private void UpdateSpectrumAndCepstrum()
{
var fftSize = int.Parse(fftSizeTextBox.Text);
var cepstrumSize = int.Parse(cepstrumSizeTextBox.Text);
_hopSize = int.Parse(hopSizeTextBox.Text);
if (fftSize != _fftSize)
{
_fftSize = fftSize;
_fft = new RealFft(fftSize);
_cepstralTransform = new CepstralTransform(cepstrumSize, _fftSize);
}
if (cepstrumSize != _cepstrumSize)
{
_cepstrumSize = cepstrumSize;
_cepstralTransform = new CepstralTransform(_cepstrumSize, _fftSize);
}
var pos = _hopSize * _specNo;
var block = _signal[pos, pos + _fftSize];
//block.ApplyWindow(WindowTypes.Hamming);
var cepstrum = new float[_fftSize];
_cepstralTransform.RealCepstrum(block.Samples, cepstrum);
// ************************************************************************
// just visualize spectrum estimated from cepstral coefficients:
// ************************************************************************
var real = new float[_fftSize];
var imag = new float[_fftSize];
for (var i = 0; i < 32; i++)
{
real[i] = cepstrum[i];
}
_fft.Direct(real, real, imag);
var spectrum = _fft.PowerSpectrum(block, normalize: false).Samples;
var avg = spectrum.Average(s => LevelScale.ToDecibel(s));
var spectrumEstimate = real.Take(_fftSize / 2 + 1)
.Select(s => (float)LevelScale.FromDecibel(s * 40 - avg))
.ToArray();
spectrumPanel.Line = spectrum;
spectrumPanel.Markline = spectrumEstimate;
spectrumPanel.ToDecibel();
var pitch = Pitch.FromCepstrum(block);
cepstrumPanel.Line = cepstrum;
cepstrumPanel.Mark = (int)(_signal.SamplingRate / pitch);
}
// Update chart of frequency domain
private void UpdateSpectra()
{
var fftSize = int.Parse(fftSizeTextBox.Text);
var cepstrumSize = int.Parse(cepstrumSizeTextBox.Text);
_hopSize = int.Parse(hopSizeTextBox.Text);
if (fftSize != _fftSize)
{
_fftSize = fftSize;
_fft = new Fft(fftSize);
_cepstralTransform = new CepstralTransform(cepstrumSize, _fftSize);
}
if (cepstrumSize != _cepstrumSize)
{
_cepstrumSize = cepstrumSize;
_cepstralTransform = new CepstralTransform(_cepstrumSize, _fftSize);
}
var pos = _hopSize * _specNo;
var block = _signal[pos, pos + _fftSize];
block.ApplyWindow(WindowTypes.Hamming);
var cepstrum = _cepstralTransform.Direct(block);
var real = new float[_fftSize];
var imag = new float[_fftSize];
for (var i = 0; i < 32; i++)
{
real[i] = cepstrum[i];
}
_fft.Direct(real, imag);
var spectrum = _fft.PowerSpectrum(block, normalize: false).Samples;
var avg = spectrum.Average(s => LevelScale.ToDecibel(s));
var spectrumEstimate = real.Take(_fftSize / 2 + 1)
.Select(s => (float)LevelScale.FromDecibel(s * 40 / _fftSize - avg))
.ToArray();
spectrumPanel.Line = spectrum;
spectrumPanel.Markline = spectrumEstimate;
spectrumPanel.ToDecibel();
spectrumPanel.max_freq_value = spectrum.Length * _signal.SamplingRate / fftSize;
}
public void TestInverseComplexCepstrum()
{
var ct = new CepstralTransform(8);
var input = new[] { 1, 7, 2, 100, 59, 32, 11, 72f };
var output = new float[8];
var cepstrum = new float[8];
var d = ct.Direct(input, output);
ct.Inverse(output, cepstrum, d);
Assert.That(cepstrum, Is.EqualTo(input).Within(1e-4));
}
private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
var ofd = new OpenFileDialog();
if (ofd.ShowDialog() != DialogResult.OK)
{
return;
}
using (var stream = new FileStream(ofd.FileName, FileMode.Open))
{
var waveFile = new WaveFile(stream);
_signal = waveFile[Channels.Left];
}
_fftSize = int.Parse(fftSizeTextBox.Text);
_cepstrumSize = int.Parse(cepstrumSizeTextBox.Text);
_hopSize = int.Parse(hopSizeTextBox.Text);
_fft = new RealFft(_fftSize);
_cepstralTransform = new CepstralTransform(_cepstrumSize, _fftSize);
var options = new PitchOptions
{
SamplingRate = _signal.SamplingRate,
FrameDuration = (double)_fftSize / _signal.SamplingRate,
HopDuration = (double)_hopSize / _signal.SamplingRate
};
var pitchExtractor = new PitchExtractor(options);
_pitches = pitchExtractor.ParallelComputeFrom(_signal);
_specNo = 0;
specNoComboBox.DataSource = Enumerable.Range(1, _pitches.Count).ToArray();
// obtain spectrogram
_stft = new Stft(_fftSize, _hopSize, WindowTypes.Rectangular);
var spectrogram = _stft.Spectrogram(_signal);
spectrogramPanel.ColorMapName = "viridis";
spectrogramPanel.MarklineThickness = 6;
spectrogramPanel.Spectrogram = spectrogram.Select(s => s.Take(224).ToArray()).ToList();
spectrogramPanel.Markline = _pitches.Select(p => p[0] * _fftSize / _signal.SamplingRate).ToArray();
}
/// <summary>
/// Pitch estimation from signal cepstrum
/// </summary>
/// <param name="signal"></param>
/// <param name="startPos"></param>
/// <param name="endPos"></param>
/// <param name="low"></param>
/// <param name="high"></param>
/// <param name="cepstrumSize"></param>
/// <param name="fftSize"></param>
/// <returns></returns>
public static float FromCepstrum(DiscreteSignal signal,
int startPos = 0,
int endPos = -1,
float low = 80,
float high = 400,
int cepstrumSize = 256,
int fftSize = 1024)
{
var samplingRate = signal.SamplingRate;
if (endPos == -1)
{
endPos = signal.Length;
}
if (startPos != 0 || endPos != signal.Length)
{
signal = signal[startPos, endPos];
}
var pitch1 = (int)(1.0 * samplingRate / high); // 2,5 ms = 400Hz
var pitch2 = Math.Min(cepstrumSize - 1, (int)(1.0 * samplingRate / low)); // 12,5 ms = 80Hz
var cepstrum = new float[cepstrumSize];
var cepstralTransform = new CepstralTransform(cepstrumSize, fftSize);
cepstralTransform.RealCepstrum(signal.Samples, cepstrum);
var max = cepstrum[pitch1];
var peakIndex = pitch1;
for (var k = pitch1 + 1; k <= pitch2; k++)
{
if (cepstrum[k] > max)
{
max = cepstrum[k];
peakIndex = k;
}
}
return((float)samplingRate / peakIndex);
}
private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
var ofd = new OpenFileDialog();
if (ofd.ShowDialog() != DialogResult.OK)
{
return;
}
using (var stream = new FileStream(ofd.FileName, FileMode.Open))
{
var waveFile = new WaveFile(stream);
_signal = waveFile[Channels.Left];
}
_fftSize = int.Parse(fftSizeTextBox.Text);
_cepstrumSize = int.Parse(cepstrumSizeTextBox.Text);
_hopSize = int.Parse(hopSizeTextBox.Text);
_fft = new Fft(_fftSize);
_cepstralTransform = new CepstralTransform(_cepstrumSize, _fftSize);
var pitchTracker = new Pitch((float)_fftSize / _signal.SamplingRate,
(float)_hopSize / _signal.SamplingRate);
_pitchTrack = pitchTracker.Track(_signal);
UpdateSpectra();
UpdateAutoCorrelation();
// obtain spectrogram
_stft = new Stft(_fftSize, _hopSize, WindowTypes.Rectangular);
var spectrogram = _stft.Spectrogram(_signal);
spectrogramPanel.ColorMapName = "viridis";
spectrogramPanel.Spectrogram = spectrogram.Select(s => s.Take(224).ToArray()).ToList();
spectrogramPanel.Markline = _pitchTrack.Select(p => p * _fftSize / _signal.SamplingRate).ToArray();
specNoComboBox.DataSource = Enumerable.Range(1, _pitchTrack.Count).ToArray();
_specNo = 0;
}
// Open file
private void openToolStripMenuItem_Click(object sender, EventArgs e)
{
spectrumPanel.refresh();
signalPanel.refresh();
signalPanel.Stride = 64;
var ofd = new OpenFileDialog();
if (ofd.ShowDialog() != DialogResult.OK)
{
return;
}
txtFilePath.Text = ofd.FileName;
_waveFileName = ofd.FileName;
try
{
using (var stream = new FileStream(_waveFileName, FileMode.Open))
{
IAudioContainer waveFile = new WaveFile(stream);
_signal = waveFile[Channels.Left];
_signal_storage = _signal;
}
}
catch (IOException ex)
{
Console.WriteLine("Error reading from {0}. Message = {1}", _waveFileName, ex.Message);
}
// Get duration
WaveFileReader wf = new WaveFileReader(_waveFileName);
var totalTime = wf.TotalTime;
txtTotalTime.Text = totalTime.TotalMilliseconds.ToString() + " ms";
signalPanel.max_time_value = (float)totalTime.TotalMilliseconds;
var max_value = _signal[0];
var count = 0;
for (int i = 1; i < _signal.Length; i++)
{
if (max_value < _signal[i])
{
max_value = _signal[i];
}
if (_signal[i] > 0.2)
{
count++;
}
}
txtMaxValue.Text = max_value.ToString();
signalPanel.Signal = _signal;
_fftSize = int.Parse(fftSizeTextBox.Text);
_cepstrumSize = int.Parse(cepstrumSizeTextBox.Text);
_hopSize = int.Parse(hopSizeTextBox.Text);
_fft = new Fft(_fftSize);
_cepstralTransform = new CepstralTransform(_cepstrumSize, _fftSize);
var pitchTracker = new Pitch((float)_fftSize / _signal.SamplingRate,
(float)_hopSize / _signal.SamplingRate);
_pitchTrack = pitchTracker.Track(_signal);
// Show chart in frequency domain
UpdateAutoCorrelation();
UpdateSpectra();
// obtain spectrogram
_stft = new Stft(_fftSize, _hopSize, WindowTypes.Rectangular);
var spectrogram = _stft.Spectrogram(_signal);
specNoComboBox.DataSource = Enumerable.Range(1, _pitchTrack.Count).ToArray();
_specNo = 0;
spectrumPanelAfterFilter.refresh();
signalPanelAfterFilter.refresh();
lblNote.Visible = false;
savePWMDataToolStripMenuItem.Enabled = true;
}
