plectrum

Plectrum: instrument tuner for Android
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SoundTouchRateTransposer.java (2783B)

      1 /*
      2 *      _______                       _____   _____ _____  
      3 *     |__   __|                     |  __ \ / ____|  __ \ 
      4 *        | | __ _ _ __ ___  ___  ___| |  | | (___ | |__) |
      5 *        | |/ _` | '__/ __|/ _ \/ __| |  | |\___ \|  ___/ 
      6 *        | | (_| | |  \__ \ (_) \__ \ |__| |____) | |     
      7 *        |_|\__,_|_|  |___/\___/|___/_____/|_____/|_|     
      8 *                                                         
      9 * -------------------------------------------------------------
     10 *
     11 * TarsosDSP is developed by Joren Six at IPEM, University Ghent
     12 *  
     13 * -------------------------------------------------------------
     14 *
     15 *  Info: http://0110.be/tag/TarsosDSP
     16 *  Github: https://github.com/JorenSix/TarsosDSP
     17 *  Releases: http://0110.be/releases/TarsosDSP/
     18 *  
     19 *  TarsosDSP includes modified source code by various authors,
     20 *  for credits and info, see README.
     21 * 
     22 */
     23 
     24 package be.tarsos.dsp.resample;
     25 
     26 import be.tarsos.dsp.AudioDispatcher;
     27 import be.tarsos.dsp.AudioEvent;
     28 import be.tarsos.dsp.AudioProcessor;
     29 
     30 /**
     31  * Currently not working sample rate transposer, works only for integer factors. 
     32  * Changes sample rate by using linear interpolation.
     33  * 
     34  * Together with the time stretcher this can be used for pitch shifting.
     35  * @author Joren Six
     36  * @author Olli Parviainen
     37  */
     38 public class SoundTouchRateTransposer implements AudioProcessor {
     39 
     40 	private double rate;
     41 	int slopeCount;
     42     double prevSample;
     43     private AudioDispatcher dispatcher;
     44 
     45     public void setDispatcher(AudioDispatcher newDispatcher){
     46 		this.dispatcher = newDispatcher;
     47 	}
     48     
     49 	public SoundTouchRateTransposer(double d){
     50 		this.rate = d;
     51 	}
     52 	
     53 	@Override
     54 	public boolean process(AudioEvent audioEvent) {
     55 		int i, used;
     56 		float[] src = audioEvent.getFloatBuffer();
     57 		float[] dest = new float[(int) Math.round(audioEvent.getBufferSize() / rate)];
     58 	    used = 0;
     59 	    i = 0;
     60 
     61 	    // Process the last sample saved from the previous call first...
     62 	    while (slopeCount <= 1.0f) {
     63 	        dest[i] = (float)((1.0f - slopeCount) * prevSample + slopeCount * src[0]);
     64 	        i++;
     65 	        slopeCount += rate;
     66 	    }
     67 	    slopeCount -= 1.0f;
     68 	    end:
     69         while(true){
     70             while (slopeCount > 1.0f) {
     71                 slopeCount -= 1.0f;
     72                 used++;
     73                 if (used >= src.length - 1) 
     74                 	break end;
     75             }
     76             if(i < dest.length){
     77             	dest[i] = (float)((1.0f - slopeCount) * src[used] + slopeCount * src[used + 1]);
     78             }
     79             i++;
     80             slopeCount += rate;
     81         }
     82 	    
     83 	    //Store the last sample for the next round
     84 	    prevSample = src[src.length - 1];
     85 	    dispatcher.setStepSizeAndOverlap(dest.length, 0);
     86 	    audioEvent.setFloatBuffer(dest);
     87 		return true;
     88 	}
     89 
     90 	@Override
     91 	public void processingFinished() {
     92 
     93 	}
     94 
     95 }