Handle each channel separately

Developer VST 3 SDK
1

I am trying to put up an instrument plugin. I am having issues getting the two stereo channels independently. Since I am looking for stereo output, I initialize the buses in my processor as follows -

addEventInput(STR16(Event In), 1);|
addAudioOutput(STR16(AudioOutput), Vst::SpeakerArr::kStereo);|

Now in the process function, I expect to handle the left and right channels independently .
Like

float* leftOutput = data.outputs[0].channelBuffers32[0];
float* rightOutput = data.outputs[0].channelBuffers32[1];

But I get only one channel

float* finalOutput = data.outputs[0].channelBuffers32[0];|

Incidentally the audio is heard on both speakers.

The moment I try

float* rightOutput = data.outputs[0].channelBuffers32[1];

It throws up build error.

What gives ? How can I get access to channelBuffers32[0] and channelBuffers32[1] independently

2

Which host are you using? Do you have a custom implementation for IAudioProcessor::setBusArrangement(..) or IAudioProcessor::getBusArrangement(..)?

3

I have tried with multiple DAWs.- SDK included TestHost, Reaper and Cakewalk.

I have not set up any specific bus arrangement with setBusArrangement. Am I supposed to do that ?

4

Normally not.
What’s the number in data.outputs[0].numChannels?

5

This shows as 2.

ss
ss946×261 16.9 KB

6

That all looks correct. Something else must be wrong in your code as the host is required to provide valid buffers in the process function (when numSamples > 0).

7

I am not sure what the issue was but setBusArrangements solved the issue.

tresult PLUGIN_API SProcessor::setBusArrangements(Steinberg::Vst::SpeakerArrangement* inputs, int32 numIns, Steinberg::Vst::SpeakerArrangement* outputs, int32 numOuts)
{
// one stereo output bus
if (numIns == 0 && numOuts == 1 && outputs[0] == Vst::SpeakerArr::kStereo)
{
return AudioEffect::setBusArrangements(inputs, numIns, outputs, numOuts);
}
return kResultFalse;
}

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