private static Dictionary <string, double[]> loadKeywordHistograms()
{
var result = new Dictionary <string, double[]>();
foreach (var keywordFilename in Directory.EnumerateFiles(Directory.GetCurrentDirectory(), "*.wav", SearchOption.TopDirectoryOnly))
{
var wavFile = new WavFile(keywordFilename);
if (wavFile.ReadMono16bit(out short[] samples))
{
string keyword = Path.GetFileNameWithoutExtension(keywordFilename);
result[keyword] = calculateFFT(samples);
}
}
return(result);
}
static async Task Main(string[] args)
{
// =============================================================================================================
// inspired by: https://stackoverflow.com/questions/4087727/openal-how-to-create-simple-microphone-echo-programm
string captureDeviceSpecifier = Alc.GetString(IntPtr.Zero, Alc.CaptureDeviceSpecifier);
Console.WriteLine("Capture device name: " + captureDeviceSpecifier);
//var audioDevice = Alc.OpenDevice(null);
////var errorCode = Alc.GetError(audioDevice); // TODO: check this after each Alc call
////var errorCode = Al.GetError(); // TODO: check this after each Al call
//var context = Alc.CreateContext(audioDevice, null);
//Alc.MakeContextCurrent(context);
const int frequency = 44100;
const int keywordLength = (int)(frequency);
var captureDevice = Alc.CaptureOpenDevice(captureDeviceSpecifier, frequency, format: Al.FormatMono16, buffersize: frequency);
string deviceName = Alc.GetString(captureDevice, Alc.DeviceSpecifier);
Console.WriteLine($"{deviceName} is open for capture.");
if (args.Length > 0 && args[0] == "record")
{
while (true)
{
Console.Write("Enter keyword name: ");
string keywordName = Console.ReadLine();
if (string.IsNullOrWhiteSpace(keywordName)) // exit if nothing entered
{
break;
}
Alc.CaptureStart(captureDevice);
Console.WriteLine("recording keyword..."); // need new line for intensity visualization
short[] samples = captureSamples(captureDevice, frequency, keywordLength);
Alc.CaptureStop(captureDevice);
int fileIndex = 0;
while (File.Exists($"{keywordName}.{fileIndex}.wav"))
{
fileIndex += 1;
}
// write sound file
{
string filename = $"{keywordName}.{fileIndex}.wav";
Debug.Assert(samples.Length >= keywordLength);
var wavFile = new WavFile(filename)
{
SamplesPerSecond = frequency, SamplesTotalCount = keywordLength /* trim samples */
};
wavFile.WriteMono16bit(samples);
Console.WriteLine($"wav file was saved.");
}
// create spectrogram and save as image
{
int width = (int)Math.Sqrt(samples.Length * 2); // TODO: make better formula for square images
var bins = samples.Partition(size: width);
var spectrogram = new List <double[]>();
foreach (var bin in bins)
{
double[] histogram = calculateFFT(bin.ToArray());
spectrogram.Add(histogram);
}
using (Bitmap bitmap = new Bitmap(spectrogram.Count, spectrogram[0].Length))
{
for (int i = 0; i < spectrogram.Count; i++)
{
for (int j = 0; j < spectrogram[i].Length; j++)
{
double value = spectrogram[i][j];
double pixelValue = Math.Max(0, Math.Min(255, value * 10)); // TODO: do not trim values, make better multiplying factor
byte color = (byte)(pixelValue);
bitmap.SetPixel(i, j, Color.FromArgb(color, color, color));
}
}
string filename = $"{keywordName}.{fileIndex}.png";
bitmap.Save(filename, ImageFormat.Png);
Console.WriteLine($"png file was saved.");
}
}
}
}
else
{
Alc.CaptureStart(captureDevice);
Console.WriteLine("listening for keyword..."); // need new line for intensity visualization
var reporter = new ClapDetector.Client.Reporter();
while (true)
{
short[] samples = captureSamples(captureDevice, frequency, keywordLength);
// TODO: generate spectrogram image and compare to existing models
Console.WriteLine("samples taken");
string replyMessage = await reporter.ReportClapAsync();
System.Console.WriteLine($"[{DateTime.UtcNow:HH:mm:ss.fff}]: {replyMessage}");
}
Alc.CaptureStop(captureDevice);
}
// clean up
Alc.CaptureCloseDevice(captureDevice);
Alc.MakeContextCurrent(IntPtr.Zero);
//Alc.DestroyContext(context);
//Alc.CloseDevice(audioDevice);
}