apps/CtsVerifier/src/com/android/cts/verifier/audio/WavAnalyzer.java - platform/cts - Git at Google

 package com.android.cts.verifier.audio;

 import org.apache.commons.math.complex.Complex;

 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;

 /**
  * Class contains the analysis to calculate frequency response.
  */
 public class WavAnalyzer {
   private final Listener listener;
   private final int sampleRate;  // Recording sampling rate.
   private double[] data;  // Whole recording data.
   private double[] dB;  // Average response
   private double[][] power;  // power of each trial
   private double[] noiseDB;  // background noise
   private double[][] noisePower;
   private double threshold;  // threshold of passing, drop off compared to 2000 kHz
   private boolean result = false;  // result of the test

   /**
    * Constructor of WavAnalyzer.
    */
   public WavAnalyzer(byte[] byteData, int sampleRate, Listener listener) {
     this.listener = listener;
     this.sampleRate = sampleRate;

     short[] shortData = new short[byteData.length >> 1];
     ByteBuffer.wrap(byteData).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shortData);
     this.data = Util.toDouble(shortData);
     for (int i = 0; i < data.length; i++) {
       data[i] = data[i] / Short.MAX_VALUE;
     }
   }

   /**
    * Do the analysis. Returns true if passing, false if failing.
    */
   public boolean doWork() {
     if (isClipped()) {
       return false;
     }
     // Calculating the pip strength.
     listener.sendMessage("Calculating... Please wait...\n");
     try {
       dB = measurePipStrength();
     } catch (IndexOutOfBoundsException e) {
       listener.sendMessage("WARNING: May have missed the prefix."
           + " Turn up the volume of the playback device or move to a quieter location.\n");
       return false;
     }
     if (!isConsistent()) {
       return false;
     }
     result = responsePassesHifiTest(dB);
     return result;
   }

   /**
    * Check if the recording is clipped.
    */
   boolean isClipped() {
     for (int i = 1; i < data.length; i++) {
       if ((Math.abs(data[i]) >= Short.MAX_VALUE) && (Math.abs(data[i - 1]) >= Short.MAX_VALUE)) {
         listener.sendMessage("WARNING: Data is clipped."
             + " Turn down the volume of the playback device and redo the procedure.\n");
         return true;
       }
     }
     return false;
   }

   /**
    * Check if the result is consistant across trials.
    */
   boolean isConsistent() {
     double[] coeffOfVar = new double[Common.PIP_NUM];
     for (int i = 0; i < Common.PIP_NUM; i++) {
       double[] powerAtFreq = new double[Common.REPETITIONS];
       for (int j = 0; j < Common.REPETITIONS; j++) {
         powerAtFreq[j] = power[i][j];
       }
       coeffOfVar[i] = Util.std(powerAtFreq) / Util.mean(powerAtFreq);
     }
     if (Util.mean(coeffOfVar) > 1.0) {
       listener.sendMessage("WARNING: Inconsistent result across trials."
           + " Turn up the volume of the playback device or move to a quieter location.\n");
       return false;
     }
     return true;
   }

   /**
    * Determine test pass/fail using the frequency response. Package visible for unit testing.
    */
   boolean responsePassesHifiTest(double[] dB) {
     for (int i = 0; i < dB.length; i++) {
       // Precautionary; NaN should not happen.
       if (Double.isNaN(dB[i])) {
         listener.sendMessage(
             "WARNING: Unexpected NaN in result. Redo the test.\n");
         return false;
       }
     }

     if (Util.mean(dB) - Util.mean(noiseDB) < Common.SIGNAL_MIN_STRENGTH_DB_ABOVE_NOISE) {
       listener.sendMessage("WARNING: Signal is too weak or background noise is too strong."
           + " Turn up the volume of the playback device or move to a quieter location.\n");
       return false;
     }

     int indexOf2000Hz = Util.findClosest(Common.FREQUENCIES_ORIGINAL, 2000.0);
     threshold = dB[indexOf2000Hz] + Common.PASSING_THRESHOLD_DB;
     int indexOf18500Hz = Util.findClosest(Common.FREQUENCIES_ORIGINAL, 18500.0);
     int indexOf20000Hz = Util.findClosest(Common.FREQUENCIES_ORIGINAL, 20000.0);
     double[] responseInRange = new double[indexOf20000Hz - indexOf18500Hz];
     System.arraycopy(dB, indexOf18500Hz, responseInRange, 0, responseInRange.length);
     if (Util.mean(responseInRange) < threshold) {
       listener.sendMessage(
           "WARNING: Failed. Retry with different orientations or report failed.\n");
       return false;
     }
     return true;
   }

   /**
    * Calculate the Fourier Coefficient at the pip frequency to calculate the frequency response.
    * Package visible for unit testing.
    */
   double[] measurePipStrength() {
     listener.sendMessage("Aligning data... Please wait...\n");
     final int dataStartI = alignData();
     final int prefixTotalLength = dataStartI
         + Util.toLength(Common.PREFIX_LENGTH_S + Common.PAUSE_AFTER_PREFIX_DURATION_S, sampleRate);
     listener.sendMessage("Done.\n");
     listener.sendMessage("Prefix starts at " + (double) dataStartI / sampleRate + " s \n");
     if (dataStartI > Math.round(sampleRate * (Common.PREFIX_LENGTH_S
             + Common.PAUSE_BEFORE_PREFIX_DURATION_S + Common.PAUSE_AFTER_PREFIX_DURATION_S))) {
       listener.sendMessage("WARNING: Unexpected prefix start time. May have missed the prefix.\n"
           + "PLAY button should be pressed on the playback device within one second"
           + " after RECORD is pressed on the recording device.\n"
           + "If this happens repeatedly,"
           + " turn up the volume of the playback device or move to a quieter location.\n");
     }

     listener.sendMessage("Analyzing noise strength... Please wait...\n");
     noisePower = new double[Common.PIP_NUM][Common.NOISE_SAMPLES];
     noiseDB = new double[Common.PIP_NUM];
     for (int s = 0; s < Common.NOISE_SAMPLES; s++) {
       double[] noisePoints = new double[Common.WINDOW_FOR_RECORDER.length];
       System.arraycopy(data, dataStartI - (s + 1) * noisePoints.length - 1,
           noisePoints, 0, noisePoints.length);
       for (int j = 0; j < noisePoints.length; j++) {
         noisePoints[j] = noisePoints[j] * Common.WINDOW_FOR_RECORDER[j];
       }
       for (int i = 0; i < Common.PIP_NUM; i++) {
         double freq = Common.FREQUENCIES_ORIGINAL[i];
         Complex fourierCoeff = new Complex(0, 0);
         final Complex rotator = new Complex(0,
             -2.0 * Math.PI * freq / sampleRate).exp();
         Complex phasor = new Complex(1, 0);
         for (int j = 0; j < noisePoints.length; j++) {
           fourierCoeff = fourierCoeff.add(phasor.multiply(noisePoints[j]));
           phasor = phasor.multiply(rotator);
         }
         fourierCoeff = fourierCoeff.multiply(1.0 / noisePoints.length);
         noisePower[i][s] = fourierCoeff.multiply(fourierCoeff.conjugate()).abs();
       }
     }
     for (int i = 0; i < Common.PIP_NUM; i++) {
       double meanNoisePower = 0;
       for (int j = 0; j < Common.NOISE_SAMPLES; j++) {
         meanNoisePower += noisePower[i][j];
       }
       meanNoisePower /= Common.NOISE_SAMPLES;
       noiseDB[i] = 10 * Math.log10(meanNoisePower);
     }

     listener.sendMessage("Analyzing pips... Please wait...\n");
     power = new double[Common.PIP_NUM][Common.REPETITIONS];
     for (int i = 0; i < Common.PIP_NUM * Common.REPETITIONS; i++) {
       if (i % Common.PIP_NUM == 0) {
         listener.sendMessage("#" + (i / Common.PIP_NUM + 1) + "\n");
       }

       int pipExpectedStartI;
       pipExpectedStartI = prefixTotalLength
           + Util.toLength(i * (Common.PIP_DURATION_S + Common.PAUSE_DURATION_S), sampleRate);
       // Cut out the data points for the current pip.
       double[] pipPoints = new double[Common.WINDOW_FOR_RECORDER.length];
       System.arraycopy(data, pipExpectedStartI, pipPoints, 0, pipPoints.length);
       for (int j = 0; j < Common.WINDOW_FOR_RECORDER.length; j++) {
         pipPoints[j] = pipPoints[j] * Common.WINDOW_FOR_RECORDER[j];
       }
       Complex fourierCoeff = new Complex(0, 0);
       final Complex rotator = new Complex(0,
           -2.0 * Math.PI * Common.FREQUENCIES[i] / sampleRate).exp();
       Complex phasor = new Complex(1, 0);
       for (int j = 0; j < pipPoints.length; j++) {
         fourierCoeff = fourierCoeff.add(phasor.multiply(pipPoints[j]));
         phasor = phasor.multiply(rotator);
       }
       fourierCoeff = fourierCoeff.multiply(1.0 / pipPoints.length);
       int j = Common.ORDER[i];
       power[j % Common.PIP_NUM][j / Common.PIP_NUM] =
           fourierCoeff.multiply(fourierCoeff.conjugate()).abs();
     }

     // Calculate median of trials.
     double[] dB = new double[Common.PIP_NUM];
     for (int i = 0; i < Common.PIP_NUM; i++) {
       dB[i] = 10 * Math.log10(Util.median(power[i]));
     }
     return dB;
   }

   /**
    * Align data using prefix. Package visible for unit testing.
    */
   int alignData() {
     // Zeropadding samples to add in the correlation to avoid FFT wraparound.
     final int zeroPad = Util.toLength(Common.PREFIX_LENGTH_S, Common.RECORDING_SAMPLE_RATE_HZ) - 1;
     int fftSize = Util.nextPowerOfTwo((int) Math.round(sampleRate * (Common.PREFIX_LENGTH_S
             + Common.PAUSE_BEFORE_PREFIX_DURATION_S + Common.PAUSE_AFTER_PREFIX_DURATION_S + 0.5))
         + zeroPad);

     double[] dataCut = new double[fftSize - zeroPad];
     System.arraycopy(data, 0, dataCut, 0, fftSize - zeroPad);
     double[] xCorrDataPrefix = Util.computeCrossCorrelation(
         Util.padZeros(Util.toComplex(dataCut), fftSize),
         Util.padZeros(Util.toComplex(Common.PREFIX_FOR_RECORDER), fftSize));
     return Util.findMaxIndex(xCorrDataPrefix);
   }

   double[] getDB() {
     return dB;
   }

   double[][] getPower() {
     return power;
   }

   double[] getNoiseDB() {
     return noiseDB;
   }

   double getThreshold() {
     return threshold;
   }

   boolean getResult() {
     return result;
   }

   /**
    * An interface for listening a message publishing the progress of the analyzer.
    */
   public interface Listener {

     void sendMessage(String message);
   }
 }
	package com.android.cts.verifier.audio;

	import org.apache.commons.math.complex.Complex;

	import java.nio.ByteBuffer;
	import java.nio.ByteOrder;

	/**
	* Class contains the analysis to calculate frequency response.
	*/
	public class WavAnalyzer {
	private final Listener listener;
	private final int sampleRate; // Recording sampling rate.
	private double[] data; // Whole recording data.
	private double[] dB; // Average response
	private double[][] power; // power of each trial
	private double[] noiseDB; // background noise
	private double[][] noisePower;
	private double threshold; // threshold of passing, drop off compared to 2000 kHz
	private boolean result = false; // result of the test

	/**
	* Constructor of WavAnalyzer.
	*/
	public WavAnalyzer(byte[] byteData, int sampleRate, Listener listener) {
	this.listener = listener;
	this.sampleRate = sampleRate;

	short[] shortData = new short[byteData.length >> 1];
	ByteBuffer.wrap(byteData).order(ByteOrder.LITTLE_ENDIAN).asShortBuffer().get(shortData);
	this.data = Util.toDouble(shortData);
	for (int i = 0; i < data.length; i++) {
	data[i] = data[i] / Short.MAX_VALUE;
	}
	}

	/**
	* Do the analysis. Returns true if passing, false if failing.
	*/
	public boolean doWork() {
	if (isClipped()) {
	return false;
	}
	// Calculating the pip strength.
	listener.sendMessage("Calculating... Please wait...\n");
	try {
	dB = measurePipStrength();
	} catch (IndexOutOfBoundsException e) {
	listener.sendMessage("WARNING: May have missed the prefix."
	+ " Turn up the volume of the playback device or move to a quieter location.\n");
	return false;
	}
	if (!isConsistent()) {
	return false;
	}
	result = responsePassesHifiTest(dB);
	return result;
	}

	/**
	* Check if the recording is clipped.
	*/
	boolean isClipped() {
	for (int i = 1; i < data.length; i++) {
	if ((Math.abs(data[i]) >= Short.MAX_VALUE) && (Math.abs(data[i - 1]) >= Short.MAX_VALUE)) {
	listener.sendMessage("WARNING: Data is clipped."
	+ " Turn down the volume of the playback device and redo the procedure.\n");
	return true;
	}
	}
	return false;
	}

	/**
	* Check if the result is consistant across trials.
	*/
	boolean isConsistent() {
	double[] coeffOfVar = new double[Common.PIP_NUM];
	for (int i = 0; i < Common.PIP_NUM; i++) {
	double[] powerAtFreq = new double[Common.REPETITIONS];
	for (int j = 0; j < Common.REPETITIONS; j++) {
	powerAtFreq[j] = power[i][j];
	}
	coeffOfVar[i] = Util.std(powerAtFreq) / Util.mean(powerAtFreq);
	}
	if (Util.mean(coeffOfVar) > 1.0) {
	listener.sendMessage("WARNING: Inconsistent result across trials."
	+ " Turn up the volume of the playback device or move to a quieter location.\n");
	return false;
	}
	return true;
	}

	/**
	* Determine test pass/fail using the frequency response. Package visible for unit testing.
	*/
	boolean responsePassesHifiTest(double[] dB) {
	for (int i = 0; i < dB.length; i++) {
	// Precautionary; NaN should not happen.
	if (Double.isNaN(dB[i])) {
	listener.sendMessage(
	"WARNING: Unexpected NaN in result. Redo the test.\n");
	return false;
	}
	}

	if (Util.mean(dB) - Util.mean(noiseDB) < Common.SIGNAL_MIN_STRENGTH_DB_ABOVE_NOISE) {
	listener.sendMessage("WARNING: Signal is too weak or background noise is too strong."
	+ " Turn up the volume of the playback device or move to a quieter location.\n");
	return false;
	}

	int indexOf2000Hz = Util.findClosest(Common.FREQUENCIES_ORIGINAL, 2000.0);
	threshold = dB[indexOf2000Hz] + Common.PASSING_THRESHOLD_DB;
	int indexOf18500Hz = Util.findClosest(Common.FREQUENCIES_ORIGINAL, 18500.0);
	int indexOf20000Hz = Util.findClosest(Common.FREQUENCIES_ORIGINAL, 20000.0);
	double[] responseInRange = new double[indexOf20000Hz - indexOf18500Hz];
	System.arraycopy(dB, indexOf18500Hz, responseInRange, 0, responseInRange.length);
	if (Util.mean(responseInRange) < threshold) {
	listener.sendMessage(
	"WARNING: Failed. Retry with different orientations or report failed.\n");
	return false;
	}
	return true;
	}

	/**
	* Calculate the Fourier Coefficient at the pip frequency to calculate the frequency response.
	* Package visible for unit testing.
	*/
	double[] measurePipStrength() {
	listener.sendMessage("Aligning data... Please wait...\n");
	final int dataStartI = alignData();
	final int prefixTotalLength = dataStartI
	+ Util.toLength(Common.PREFIX_LENGTH_S + Common.PAUSE_AFTER_PREFIX_DURATION_S, sampleRate);
	listener.sendMessage("Done.\n");
	listener.sendMessage("Prefix starts at " + (double) dataStartI / sampleRate + " s \n");
	if (dataStartI > Math.round(sampleRate * (Common.PREFIX_LENGTH_S
	+ Common.PAUSE_BEFORE_PREFIX_DURATION_S + Common.PAUSE_AFTER_PREFIX_DURATION_S))) {
	listener.sendMessage("WARNING: Unexpected prefix start time. May have missed the prefix.\n"
	+ "PLAY button should be pressed on the playback device within one second"
	+ " after RECORD is pressed on the recording device.\n"
	+ "If this happens repeatedly,"
	+ " turn up the volume of the playback device or move to a quieter location.\n");
	}

	listener.sendMessage("Analyzing noise strength... Please wait...\n");
	noisePower = new double[Common.PIP_NUM][Common.NOISE_SAMPLES];
	noiseDB = new double[Common.PIP_NUM];
	for (int s = 0; s < Common.NOISE_SAMPLES; s++) {
	double[] noisePoints = new double[Common.WINDOW_FOR_RECORDER.length];
	System.arraycopy(data, dataStartI - (s + 1) * noisePoints.length - 1,
	noisePoints, 0, noisePoints.length);
	for (int j = 0; j < noisePoints.length; j++) {
	noisePoints[j] = noisePoints[j] * Common.WINDOW_FOR_RECORDER[j];
	}
	for (int i = 0; i < Common.PIP_NUM; i++) {
	double freq = Common.FREQUENCIES_ORIGINAL[i];
	Complex fourierCoeff = new Complex(0, 0);
	final Complex rotator = new Complex(0,
	-2.0 * Math.PI * freq / sampleRate).exp();
	Complex phasor = new Complex(1, 0);
	for (int j = 0; j < noisePoints.length; j++) {
	fourierCoeff = fourierCoeff.add(phasor.multiply(noisePoints[j]));
	phasor = phasor.multiply(rotator);
	}
	fourierCoeff = fourierCoeff.multiply(1.0 / noisePoints.length);
	noisePower[i][s] = fourierCoeff.multiply(fourierCoeff.conjugate()).abs();
	}
	}
	for (int i = 0; i < Common.PIP_NUM; i++) {
	double meanNoisePower = 0;
	for (int j = 0; j < Common.NOISE_SAMPLES; j++) {
	meanNoisePower += noisePower[i][j];
	}
	meanNoisePower /= Common.NOISE_SAMPLES;
	noiseDB[i] = 10 * Math.log10(meanNoisePower);
	}

	listener.sendMessage("Analyzing pips... Please wait...\n");
	power = new double[Common.PIP_NUM][Common.REPETITIONS];
	for (int i = 0; i < Common.PIP_NUM * Common.REPETITIONS; i++) {
	if (i % Common.PIP_NUM == 0) {
	listener.sendMessage("#" + (i / Common.PIP_NUM + 1) + "\n");
	}

	int pipExpectedStartI;
	pipExpectedStartI = prefixTotalLength
	+ Util.toLength(i * (Common.PIP_DURATION_S + Common.PAUSE_DURATION_S), sampleRate);
	// Cut out the data points for the current pip.
	double[] pipPoints = new double[Common.WINDOW_FOR_RECORDER.length];
	System.arraycopy(data, pipExpectedStartI, pipPoints, 0, pipPoints.length);
	for (int j = 0; j < Common.WINDOW_FOR_RECORDER.length; j++) {
	pipPoints[j] = pipPoints[j] * Common.WINDOW_FOR_RECORDER[j];
	}
	Complex fourierCoeff = new Complex(0, 0);
	final Complex rotator = new Complex(0,
	-2.0 * Math.PI * Common.FREQUENCIES[i] / sampleRate).exp();
	Complex phasor = new Complex(1, 0);
	for (int j = 0; j < pipPoints.length; j++) {
	fourierCoeff = fourierCoeff.add(phasor.multiply(pipPoints[j]));
	phasor = phasor.multiply(rotator);
	}
	fourierCoeff = fourierCoeff.multiply(1.0 / pipPoints.length);
	int j = Common.ORDER[i];
	power[j % Common.PIP_NUM][j / Common.PIP_NUM] =
	fourierCoeff.multiply(fourierCoeff.conjugate()).abs();
	}

	// Calculate median of trials.
	double[] dB = new double[Common.PIP_NUM];
	for (int i = 0; i < Common.PIP_NUM; i++) {
	dB[i] = 10 * Math.log10(Util.median(power[i]));
	}
	return dB;
	}

	/**
	* Align data using prefix. Package visible for unit testing.
	*/
	int alignData() {
	// Zeropadding samples to add in the correlation to avoid FFT wraparound.
	final int zeroPad = Util.toLength(Common.PREFIX_LENGTH_S, Common.RECORDING_SAMPLE_RATE_HZ) - 1;
	int fftSize = Util.nextPowerOfTwo((int) Math.round(sampleRate * (Common.PREFIX_LENGTH_S
	+ Common.PAUSE_BEFORE_PREFIX_DURATION_S + Common.PAUSE_AFTER_PREFIX_DURATION_S + 0.5))
	+ zeroPad);

	double[] dataCut = new double[fftSize - zeroPad];
	System.arraycopy(data, 0, dataCut, 0, fftSize - zeroPad);
	double[] xCorrDataPrefix = Util.computeCrossCorrelation(
	Util.padZeros(Util.toComplex(dataCut), fftSize),
	Util.padZeros(Util.toComplex(Common.PREFIX_FOR_RECORDER), fftSize));
	return Util.findMaxIndex(xCorrDataPrefix);
	}

	double[] getDB() {
	return dB;
	}

	double[][] getPower() {
	return power;
	}

	double[] getNoiseDB() {
	return noiseDB;
	}

	double getThreshold() {
	return threshold;
	}

	boolean getResult() {
	return result;
	}

	/**
	* An interface for listening a message publishing the progress of the analyzer.
	*/
	public interface Listener {

	void sendMessage(String message);
	}
	}