Number of channels in the buffer, sidechain, VST3, JUCE 7

Hi, I’ve been working a copule of month ago in a plugin with gen~ and JUCE 6, It has busses properties stereo in/out + stereo sidechain bus for AU and VST3, and mono sidechain bus for AAX. I’m using Reaper in debug mode for AU and VST3 and it seems apparently to work fine at compile and runtime, also AAX looks good in PT (appart from I can’t attach it to Xcode).

Now I’m trying the same code with JUCE 7 (and lastest v6 master branch commit); AU and AAX works fine, but with VST3 something different is happening related to the total number of channels that appears in the buffer, the strange thing is that If I run it with an already opened Reaper project with the plugin already inserted the number of channels of the buffer seems to be ok: 4 (2 main + 2 sc), but when opening a new instance of the plugin it shows only 2 channels (main) in the buffer, also I hit some jassert related to the number of channels in getRMSLevel for the SC meters…

If I go back and run with the previous (april or so) version of JUCE 6 everything works again, and the total number of channels in the buffer is always 4.

Any idea? thank you.

Already running instance in a regular stereo channel in Reaper, JUCE 6/7:

Loading a new instance in a regular stereo channel in Reaper, JUCE 7

Hi @naima,
I think this is related to that change:

(I am not sure of the changes that need to be made on the plugin side though…)

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Oh thank you!! this seems to be, will look into it :wink:

Since upgrading to JUCE 7 I’m hitting this assert. My channel config is set to {0,1}

jassert (arr.inputBuses. size() == getBusCount (true) && arr.outputBuses.size() == getBusCount (false));

I did some test and it seems to me that other VST3 plugins with ext sidechain inputs shows a similar behavior than my plugin in Reaper: in order to use the sidechain inputs I’ve either to specify additional “track channels” or refresh the “VST3 bus size” (wich defaults to auto). So if possible how can I request to Reaper the “VST3 bus size” of 4 when loading the plugin?

vst3. bus size

track ch