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); }