ValidateAudioPlugin Error "Input series must be a numeric vector" in plugin

I am working on a plugin that takes in two channels. For some reason the validation is failing and I don't understand why. With other two-channel plugins I found online it works alright. What does it mean that "input series must be a numeric vector"? How do I fix it?

Here is the code:

classdef myVocoder < audioPlugin
    properties (Access = private)
        p = 12; % LPC Filter Order
    end
    properties (Constant)
        PluginInterface = audioPluginInterface( ...
            'PluginName','Vocoder', ...
            'InputChannels',[2 2], ...
            'OutputChannels',2);
    end
    methods
        function out = process(plugin, in1, in2)
            % LPC
            r2 = autocorr(in1, plugin.p);    % LPCs coefficients for last two frames
            coeffs = levinson(r2, plugin.p);        % Solve with Levinson Durbin   

            vocoder_curr = (filter(1, coeffs, in2)); % Filter glottal pulses with LPC Filter
            vocoder_play = vocoder_curr;
            
            % AGC: if voice in is louder, voice out should be louder too
            gain = std(in1)/std(vocoder_curr);

            out = gain*vocoder_play;
        end                                                  
    end
end

Answer 1

[jibrahim]

Hi Pedro,

This error is thrown from the first line of your process method. To reproduce:

v = myVocoder
process(plugin,randn(2,2),randn(2,2))

Essentially this line is failing:

r2 = autocorr(randn(2,2), 12)

In general, in order to debug issues caught by validateAudioPlugin, you can do the following:

validateAudioPlugin -keeptestbench myVocoder

This will keep the MATLAB testbench code for you. Then, you can run the testbwench file, and put a debug point where it fails:

testbench_myVocoder