apd echo

addEcho('input.wav', 'output_with_echo.wav', 2000);

function addEcho(inputWavefile, outputWavefile, circularBuffSize)
    % Read the input wavefile
    [inputSignal, sampleRate] = audioread(inputWavefile);

    % Initialize circular buffer and index
    circularBuffer = zeros(circularBuffSize, size(inputSignal, 2));
    bufferIndex = uint32(1);

    % Initialize delay parameters (adjust as needed)
    feedback = 0.5;      % Adjust the feedback factor (between 0 and 1)

    % Create an output signal with the same size as the input signal
    outputSignal = zeros(size(inputSignal));

    % Apply the echo effect for each channel
    for i = 1:size(inputSignal, 2)
        for j = 1:length(inputSignal)
            % Get the delayed sample from the circular buffer
            delayedSample = circularBuffer(bufferIndex, i);

            % Add the delayed sample to the output signal
            outputSignal(j, i) = inputSignal(j, i) + feedback * delayedSample;

            % Update the circular buffer with the current sample
            circularBuffer(bufferIndex, i) = inputSignal(j, i);

            % Increment the circular buffer index
            bufferIndex = bufferIndex + 1;

            % Wrap around the circular buffer index
            if bufferIndex > circularBuffSize
                bufferIndex = uint32(1);
            end
        end
    end

    % Normalize the output signal to prevent clipping
    maxAmplitude = max(abs(outputSignal(:)));
    if maxAmplitude > 1
        outputSignal = outputSignal / maxAmplitude;
    end

    % Write the output to a wavefile
    audiowrite(outputWavefile, outputSignal, sampleRate);

    % Plot the input and output signals
    figure;
    subplot(2, 1, 1);
    plot(inputSignal);
    title('Input Waveform');
    subplot(2, 1, 2);
    plot(outputSignal);
    title('Output Waveform');
end