plectrum

Granulator.java (9722B)

---

 package be.tarsos.dsp.granulator;
 
 
 import java.util.ArrayList;
 import java.util.Arrays;
 
 import be.tarsos.dsp.AudioEvent;
 import be.tarsos.dsp.AudioProcessor;
 
 /**
  * Granulator plays back samples using granular synthesis. 
  * Methods can be used to control playback rate, pitch, grain size,
  *  grain interval and grain randomness and position (this last case assumes that the playback rate is zero). 
  * 
  * 
  * 
  * @author ollie
  * @author Joren
  */
 public class Granulator implements AudioProcessor  {
 
 	public static final float ADAPTIVE_INTERP_LOW_THRESH = 0.5f;
 	public static final float ADAPTIVE_INTERP_HIGH_THRESH = 2.5f;
 	
 	/** The position in milliseconds. */
 	protected double position;
 	
 	/**
 	 * The millisecond position increment per sample. Calculated from the ratio
 	 * of the {@link AudioContext}'s sample rate and the {@link Sample}'s sample
 	 * rate.
 	 */
 	private double positionIncrement;
 	
 	
 	private float grainInterval;
 	private float grainSize;
 	private float grainRandomness;
 	
 	/** The time in milliseconds since the last grain was activated. */
 	private float timeSinceLastGrain;
 
 	/** The length of one sample in milliseconds. */
 	private double msPerSample;
 
 	/** The pitch, bound to the pitch envelope. */
 	private float pitchFactor;
 	
 	/** The pitch, bound to the pitch envelope. */
 	private float timeStretchFactor;
 
 	/** The list of current grains. */
 	private ArrayList<Grain> grains;
 
 	/** A list of free grains. */
 	private ArrayList<Grain> freeGrains;
 
 	/** A list of dead grains. */
 	private ArrayList<Grain> deadGrains;
 	
 	/** The interpolation type. */
 	//protected InterpolationType interpolationType;
 
 	/** The window used by grains. */
 	private final float[] window;
 	
 		
 	private final float[] audioBuffer;
 	private int audioBufferWatermark;
 	
 	private final float[] outputBuffer;
 	
 
 	/**
 	 * Instantiates a new GranularSamplePlayer.
 	 * 
 	 * @param sampleRate the sample rate.
 	 * @param bufferSize the size of an output buffer.
 	 */
 	public Granulator(float sampleRate,int bufferSize) {
 		grains = new ArrayList<Grain>();
 		freeGrains = new ArrayList<Grain>();
 		deadGrains = new ArrayList<Grain>();
 		
 		audioBuffer = new float[(int) (12*60*sampleRate)];//max 12 minutes of audio
 		audioBufferWatermark = 0;
 		
 		pitchFactor = 1.0f;
 		
 		grainInterval = 40.0f;
 		grainSize = 100.0f;
 		grainRandomness = 0.1f;
 		
 		window = new be.tarsos.dsp.util.fft.CosineWindow().generateCurve(bufferSize);
 		outputBuffer = new float[bufferSize];
 		
 		msPerSample = 1000.0f/sampleRate;
 		
 		positionIncrement = msPerSample;
 	}
 
 		
 	public void start() {
 		timeSinceLastGrain = 0;
 	}
 	
 	
 	/** Flag to indicate special case for the first grain. */
 	private boolean firstGrain = true;
 
 	/** Special case method for playing first grain. */
 	private void firstGrain() {
 		if(firstGrain) {
 			Grain g = new Grain();
 			g.position = position;
 			g.age = grainSize / 4f;
 			g.grainSize = grainSize;
 			
 			grains.add(g);
 			firstGrain = false;
 			timeSinceLastGrain = grainInterval / 2f;
 		}
 	}
 
 	@Override
 	public boolean process(AudioEvent audioEvent) {
 		System.arraycopy(audioEvent.getFloatBuffer(), 0, audioBuffer,
 				audioBufferWatermark, audioEvent.getBufferSize());
 		audioBufferWatermark += audioEvent.getBufferSize();
 
 		// grains.clear();
 		// position = audioEvent.getTimeStamp()*1000 - 5000;
 
 		// reset output
 		Arrays.fill(outputBuffer, 0);
 
 		firstGrain();
 
 		int bufferSize = audioEvent.getBufferSize();
 
 		// now loop through the buffer
 		for (int i = 0; i < bufferSize; i++) {
 			// determine if we need a new grain
 			if (timeSinceLastGrain > grainInterval) {
 				Grain g = null;
 				if (freeGrains.size() > 0) {
 					g = freeGrains.get(0);
 					freeGrains.remove(0);
 				} else {
 					g = new Grain();
 				}
 				g.reset(grainSize, grainRandomness, position,timeStretchFactor,pitchFactor);
 				grains.add(g);
 				timeSinceLastGrain = 0f;
 				//System.out.println(grains.size());
 			}
 
 			// gather the output from each grain
 			for (int gi = 0; gi < grains.size(); gi++) {
 				Grain g = grains.get(gi);
 				// calculate value of grain window
 				float windowScale = getValueFraction((float) (g.age / g.grainSize));
 				// get position in sample for this grain
 				// get the frame for this grain
 
 				double sampleValue;
 				getFrameLinear(g.position);
 				if (pitchFactor > ADAPTIVE_INTERP_HIGH_THRESH) {
 					sampleValue = getFrameNoInterp(g.position);
 				} else if (pitchFactor > ADAPTIVE_INTERP_LOW_THRESH) {
 					sampleValue = getFrameLinear(g.position);
 				} else {
 					sampleValue = getFrameCubic(g.position);
 				}
 				sampleValue = sampleValue * windowScale;
 				outputBuffer[i] += (float) sampleValue;
 			}
 			// increment time
 			position += positionIncrement * timeStretchFactor;
 
 			for (int gi = 0; gi < grains.size(); gi++) {
 				Grain g = grains.get(gi);
 				calculateNextGrainPosition(g);
 			}
 			// increment timeSinceLastGrain
 			timeSinceLastGrain += msPerSample;
 			// finally, see if any grains are dead
 			for (int gi = 0; gi < grains.size(); gi++) {
 				Grain g = grains.get(gi);
 				if (g.age > g.grainSize) {
 					freeGrains.add(g);
 					deadGrains.add(g);
 				}
 			}
 			for (int gi = 0; gi < deadGrains.size(); gi++) {
 				Grain g = deadGrains.get(gi);
 				grains.remove(g);
 			}
 			deadGrains.clear();
 		}
 		audioEvent.setFloatBuffer(outputBuffer);
 
 		return true;
 	}
 	
 
 	/**
 	 * Retrieves a frame of audio using linear interpolation. If the frame is
 	 * not in the sample range then zeros are returned.
 	 * 
 	 * @param posInMS
 	 *            The frame to read -- can be fractional (e.g., 4.4).
 	 * @param result
 	 *            The framedata to fill.
 	 */
 	public double getFrameLinear(double posInMS) {
 		double result = 0.0;
 		double sampleNumber = msToSamples(posInMS);
 		int sampleNumberFloor = (int) Math.floor(sampleNumber);
 		if (sampleNumberFloor > 0 && sampleNumberFloor < audioBufferWatermark) {
 			double sampleNumberFraction = sampleNumber - sampleNumberFloor;
 			if (sampleNumberFloor == audioBufferWatermark - 1) {
 				result = audioBuffer[sampleNumberFloor];
 			} else {
 				// linear interpolation
 				double current = audioBuffer[sampleNumberFloor];
 				double next = audioBuffer[sampleNumberFloor];
 				result = (float) ((1 - sampleNumberFraction) * current + sampleNumberFraction * next);
 			} 
 		}
 		return result;
 	}
 	
 	/**
 	 * Retrieves a frame of audio using no interpolation. If the frame is not in
 	 * the sample range then zeros are returned.
 	 * 
 	 * @param posInMS
 	 *            The frame to read -- will take the last frame before this one.
 	 *
 	 */
 	public float getFrameNoInterp(double posInMS) {
 		double frame = msToSamples(posInMS);
 		int frame_floor = (int) Math.floor(frame);
 		return audioBuffer[frame_floor];
 	}
 	
 	/**
 	 * Retrieves a frame of audio using cubic interpolation. If the frame is not
 	 * in the sample range then zeros are returned.
 	 * 
 	 * @param posInMS
 	 *            The frame to read -- can be fractional (e.g., 4.4).
 	 */
 	public float getFrameCubic(double posInMS) {
 		float frame = (float) msToSamples(posInMS);
 		float result = 0.0f;
 		float a0, a1, a2, a3, mu2;
 		float ym1, y0, y1, y2;
 	
 		int realCurrentSample = (int) Math.floor(frame);
 		float fractionOffset = (float) (frame - realCurrentSample);
 
 		if (realCurrentSample >= 0 && realCurrentSample < (audioBufferWatermark - 1)) {
 			realCurrentSample--;
 			if (realCurrentSample < 0) {
 				ym1 = audioBuffer[0];
 				realCurrentSample = 0;
 			} else {
 				ym1 = audioBuffer[realCurrentSample++];
 			}
 			y0 = audioBuffer[realCurrentSample++];
 			if (realCurrentSample >= audioBufferWatermark) {
 				y1 = audioBuffer[audioBufferWatermark-1]; // ??
 			} else {
 				y1 = audioBuffer[realCurrentSample++];
 			}
 			if (realCurrentSample >= audioBufferWatermark) {
 				y2 = audioBuffer[audioBufferWatermark-1];
 			} else {
 				y2 = audioBuffer[realCurrentSample++];
 			}
 			mu2 = fractionOffset * fractionOffset;
 			a0 = y2 - y1 - ym1 + y0;
 			a1 = ym1 - y0 - a0;
 			a2 = y1 - ym1;
 			a3 = y0;
 			result = a0 * fractionOffset * mu2 + a1 * mu2 + a2 * fractionOffset + a3;
 		}
 		return result;
 	}
 	
 	
 	private double msToSamples(double posInMs){
 		return (posInMs) / msPerSample;
 	}
 
 	@Override
 	public void processingFinished() {
 		
 	}
 	
 	/**
 	 * Returns the value of the buffer at the given fraction along its length (0 = start, 1 = end). Uses linear interpolation.
 	 * 
 	 * @param fraction the point along the buffer to inspect. 
 	 * 
 	 * @return the value at that point.
 	 */
 	public float getValueFraction(float fraction) {
 		float posInBuf = fraction * window.length;
 		int lowerIndex = (int)posInBuf;
 		float offset = posInBuf - lowerIndex;
 		int upperIndex = (lowerIndex + 1) % window.length;
 		return (1 - offset) * window[lowerIndex] + offset * window[upperIndex];
 	}
 
 	/**
 	 * Calculate next position for the given Grain.
 	 * 
 	 * @param g the Grain.
 	 */
 	private void calculateNextGrainPosition(Grain g) {
 		int direction = timeStretchFactor >= 0 ? 1 : -1;	//this is a bit odd in the case when controlling grain from positionEnvelope
 		g.age += msPerSample;
 		g.position += direction * positionIncrement * pitchFactor;	
 	}
 
 	public void setTimestretchFactor(float currentFactor) {
 		timeStretchFactor = currentFactor;
 	}
 
 	public void setPitchShiftFactor(float currentFactor) {
 		pitchFactor = currentFactor;
 	}
 
 
 
 	public void setGrainInterval(int grainInterval) {
 		this.grainInterval = grainInterval;
 	}
 
 
 
 	public void setGrainSize(int grainSize) {
 		this.grainSize = grainSize;
 		
 	}
 
 	public void setGrainRandomness(float grainRandomness) {
 		this.grainRandomness = grainRandomness;
 	}
 
 
 
 	/**
 	 * @param position in seconds
 	 */
 	public void setPosition(float position) {
 		this.position = position * 1000;
 	}
 }