plectrum

Plectrum: instrument tuner for Android
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BeatRootOnsetEventHandler.java (2885B)

      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.beatroot;
     25 
     26 import java.util.Iterator;
     27 
     28 import be.tarsos.dsp.onsets.OnsetHandler;
     29 
     30 /**
     31  * Forms a bridge between the BeatRoot beat tracking system and an
     32  * interchangeable onset detector. The beat tracker does not work in real-time.
     33  * First all onsets need to be detected. In a post-processing step a beat
     34  * estimation is done using reocurring inter onset intervals (IOI's). To return
     35  * the time of the beats an OnsetHandler is abused.
     36  * 
     37  * @author Joren Six
     38  */
     39 public class BeatRootOnsetEventHandler implements OnsetHandler {
     40 
     41 	private final EventList onsetList = new EventList();
     42 	
     43 	@Override
     44 	public void handleOnset(double time, double salience) {
     45 		double roundedTime = Math.round(time *100 )/100.0;
     46 		Event e = newEvent(roundedTime,0);
     47 		e.salience = salience;
     48 		onsetList.add(e);		
     49 	}
     50 	
     51 	
     52 	/**
     53 	 * Creates a new Event object representing an onset or beat.
     54 	 * 
     55 	 * @param time
     56 	 *            The time of the beat in seconds
     57 	 * @param beatNum
     58 	 *            The index of the beat or onset.
     59 	 * @return The Event object representing the beat or onset.
     60 	 */
     61 	private Event newEvent(double time, int beatNum) {
     62 		return new Event(time,time, time, 56, 64, beatNum, 0, 1);
     63 	}
     64 	
     65 	/**
     66 	 * Guess the beats using the populated list of onsets.
     67 	 * 
     68 	 * @param beatHandler
     69 	 *            Use this handler to get the time of the beats. The salience of
     70 	 *            the beat is not calculated: -1 is returned.
     71 	 */
     72 	public void trackBeats(OnsetHandler beatHandler){
     73 		AgentList agents = null;		
     74 		// tempo not given; use tempo induction
     75 		agents = Induction.beatInduction(onsetList);
     76 		agents.beatTrack(onsetList, -1);
     77 		Agent best = agents.bestAgent();
     78 		if (best != null) {
     79 			best.fillBeats(-1.0);
     80 			EventList beats = best.events;
     81 			Iterator<Event> eventIterator = beats.iterator();
     82 			while(eventIterator.hasNext()){
     83 				Event beat = eventIterator.next();
     84 				double time = beat.keyDown;
     85 				beatHandler.handleOnset(time, -1);
     86 			}
     87 		} else {
     88 			System.err.println("No best agent");
     89 		}
     90 	}
     91 
     92 }