Configuration of channel layout of vst2

Although I set Plugin Channel Configuration as {0, 2}, vst2 shows the both Mono and Stereo at Channel Layout on Configure Audio IO in context menu of the filter in AudioPluginHost.

Other plugin types shows Stereo only. I assume this is the bug of juce tho, can I have any workarounds of this?

Documentation is quite difficult to find on this topic, so it’s possible I’ve missed something. However, I’m fairly sure that the behaviour you’re seeing is a limitation of the VST2 format.

As far as I can tell, these layouts are only advisory for VST plugins. The host will check the maximum number of supported channels, but may opt to send fewer channels to the plugin during processing.

Other plugin formats have more fine-grained control over allowed channel configurations, which is why you see the expected results for AU/VST3 plugins.

I’d recommend checking the total number of ins/outs during processing and making sure only to process channels that are currently in use.