public void setWindowType(WindowType windowType) {
mWindowType = windowType;
if (mSampleType == SampleType.COMPLEX) {
mWindow = Window.getWindow(mWindowType, mDFTSize.getSize() * 2);
} else {
mWindow = Window.getWindow(mWindowType, mDFTSize.getSize());
}
}
private void calculateConsumptionRate() {
mNewFloatResidual = 0.0f;
mNewFloatsPerFrame =
((float) mSampleRate / (float) mFrameRate)
* (mSampleType == SampleType.COMPLEX ? 2.0f : 1.0f);
mFFTFloatsPerFrame =
(mSampleType == SampleType.COMPLEX ? mDFTSize.getSize() * 2 : mDFTSize.getSize());
}
/**
* Checks for a queued FFT width change request and applies it. This method will only be accessed
* by the scheduled executor that gains access to run a calculate method, thus providing thread
* safety.
*/
private void checkFFTSize() {
if (mNewDFTSize.getSize() != mDFTSize.getSize()) {
mDFTSize = mNewDFTSize;
calculateConsumptionRate();
setWindowType(mWindowType);
if (mSampleType == SampleType.COMPLEX) {
mPreviousFrame = new float[mDFTSize.getSize() * 2];
} else {
mPreviousFrame = new float[mDFTSize.getSize()];
}
mFFT = new FloatFFT_1D(mDFTSize.getSize());
}
}
/**
* Processes both complex samples or float samples and dispatches a float array of DFT results,
* using configurable fft size and output dispatch timelines.
*/
public class DFTProcessor
implements Listener<ComplexBuffer>, FrequencyChangeListener, IDFTWidthChangeProcessor {
private static final Logger mLog = LoggerFactory.getLogger(DFTProcessor.class);
private CopyOnWriteArrayList<DFTResultsConverter> mListeners =
new CopyOnWriteArrayList<DFTResultsConverter>();
private ArrayBlockingQueue<ComplexBuffer> mQueue = new ArrayBlockingQueue<ComplexBuffer>(200);
private ScheduledExecutorService mScheduler =
Executors.newScheduledThreadPool(1, new NamingThreadFactory("spectrum dft"));
public static final String FRAME_RATE_PROPERTY = "spectral.display.frame.rate";
private DFTSize mDFTSize = DFTSize.FFT04096;
private DFTSize mNewDFTSize = DFTSize.FFT04096;
private double[] mWindow;
/* The Cosine and Hanning windows seem to offer the best spectral display
* with minimal bin leakage/smearing */
private WindowType mWindowType = Window.WindowType.HANNING;
private FloatFFT_1D mFFT = new FloatFFT_1D(mDFTSize.getSize());
private int mFrameRate;
private int mSampleRate;
private int mFFTFloatsPerFrame;
private float mNewFloatsPerFrame;
private float mNewFloatResidual;
private float[] mPreviousFrame = new float[8192];
private float[] mCurrentBuffer;
private int mCurrentBufferPointer = 0;
private SampleType mSampleType;
private AtomicBoolean mRunning = new AtomicBoolean();
public DFTProcessor(SampleType sampleType) {
setSampleType(sampleType);
loadSettings();
}
private void loadSettings() {
int frameRate = SystemProperties.getInstance().get(DFTProcessor.FRAME_RATE_PROPERTY, 20);
setFrameRate(frameRate);
}
public void dispose() {
stop();
mListeners.clear();
mQueue.clear();
mWindow = null;
mCurrentBuffer = null;
}
public WindowType getWindowType() {
return mWindowType;
}
public void setWindowType(WindowType windowType) {
mWindowType = windowType;
if (mSampleType == SampleType.COMPLEX) {
mWindow = Window.getWindow(mWindowType, mDFTSize.getSize() * 2);
} else {
mWindow = Window.getWindow(mWindowType, mDFTSize.getSize());
}
}
/**
* Sets the processor mode to Float or Complex, depending on the sample types that will be
* delivered for processing
*/
public void setSampleType(SampleType type) {
mSampleType = type;
setWindowType(mWindowType);
}
public SampleType getSampleType() {
return mSampleType;
}
/**
* Queues an FFT size change request. The scheduled executor will apply the change when it runs.
*/
public void setDFTSize(DFTSize size) {
mNewDFTSize = size;
}
public DFTSize getDFTSize() {
return mDFTSize;
}
public int getFrameRate() {
return mFrameRate;
}
public void setFrameRate(int framesPerSecond) {
// TODO: make sure frame rate & sample rate sample requirement doesn't
// expect overlap greater than the previous frame length
if (framesPerSecond < 1 || framesPerSecond > 1000) {
throw new IllegalArgumentException(
"DFTProcessor cannot run "
+ "more than 1000 times per second -- requested setting:"
+ framesPerSecond);
}
mFrameRate = framesPerSecond;
SystemProperties properties = SystemProperties.getInstance();
properties.set(FRAME_RATE_PROPERTY, String.valueOf(mFrameRate));
properties.save();
calculateConsumptionRate();
restart();
}
public void start() {
/** Reset the scheduler */
mScheduler = Executors.newScheduledThreadPool(1, new NamingThreadFactory("spectrum dft"));
/** Schedule the DFT to run calculations at a fixed rate */
int initialDelay = 0;
int period = (int) (1000 / mFrameRate);
TimeUnit unit = TimeUnit.MILLISECONDS;
mScheduler.scheduleAtFixedRate(new DFTCalculationTask(), initialDelay, period, unit);
}
public void stop() {
/** Shutdown the scheduler and clear out any remaining tasks */
try {
mScheduler.shutdown();
mScheduler.awaitTermination(100, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
/* Do nothing ... we're shutting down */
// mLog.error( "DFTProcessor - exception while awaiting shutdown of "
// + "calculation scheduler for reset", e );
}
}
public void restart() {
stop();
start();
}
public int getCalculationsPerSecond() {
return mFrameRate;
}
/** Places the sample into a transfer queue for future processing. */
@Override
public void receive(ComplexBuffer sampleBuffer) {
if (!mQueue.offer(sampleBuffer)) {
mLog.error(
"DFTProcessor - ["
+ mSampleType.toString()
+ "] queue is full, purging queue, "
+ "samples["
+ sampleBuffer
+ "]");
mQueue.clear();
mQueue.offer(sampleBuffer);
}
}
private void getNextBuffer() {
mCurrentBuffer = null;
try {
Buffer buffer = mQueue.take();
mCurrentBuffer = buffer.getSamples();
} catch (InterruptedException e) {
mCurrentBuffer = null;
}
mCurrentBufferPointer = 0;
}
private float[] getSamples() {
int remaining = (int) mFFTFloatsPerFrame;
float[] currentFrame = new float[remaining];
int currentFramePointer = 0;
float integralFloatsToConsume = mNewFloatsPerFrame + mNewFloatResidual;
int newFloatsToConsumeThisFrame = (int) integralFloatsToConsume;
mNewFloatResidual = integralFloatsToConsume - newFloatsToConsumeThisFrame;
/* If the number of required floats for the fft is greater than the
* consumption rate per frame, we have to reach into the previous
* frame to makeup the difference. */
if (newFloatsToConsumeThisFrame < remaining) {
int previousFloatsRequired = remaining - newFloatsToConsumeThisFrame;
System.arraycopy(
mPreviousFrame,
mPreviousFrame.length - previousFloatsRequired,
currentFrame,
currentFramePointer,
previousFloatsRequired);
remaining -= previousFloatsRequired;
currentFramePointer += previousFloatsRequired;
}
/* Fill the rest of the buffer with new samples */
while (mRunning.get() && remaining > 0) {
if (mCurrentBuffer == null || mCurrentBufferPointer >= mCurrentBuffer.length) {
getNextBuffer();
}
/* If we don't have new samples to use, send the current frame with
* the remaining values as zero */
if (mCurrentBuffer == null) {
remaining = 0;
} else {
int samplesAvailable = mCurrentBuffer.length - mCurrentBufferPointer;
while (remaining > 0 && samplesAvailable > 0) {
currentFrame[currentFramePointer++] = (float) mCurrentBuffer[mCurrentBufferPointer++];
samplesAvailable--;
remaining--;
newFloatsToConsumeThisFrame--;
}
}
}
/* If the incoming float rate is greater than the fft consumption rate,
* then we have to purge some floats, otherwise, store the previous
* frame, because we have overlapping frames */
if (newFloatsToConsumeThisFrame > 0) {
purge(newFloatsToConsumeThisFrame);
} else {
mPreviousFrame = Arrays.copyOf(currentFrame, currentFrame.length);
}
return currentFrame;
}
private void calculate() {
float[] samples = getSamples();
Window.apply(mWindow, samples);
if (mSampleType == SampleType.REAL) {
mFFT.realForward(samples);
} else {
mFFT.complexForward(samples);
}
dispatch(samples);
}
private void purge(int samplesToPurge) {
if (samplesToPurge <= 0) {
throw new IllegalArgumentException("DFTProcessor - cannot purge " + "negative sample amount");
}
while (mRunning.get() && samplesToPurge > 0) {
if (mCurrentBuffer == null || mCurrentBufferPointer >= mCurrentBuffer.length) {
getNextBuffer();
}
if (mCurrentBuffer != null) {
int samplesAvailable = mCurrentBuffer.length - mCurrentBufferPointer;
if (samplesAvailable >= samplesToPurge) {
mCurrentBufferPointer += samplesToPurge;
samplesToPurge = 0;
} else {
samplesToPurge -= samplesAvailable;
mCurrentBufferPointer = mCurrentBuffer.length;
}
} else {
samplesToPurge = 0;
}
}
}
/**
* Takes a calculated DFT results set, reformats the data, and sends it out to all registered
* listeners.
*/
private void dispatch(float[] results) {
Iterator<DFTResultsConverter> it = mListeners.iterator();
while (it.hasNext()) {
it.next().receive(results);
}
}
public void addConverter(DFTResultsConverter listener) {
mListeners.add(listener);
}
public void removeConverter(DFTResultsConverter listener) {
mListeners.remove(listener);
}
private class DFTCalculationTask implements Runnable {
@Override
public void run() {
try {
/* Only run if we're not currently running */
if (mRunning.compareAndSet(false, true)) {
checkFFTSize();
calculate();
mRunning.set(false);
}
} catch (Exception e) {
mLog.error("error during dft processor calculation task", e);
}
}
}
/**
* Checks for a queued FFT width change request and applies it. This method will only be accessed
* by the scheduled executor that gains access to run a calculate method, thus providing thread
* safety.
*/
private void checkFFTSize() {
if (mNewDFTSize.getSize() != mDFTSize.getSize()) {
mDFTSize = mNewDFTSize;
calculateConsumptionRate();
setWindowType(mWindowType);
if (mSampleType == SampleType.COMPLEX) {
mPreviousFrame = new float[mDFTSize.getSize() * 2];
} else {
mPreviousFrame = new float[mDFTSize.getSize()];
}
mFFT = new FloatFFT_1D(mDFTSize.getSize());
}
}
public void clearBuffer() {
mQueue.clear();
}
@Override
public void frequencyChanged(FrequencyChangeEvent event) {
switch (event.getEvent()) {
case SAMPLE_RATE_CHANGE_NOTIFICATION:
mSampleRate = event.getValue().intValue();
calculateConsumptionRate();
break;
default:
break;
}
}
/** */
private void calculateConsumptionRate() {
mNewFloatResidual = 0.0f;
mNewFloatsPerFrame =
((float) mSampleRate / (float) mFrameRate)
* (mSampleType == SampleType.COMPLEX ? 2.0f : 1.0f);
mFFTFloatsPerFrame =
(mSampleType == SampleType.COMPLEX ? mDFTSize.getSize() * 2 : mDFTSize.getSize());
}
}
