Audio VST Plugin UI Control Updates

I'm looking to generate a VST plugin in Matlab and have a use case intended to update the slider UI. Rather than the user controlling the slider, the slider levels are updated regularly based off of internal plugin state. When I try to validate an example plugin, I get the following:

Running testbench...

Error using testbench_pluginname>checkForTampering

Running plugin changed parameter 'XX' from 0 to 0.1.

Error in testbench_pluginname (line 95)

checkForTampering(plugin, paramState, sampleRate, 'Running plugin');

Error in validateAudioPlugin

I am having trouble finding documentation checkForTampering(). Is this more of a warning or hard limit to the Audio System Toolbox's capabilities? I do understand in most use cases you would not want the UI updating itself, however, my project is looking for this exact functionality. Please let me know if there is a better way to update slider UI internally from the plugin itself.

[David]

Additionally, the updated slider is connected to audio processing within the plugin. As an example, it could be a volume level being updated internally and the gain level visualized via vertical slider.

Answer 1

[jibrahim]

Hi David,

This is indeed a limitation of authoring audio plugins in MATLAB: A parameter's value may not be modified by setting another parameter or in the process method of the plugin.

You can certainly have properties in your plugin that depend on the values of one of more plugin parameters, but they may not be plugin parameters.

[David]

Understood. Thank you very much for the quick response! If this functionality become available in a future release, I'd love to use it. I am indeed looking for a plugin parameter that updates the audio processing and UI without having to create separate controls