUM_1024) but there isn't really anything in the spec that guarantees it, just an off-hand mention of a ~10ms update interval.
I changed frequency for audio device but it did not affect anything here: the processing buffer is still 480. Can it be that this size is related to input stream and not to the device? Or is that it is not related to the input / output streams at all but Win xaudio is calling _Process for parts of the buffer? Anyway, I really didn't look much into audio stuff yet and might be missing many important aspects.