public void Test_SFF_Mel()
{
(double[] audio, int sampleRate) = AudioFile.ReadWAV("../../../../../data/cant-do-that-44100.wav");
int fftSize = 1 << 12;
var spec = new SpectrogramGenerator(sampleRate, fftSize, stepSize: 700);
var window = new FftSharp.Windows.Hanning();
spec.SetWindow(window.Create(fftSize / 3)); // sharper window than typical
spec.Add(audio);
Bitmap bmp = spec.GetBitmapMel(250);
bmp.Save("../../../../../dev/sff/halMel.png", System.Drawing.Imaging.ImageFormat.Png);
spec.SaveData("../../../../../dev/sff/halMel.sff", melBinCount: 250);
var spec2 = new SFF("../../../../../dev/sff/halMel.sff");
Assert.AreEqual(spec.SampleRate, spec2.SampleRate);
Assert.AreEqual(spec.StepSize, spec2.StepSize);
Assert.AreEqual(spec.Width, spec2.Width);
Assert.AreEqual(spec.FftSize, spec2.FftSize);
Assert.AreEqual(spec.NextColumnIndex, spec2.FftFirstIndex);
Assert.AreEqual(spec.Height, spec2.Height);
Assert.AreEqual(spec.OffsetHz, spec2.OffsetHz);
}
private double[] SubtractMovingWindow(double[] input, int windowSizePx = 100)
{
// return a copy of the input array with the moving window subtracted
var hanningWindow = new FftSharp.Windows.Hanning();
double[] window = hanningWindow.Create(windowSizePx);
double windowSum = window.Sum();
double[] windowed = new double[input.Length];
double[] normalized = new double[input.Length];
for (int i = 0; i < input.Length - window.Length; i++)
{
double windowedInputSum = 0;
for (int j = 0; j < window.Length; j++)
{
windowedInputSum += input[i + j] * window[j];
}
windowed[i + window.Length / 2] = windowedInputSum / windowSum;
}
for (int i = 0; i < input.Length; i++)
{
normalized[i] = Math.Max(input[i] - windowed[i], 0);
}
return(normalized);
}
public Settings(int sampleRate, int fftSize, int stepSize, double minFreq, double maxFreq, int offsetHz)
{
if (FftSharp.Transform.IsPowerOfTwo(fftSize) == false)
{
throw new ArgumentException("FFT size must be a power of 2");
}
// FFT info
SampleRate = sampleRate;
FftSize = fftSize;
StepSize = stepSize;
FftLengthSec = (double)fftSize / sampleRate;
// vertical
minFreq = Math.Max(minFreq, 0);
FreqNyquist = sampleRate / 2;
HzPerPixel = (double)sampleRate / fftSize;
PxPerHz = (double)fftSize / sampleRate;
FftIndex1 = (minFreq == 0) ? 0 : (int)(minFreq / HzPerPixel);
FftIndex2 = (maxFreq >= FreqNyquist) ? fftSize / 2 : (int)(maxFreq / HzPerPixel);
Height = FftIndex2 - FftIndex1;
FreqMin = FftIndex1 * HzPerPixel;
FreqMax = FftIndex2 * HzPerPixel;
FreqSpan = FreqMax - FreqMin;
OffsetHz = offsetHz;
// horizontal
StepLengthSec = (double)StepSize / sampleRate;
var window = new FftSharp.Windows.Hanning();
Window = window.Create(fftSize);
StepOverlapSec = FftLengthSec - StepLengthSec;
StepOverlapFrac = StepOverlapSec / FftLengthSec;
}
public void Test_SFF_Linear()
{
(double[] audio, int sampleRate) = AudioFile.ReadWAV("../../../../../data/cant-do-that-44100.wav");
int fftSize = 1 << 12;
var spec = new SpectrogramGenerator(sampleRate, fftSize, stepSize: 700, maxFreq: 2000);
var window = new FftSharp.Windows.Hanning();
spec.SetWindow(window.Create(fftSize / 3)); // sharper window than typical
spec.Add(audio);
spec.SaveData("../../../../../dev/sff/hal.sff");
var spec2 = new SFF("../../../../../dev/sff/hal.sff");
Assert.AreEqual(spec.SampleRate, spec2.SampleRate);
Assert.AreEqual(spec.StepSize, spec2.StepSize);
Assert.AreEqual(spec.Width, spec2.Width);
Assert.AreEqual(spec.FftSize, spec2.FftSize);
Assert.AreEqual(spec.NextColumnIndex, spec2.FftFirstIndex);
Assert.AreEqual(spec.Height, spec2.Height);
Assert.AreEqual(spec.OffsetHz, spec2.OffsetHz);
}
public void Test_Make_CommonColormaps()
{
(double[] audio, int sampleRate) = AudioFile.ReadWAV("../../../../../data/cant-do-that-44100.wav");
int fftSize = 1 << 12;
var spec = new SpectrogramGenerator(sampleRate, fftSize, stepSize: 700, maxFreq: 2000);
var window = new FftSharp.Windows.Hanning();
spec.SetWindow(window.Create(fftSize / 3)); // sharper window than typical
spec.Add(audio);
// delete old colormap files
foreach (var filePath in System.IO.Directory.GetFiles("../../../../../dev/graphics/", "hal-*.png"))
{
System.IO.File.Delete(filePath);
}
foreach (var cmap in Colormap.GetColormaps())
{
spec.Colormap = cmap;
spec.SaveImage($"../../../../../dev/graphics/hal-{cmap.Name}.png");
Debug.WriteLine($"");
}
}
