Hmmm, I would love to explain! But I'm not sure how best to do it so I have attached an audio recording from a game if that helps! As well as a screenshot of how the audio looks. The hiccups are clearly visible there.The way Raspberry Pi 5's video out is specified you only get an interrupt and a page flip once per frame, not once per field. Now the interrupt could be faked, but the page-flip rate limitation can't be worked around.
If you're displaying a single frame-buffer then it should in theory be possible to for software to arrange to synchronize updates to 60fps, but using DRM it will be limited to 30fps. I don't know what Retroarch does (I guess I should find out!)
Can you explain the hiccup with 240p? It shouldn't happen. Maybe it's because the frame rate is not exactly 60Hz (which it never is with NTSC, but Pi 5's 240p currently runs at 59.363Hz rather than the more common 60.055Hz for a good but reversible reason to do with colour quality...)
Isn't 59.363 hz too low?
Just seeing that number now I'm almost fully convinced that's what's causing the issue, it's more than half a frame less, I've never seen any game consoles run at that frequency. It's usually between 59.9 hz - 60.1 hz. I hope that color reason wouldn't be much of a sacrifice to restore the speed
The issue seems to be related to that frequency, I just confirmed while writing this, because I can set RetroArch to display at 59.363, and the audio actually has seemingly almost no hiccup, although the image still does. But, the music sounds noticeably downpitched
it's too big of a difference. I'd like to see what the color sacrifice would be if reversed. Thank you.Statistics: Posted by jayare5 — Sat Apr 20, 2024 9:39 am