Bug: VST2 host frame count not monotonic

dromer · 06-25-2022, 06:30 PM

Same bug as VST2/3 on BitWig.

Due to suspected rounding errors the early frame-count is sometimes +/-1 off.

Relevant code:
https://github.com/DISTRHO/DPF/commi...9dbc5fec12a882
https://github.com/DISTRHO/Cardinal/...e1bb00e17df340

Problem does not occur with VST3 and LV2.

Justin · 06-25-2022, 06:48 PM

Hmm if you use floor(VstTimeInfo::samplePos+0.5) it should be monotonic. I suppose we should be doing that rounding on our end.

dromer · 06-26-2022, 03:14 AM

Quote:

Originally Posted by Justin

Hmm if you use floor(VstTimeInfo::samplePos+0.5) it should be monotonic. I suppose we should be doing that rounding on our end.

Yes, this should really be handled host side. It's the actual number of frames sent to the plugin that is inconsistent.
In VST3 and LV2 implementations this works correctly.

06-25-2022, 06:30 PM	#1
dromer Human being with feelings Join Date: Dec 2021 Location: The Netherlands Posts: 13	Bug: VST2 host frame count not monotonic Same bug as VST2/3 on BitWig. Due to suspected rounding errors the early frame-count is sometimes +/-1 off. Relevant code: https://github.com/DISTRHO/DPF/commi...9dbc5fec12a882 https://github.com/DISTRHO/Cardinal/...e1bb00e17df340 Problem does not occur with VST3 and LV2.

06-25-2022, 06:48 PM	#2
Justin Administrator Join Date: Jan 2005 Location: NYC Posts: 16,783	Hmm if you use floor(VstTimeInfo::samplePos+0.5) it should be monotonic. I suppose we should be doing that rounding on our end.