core.be.tarsos.dsp.SilenceDetector Maven / Gradle / Ivy
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/*
* _______ _____ _____ _____
* |__ __| | __ \ / ____| __ \
* | | __ _ _ __ ___ ___ ___| | | | (___ | |__) |
* | |/ _` | '__/ __|/ _ \/ __| | | |\___ \| ___/
* | | (_| | | \__ \ (_) \__ \ |__| |____) | |
* |_|\__,_|_| |___/\___/|___/_____/|_____/|_|
*
* -------------------------------------------------------------
*
* TarsosDSP is developed by Joren Six at IPEM, University Ghent
*
* -------------------------------------------------------------
*
* Info: http://0110.be/tag/TarsosDSP
* Github: https://github.com/JorenSix/TarsosDSP
* Releases: http://0110.be/releases/TarsosDSP/
*
* TarsosDSP includes modified source code by various authors,
* for credits and info, see README.
*
*/
package be.tarsos.dsp;
/**
* The continuing silence detector does not break the audio processing pipeline when silence is detected.
*/
public class SilenceDetector implements AudioProcessor {
public static final double DEFAULT_SILENCE_THRESHOLD = -70.0;//db
private final double threshold;//db
private final boolean breakProcessingQueueOnSilence;
/**
* Create a new silence detector with a default threshold.
*/
public SilenceDetector(){
this(DEFAULT_SILENCE_THRESHOLD,false);
}
/**
* Create a new silence detector with a defined threshold.
*
* @param silenceThreshold
* The threshold which defines when a buffer is silent (in dB).
* Normal values are [-70.0,-30.0] dB SPL.
* @param breakProcessingQueueOnSilence
*/
public SilenceDetector(final double silenceThreshold,boolean breakProcessingQueueOnSilence){
this.threshold = silenceThreshold;
this.breakProcessingQueueOnSilence = breakProcessingQueueOnSilence;
}
/**
* Calculates the local (linear) energy of an audio buffer.
*
* @param buffer
* The audio buffer.
* @return The local (linear) energy of an audio buffer.
*/
private double localEnergy(final float[] buffer) {
double power = 0.0D;
for (float element : buffer) {
power += element * element;
}
return power;
}
/**
* Returns the dBSPL for a buffer.
*
* @param buffer
* The buffer with audio information.
* @return The dBSPL level for the buffer.
*/
private double soundPressureLevel(final float[] buffer) {
double value = Math.pow(localEnergy(buffer), 0.5);
value = value / buffer.length;
return linearToDecibel(value);
}
/**
* Converts a linear to a dB value.
*
* @param value
* The value to convert.
* @return The converted value.
*/
private double linearToDecibel(final double value) {
return 20.0 * Math.log10(value);
}
double currentSPL = 0;
public double currentSPL(){
return currentSPL;
}
/**
* Checks if the dBSPL level in the buffer falls below a certain threshold.
*
* @param buffer
* The buffer with audio information.
* @param silenceThreshold
* The threshold in dBSPL
* @return True if the audio information in buffer corresponds with silence,
* false otherwise.
*/
public boolean isSilence(final float[] buffer, final double silenceThreshold) {
currentSPL = soundPressureLevel(buffer);
return currentSPL < silenceThreshold;
}
public boolean isSilence(final float[] buffer) {
return isSilence(buffer, threshold);
}
@Override
public boolean process(AudioEvent audioEvent) {
boolean isSilence = isSilence(audioEvent.getFloatBuffer());
//break processing chain on silence?
if(breakProcessingQueueOnSilence){
//break if silent
return !isSilence;
}else{
//never break the chain
return true;
}
}
@Override
public void processingFinished() {
}
}