private void ProcessFullSpectrum()
{
//Prepare audio samples
float[] preProcessedSamples = new float[totalSamples];
int numProcessed = 0;
float combinedChannelAverage = 0f;
//Combine channels if the audio is stereo
//Add to pre-processed array to be passed through the fft
for (int i = 0; i < multiChannelSamples.Length; i++)
{
combinedChannelAverage += multiChannelSamples[i];
//Store the average of the channels combined for a single time index
if ((i + 1) % this.numberOfChannels == 0)
{
preProcessedSamples[numProcessed] = combinedChannelAverage / numberOfChannels;
numProcessed++;
combinedChannelAverage = 0f;
}
}
//Execute an FFT to return the spectrum data over the time domain
int totalIterations = preProcessedSamples.Length / spectrumSampleSize;
//Instantiate and initialise a new FFT
FFT fft = new FFT();
fft.Initialize((uint)spectrumSampleSize);
double[] sampleChunk = new double[spectrumSampleSize];
for (int i = 0; i < totalIterations; i++)
{
//Get the current chunk of audio sample data
Array.Copy(preProcessedSamples, i * spectrumSampleSize, sampleChunk, 0, spectrumSampleSize);
//Apply an FFT Window type to the input data and calculate a scale factor
double[] windowCoefficients = DSP.Window.Coefficients(DSP.Window.Type.Hanning, (uint)spectrumSampleSize);
double[] scaledSpectrumChunk = DSP.Math.Multiply(sampleChunk, windowCoefficients);
double scaleFactor = DSP.Window.ScaleFactor.Signal(windowCoefficients);
//Execute the FFT and get the scaled spectrum back
Complex[] fftSpectrum = fft.Execute(scaledSpectrumChunk);
//Convert the complex spectrum into a usable format of doubles
double[] scaledFFTSpectrum = DSP.ConvertComplex.ToMagnitude(fftSpectrum);
//Apply the window scale to the spectrum
scaledFFTSpectrum = DSP.Math.Multiply(scaledFFTSpectrum, scaleFactor);
//The magnitude values correspond to a single point in time
float currentSongTime = GetTimeFromIndex(i) * spectrumSampleSize;
//Send magnitude spectrum data to Spectral Flux Analyzer to be analyzed for peaks
analyzer.AnalyzeSpectrum(Array.ConvertAll(scaledFFTSpectrum, x => (float)x), currentSongTime);
}
Debug.Log("Spectrum Analysis done");
}
private void AnalyzeFullSpectrum()
{
try
{
//We only retain the samples of combined channel over the time domain
float[] processedSamples = new float[totalNumberOfSamples];
int numProcessed = 0;
float channelAverage = 0f;
for (int i = 0; i < multiChannelSamples.Length; ++i)
{
channelAverage += multiChannelSamples[i];
//Store the average of the combined channels
if ((i + 1) % numberOfChannels == 0)
{
processedSamples[numProcessed] = channelAverage / numberOfChannels;
++numProcessed;
channelAverage = 0f;
}
}
//Debug.Log("Channel combining done. Total number of samples processed: " + processedSamples.Length);
//Execute Fast-Fourier Transform to return the spectrum data over time
int spectrumSampleSize = 1024;
int iterations = processedSamples.Length / spectrumSampleSize;
FFT fft = new FFT();
fft.Initialize((System.UInt32)spectrumSampleSize);
double[] sampleChunk = new double[spectrumSampleSize];
for (int i = 0; i < iterations; ++i)
{
//Grab the current 1024 chunk of audio data
System.Array.Copy(processedSamples, i * spectrumSampleSize, sampleChunk, 0, spectrumSampleSize);
//Apply FFT
double[] windowCoEf = DSP.Window.Coefficients(DSP.Window.Type.Hanning, (uint)spectrumSampleSize);
double[] scaledSampleChunk = DSP.Math.Multiply(sampleChunk, windowCoEf);
double scaleFactor = DSP.Window.ScaleFactor.Signal(windowCoEf);
//Perform FFT and convert output to magnitude
Complex[] fftSpectrum = fft.Execute(scaledSampleChunk);
double[] scaledFFTSpectrum = DSP.ConvertComplex.ToMagnitude(fftSpectrum);
scaledFFTSpectrum = DSP.Math.Multiply(scaledFFTSpectrum, scaleFactor);
//Convert the chunk values to a single point within audio timeline
float currSongtime = GetSongtime(i) * spectrumSampleSize;
//Analyze multitude data using SpectrumAnalyzer to detect peaks
spectrumAnalyzer.AnalyzeSpectrum(System.Array.ConvertAll(scaledFFTSpectrum, x => (float)x), currSongtime);
}
//Debug.Log("Spectrum Analysis completed, now getting all Peak data samples.");
for (float i = 0f; i <= clipLength; i += 0.0167f)
{
//Get the index from the audio time
int index = GetIndex(i) / spectrumAnalyzer.numSamples;
//Only run if index returned is within range of the spectrum analyzer sample-list
if (index < spectrumAnalyzer.spectralFluxSamples.Count)
{
SpectralFluxInfo info = spectrumAnalyzer.spectralFluxSamples[index];
//Make sure sample is a peak
if (info.isPeak)
{
peakInfo.Add(info);
}
}
}
//Debug.Log("Spectrum Analysis and Peak Sampling done. Thread completed.");
peakInfoSize = peakInfo.Count;
isDone = true;
}
catch (System.Exception ex)
{
//Error logging
Debug.LogError(ex.ToString());
}
}