/**
* E than the specified threshold
*
* @param buf buffer to save the signal frame
* @return true on success, false if the audio stream terminated before a window with sufficient
* energy could be found
*/
public static double calcThresholdFromSilence(FrameSource source) throws IOException {
double[] buf = new double[source.getFrameSize()];
double sum = 0.0;
int n = 0;
while (source.read(buf)) {
double energy = 0.0;
for (int i = 0; i < source.getFrameSize(); i++) {
energy += buf[i] * buf[i];
}
energy /= source.getFrameSize();
System.out.println(energy);
sum += energy;
n++;
}
sum /= n;
return sum;
}
/**
* Read from the given source as long as a window is found, that is higher than the specified
* threshold
*
* @param buf buffer to save the signal frame
* @return true on success, false if the audio stream terminated before a window with sufficient
* energy could be found
*/
public boolean read(double[] buf) throws IOException {
while (source.read(buf)) {
/* calculate energy for the entire window */
double energy = 0.0;
for (int i = 0; i < fs; i++) {
energy += buf[i] * buf[i];
}
energy /= fs;
if (energy > threshold) {
return true;
}
}
return false;
}
/** Return the outgoing frame size */
public int getFrameSize() {
return source.getFrameSize();
}
/**
* Initializes the EnergyDector
*
* @param source FrameSource to read from
* @param threshold threshold for voice activity decision
*/
public EnergyDetector(FrameSource source, double threshold) {
this.source = source;
fs = source.getFrameSize();
this.threshold = threshold;
}