public void sample_test()
{
string basePath = NUnit.Framework.TestContext.CurrentContext.TestDirectory;
string pathWhereTheDatasetShouldBeStored = Path.Combine(basePath, "mfcc");
#region doc_example1
// Let's say we would like to analyse an audio sample. To give an example that
// could be reproduced by anyone without having to give a specific sound file
// that would need to have been downloaded by every user trying to run this example,
// we will use obtain an example from the Free Spoken Digits Dataset instead:
var fsdd = new FreeSpokenDigitsDataset(path: pathWhereTheDatasetShouldBeStored);
// Let's obtain one of the audio signals:
Signal a = fsdd.GetSignal(0, "jackson", 10);
int sampleRate = a.SampleRate; // 8000
// Note: if you would like to load a signal from the
// disk, you could use the following method directly:
// Signal a = Signal.FromFile(fileName);
// Create a low-pass filter to keep only frequencies below 100 Hz
var filter = new LowPassFilter(frequency: 100, sampleRate: sampleRate);
// Apply the filter to the signal
Signal result = filter.Apply(a);
// Create a spectrogram for the original
var sourceSpectrum = new Spectrogram(a);
// Create a spectrogram for the filtered signal:
var resultSpectrum = new Spectrogram(result);
// Get the count for a high frequency before and after the low-pass filter:
double before = sourceSpectrum.GetFrequencyCount(windowIndex: 0, frequency: 1000); // 0.00028203820434203334
double after = resultSpectrum.GetFrequencyCount(windowIndex: 0, frequency: 1000); // 2.9116651158267508E-05
#endregion
Assert.AreEqual(0.00028203820434203334, before, 1e-8);
Assert.AreEqual(2.9116651158267508E-05, after, 1e-8);
}