private unsafe static short[] captureSamples(IntPtr captureDevice, int frequency, int sampleCount)
{
short[] samples = new short[sampleCount];
int samplesTaken = 0;
bool isRecording = false;
double?previousRMS = null;
short[] buffer = new short[frequency];
fixed(int *samplesAvailable = new int[1])
fixed(short *bufferPointer = buffer)
{
while (samplesTaken < sampleCount)
{
IntPtr samplesAvailablePointer = new IntPtr((void *)samplesAvailable);
Alc.GetIntegerv(captureDevice, Alc.EnumCaptureSamples, 1, samplesAvailablePointer);
int samplesAvailableCount = samplesAvailable[0];
const int captureCount = 2048;
if (samplesAvailableCount > captureCount)
{
Alc.CaptureSamples(captureDevice, (void *)bufferPointer, samplesAvailableCount);
// TODO: ... do something with the buffer
double rms = calculateRMS(buffer, samplesAvailableCount);
double maxAmplitude = short.MaxValue;
double intensity = rms / maxAmplitude;
printIntensity(intensity);
// compare current rms with previous values to find beginning of a keyword
const double factor = 10;
if (rms > previousRMS * factor) // beginning of window
{
isRecording = true;
//Console.Beep(10000, 10);
}
if (isRecording)
{
for (int i = 0; i < samplesAvailableCount; i++)
{
samples[samplesTaken++] = buffer[i];
if (samplesTaken == sampleCount)
{
goto done;
}
}
}
previousRMS = rms;
}
}
}
done:
resetConsoleSettings();
return(samples.ToArray());
}