VST Effect's parameter reset when clicking Play

Hello everyone.

Five month ago, I submitted an issue describing to me what is a game-breaking bug, and although we’re many experiencing this problem, it still have not been addressed… thus, I allow myself to talk about it here, hoping to attract more developers and contributors to this issue.

Basically, it’s about realtime VST (2 & 3) plugins, when I click “Play” to resume realtime audio processing, all the parameters in my VST plugin window are visibly reset, as well as audibly.

The easiest way to reproduce for me is with the free plugin Thimeo Stereo Tools 9.92 VST2 (I’m on Windows by the way). The parameters are reset every single time I hit “Play”.

In the current state, I cannot use Audacity anymore… would someone please, investigate on this issue?

Thank you very much in advance.

Possible workaround: save parameters as a preset within the plugin, (no guarantee).

Tested, it seems to work, but annoying as hell…

Sorry to bump this, but is it possible to get an update to this issue?

I tried to lookup in the code myself, but I couldn’t find the cause… may I get some help to fix this bug once and for all?

The individual code bits happen in

  • libraries/lib-vst (and lib-vst3/lib-lv2/…) for VST specific code
  • libraries/lib-effects for general effects code
  • libraries/lib-realtime-effects for realtime effects code

As a shot in the dark, lib-realtime-effects/RealtimeEffectState.cpp sounds like a place to set some breakpoints in to debug this.


Last time I dug, I eliminated lib-realtime-effects for the cause of the bug, I think it lies in lib-vst and lib-vst3