realtime_test.m

function realtime_test
%% AUDIO INPUT

% Choose input mode: either 'FILE' or 'DEVICE'
inputMode = 'FILE';
%   Then make sure to check/set the parameters for that input mode
%   in the AUDIO INPUT section.

% Number of samples to process with each loop iteration
% Note: If using ASIO, set output buffer size equal to this.
frameSize = 1024;

if strcmp(inputMode, 'FILE')
    % Input mode 'FILE' : read audio from file
    
    % Parameters
    fileName = 'wonderwall_48k_32bit.flac'; 
    file = strcat('audio_samples/', fileName);
    nPlays = 1; % Number of times to play file
    readRange = [1 inf]; % Range of samples to be read
    
    % Create audio source
    src = dsp.AudioFileReader(file, ...
        'PlayCount', nPlays, ...
        'SamplesPerFrame', frameSize, ...
        'ReadRange', readRange);

elseif strcmp(inputMode, 'DEVICE')
    % Input mode 'DEVICE' : read audio from device
    
    % Parameters
    sampleRate = 48000; % Samples/sec
    inputDriver = 'ASIO'; % N/A for Mac/Linux
    inputDevice = 'Analogue 1 + 2 (Focusrite Usb Audio)'; % List w/ getAudioDevices
    chanMap = 1; % Which channel to use
    
    % Create audio source
    src = audioDeviceReader(sampleRate, ...
        'Driver', inputDriver, ...
        'Device', inputDevice, ...
        'SamplesPerFrame', frameSize, ...
        'ChannelMappingSource', 'Property', ...
        'ChannelMapping', chanMap);
else
    % Input mode not valid/selected
    disp('Please set the input mode to either FILE or DEVICE')
end

%% AUDIO OUTPUT

% Parameters
outputDriver = 'ASIO'; % N/A for Mac/Linux
outputDevice = 'Focusrite USB ASIO'; % List w/ getAudioDevices
buffSize = frameSize; % Buffer size, must = frame size for ASIO

% Create audio sink
snk = audioDeviceWriter(...
    'Driver', outputDriver, ...
    'Device', outputDevice, ...
    'SampleRate', src.SampleRate, ...
    'SupportVariableSizeInput', true, ...
    'BufferSize', buffSize);

% This might be all that's needed for built-in soundcards:
% snk = audioDeviceWriter(src.SampleRate);

%% SCOPES + VISUALIZATION

% Oscilloscope
scope = timescope(...
    'SampleRate', src.SampleRate, ...
    'BufferLength', src.SampleRate*4, ...
    'YLimits', [-1, 1]);

% Spectrum Analyzer
spectrum = dsp.SpectrumAnalyzer(...
    'NumInputPorts', 1, ...
    'SpectrumType', 'Power', ...
    'ViewType', 'Spectrum', ...
    'SampleRate', src.SampleRate, ...
    'PlotAsTwoSidedSpectrum', false, ...
    'FrequencyScale', 'Log');

% Spectrogram
spectrogram = dsp.SpectrumAnalyzer(...
    'NumInputPorts', 1, ...
    'SpectrumType', 'Power', ...
    'ViewType', 'Spectrogram', ...
    'SampleRate', src.SampleRate, ...
    'PlotAsTwoSidedSpectrum', false, ...
    'FrequencyScale', 'Log');
    

%% FX BLOCKS

% Reverb (from example)
reverb = reverberator(...
    'SampleRate', src.SampleRate, ...
    'PreDelay', 0, ...
    'WetDryMix', 0.4);

%% AUDIO STREAM LOOP

loopTime = 15; % (seconds), Used only for DEVICE mode

if strcmp(inputMode, 'FILE')
    while ~isDone(src)
        swag()
    end
elseif strcmp(inputMode, 'DEVICE')
    disp(strcat('Begin signal input... (', inputDevice, ...
        ", CH. ", num2str(chanMap), ')'))
    tic
    while toc < loopTime
        swag()
    end
    disp('End signal input.')
end

%% RELEASE OBJECTS

release(src)
release(snk)
release(reverb)
release(scope)
release(spectrum)
release(spectrogram)

%% SPECTRAL WAVETABLE ANALOG/GUITAR ALGORITHM

    function swag()
        inputAudio = src();
        
        % Algorithm goes here
        %outputAudio = ammod(inputAudio, 300, src.SampleRate);
        outputAudio = reverb(inputAudio);
        
        snk(outputAudio);
        
        % Optional visualization
        
        % scope(mean(inputAudio, 2))
        % scope(mean(outputAudio, 2))
        % scope([mean(inputAudio, 2), mean(outputAudio, 2)])
        
        % spectrum(mean(inputAudio, 2))
        % spectrum(mean(outputAudio, 2))
        % spectrum([mean(inputAudio, 2), mean(outputAudio, 2)])
        
        % spectrogram(mean(inputAudio, 2))
        spectrogram(mean(outputAudio, 2))
    end

end