I made a stereo effect plugin. As VST it comes up in Reaper as (2 in/2 out) which is as expected, but the AU version of the same comes out as (1in/1out) in Reaper… JucePluginHost shows correct (2in/2out) also for the AU.
I figured out its because i have:
#define JucePlugin_MaxNumInputChannels 2
#define JucePlugin_MaxNumOutputChannels 2
#define JucePlugin_PreferredChannelConfigurations {1, 1}, {2, 2}
and reaper choose the {1,1} in case of using an AU, and {2,2} for the VST.
What is the rule here? I want the DAWs to choose Stereo if possible, and Mono as fallback - for example in case of using a mono input audio interface.