Unload VST3 modules after removing plugins

Hello. I’m using Ardour 7.2 on Linux UbuntuStudio 22.10

I learned that Ardour keeps VST3 modules in memory even after removing plug-ins from the channel strip.

Is there a way (preferences, a script, a command line option) to change that behavior so that modules are unloaded after removing the plugins?

How did you learn that?

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Removing the last instance of a given plugin closes the shared object

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README.MD file on Yabridge Github repository. It reads:

  • Some hosts, particularly Ardour, REAPER, Qtractor, will by default not unload VST3 modules after you close the last plugin. This means that the associated yabridge-host.exe process will keep running until you close the project. For REAPER there’s an option called Allow complete unload of VST plug-ins in the VST tab of the settings dialog to disable this behavior.

I’m having problems with Waves VST3 plugins with Yabridge. Once you put them on the track or the bus, they work fine, but you can no longer remove them (the DAW freezes if you try). This issue also occurs when you exit the DAW. It completely freezes.
The problem doesn’t happen with the corresponding VST2 plugins. I could disable the concealing option, but I don’t want to, because my plugins list is already too big.
So I was trying to find an option to unload the plugins from memory after closing them to see if that solves (or workarounds) the problem.
But as you pointed out: Ardour already unload it by default.

This problem didn’t happen until some time ago (I hate myself for not noticing which Yabridge or Wine version I upgraded to when the problem started to crop up). Let’s see if, in the next releases, this will be resolved.

Thank you for your answer.

Robin will understand the specifics of that implementation better, but using a bridge to load Windows plugins is not really the same as loading a native VST plugin into Ardour. In the case of a bridge, the plugin is never really instantiated directly by Ardour, there is some kind of wrapper which is what Ardour interacts with, so you would likely have to remove all Windows native plugins from all tracks before the yabridge plugin wrapper would be removed.

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I see this on the recent 5.0.4 release of yabridge

Fixed a regression from yabridge 4.0.0 where plugin groups would not exit correctly. When removing a plugin instance that was part of a plugin group, it would block until the group host process had exited. This in turn resulted in hangs if the group host process hosted more than one plugin instance.

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I’ve made some tests and you’re right.
Actually, the Yabridge CPU processes stay there until you close the DAW.
Same thing happens in both Ardour and Tracktion Waveform.
The difference is that you can remove Waves plugins in Waveform and close the DAW with no trouble.
On the other hand that happens on Ardour with Waves plugins only.

But, anyway, I didn’t want to bore you, guys, with those issues. I chose the “How do I…” category because I wanted to know if there was a way to unload modules after removing VST3 plugins, so I could try to troubleshoot this. But Robin already explained they already are unloaded.

Thank you very much for your answer.

It’s true.
But unfortunately, I’ve already updated to 5.0.4 version and the problem is still here.
I don’t even know if it’s a bug or if it’s something exclusively with my system.

I’ll keep testing.
Interesting: on Yabridge RELEASE.md there is also this:
" * Waves V13 VST3 plugins have memory issues, at least under Wine. They will likely randomly crash at some point. If you can avoid Waves, that would be for the best. Otherwise, try the V12 versions of the plugins if you still have a license for them."

My plugins are v14. In my case it’s not a “crash”. It’s freezing the DAW.

Thank you for your reply.