Meta parameters and Logic X

Audio Plugins
1

I’ve a plugin with about 3000 parameters. Two of them are meta parameters - changing one of them can change the other one, too.

The plugin worked perfectly, but it failed Logic’s AU Validation.

So I’ve defined these two parameters as meta parameters by returning true in bool AudioProcessor::isMetaParameter(int index) for them, and Logic’s AU Validation passed.

But with this, turning a knob that represents one of the parameters takes several seconds in Logic X. With every parameter update that I send to Logic for one of the two meta parameters, Logic calls AudioProcessor::getParameter(int index) for every single of my 3000 parameters. Well, this as such should be fast, too, as I am only returning the value, but it seems that Logic is doing a lot of other stuff too.

Is there anything I am missing? Is there an option to not only define a parameter as meta parameter, but also to tell Logic which other parameter is influenced by this, to speed it up?

2

Yes, I’ve had a similar test project that I wrote to test meta parameters in JUCE and I got the same delay of a few seconds - but it doesn’t seem to be in JUCE’s code very much. I think this could be a Logic Pro fault. I think the best thing you can do is take Apple’s AudioUnit example project and create 3000 parameters with two meta parameters and see if you can reproduce this. If yes - file a bug with Apple. :smirk: