Android Open Source - Spectograph Spectogram

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License

The source code is released under:

Copyright (c) 2013 Salman aljammaz Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the So...

Java Source Code

package net.x65.spectograph;
//w ww.j av  a 2 s .  c  o  m
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import java.util.ArrayList;
import android.media.audiofx.Visualizer;

public class Spectogram
extends SurfaceView
implements SurfaceHolder.Callback {
  private static final String TAG = Spectogram.class.getSimpleName();

  ArrayList<int[]> hist;
  private DrawThread worker = new DrawThread(this, getHolder());
  
  public Spectogram(Context context, AttributeSet attrs) {
    super(context, attrs);
    
    this.hist = ((SpectographApp)((Activity) context).getApplication()).hist;
    
    getHolder().addCallback(this);
    setFocusable(true);

    //rec.startRecording();
    v.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
    v.setEnabled(true);
    
    Log.d(TAG, "View initialised");
  }

  public void release() {
  }
  
  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
  }
 
  @Override
   public void surfaceCreated(SurfaceHolder holder) {
    Log.d(TAG, "surfaceCreated");
    worker.start();
  }
 
  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {
    Log.d(TAG, "surfaceDestroyed");
    worker.interrupt();
    while (true) {
      try {
        worker.join();
        return;
      } catch (InterruptedException e) {
      }
    }

  }
    
  Paint fg = new Paint();
  Bitmap mCanvasBitmap;
  Canvas mCanvas;
  
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    mCanvasBitmap = Bitmap.createBitmap(w, h, Config.ARGB_8888);
    mCanvas = new Canvas(mCanvasBitmap);
    mCanvas.drawColor(0xff000000);
  }

  double maxAmp = 1;
  void drawGraph() {
    if (hist.size() == 0) {
      return;
    }
    
    int end = hist.size();
    
    int start = end - getWidth();
    if (start < 0) {
      start = 0;
    }
    
    for (int cur = start; cur < end ; cur++) {
      //TODO scaling here
      int x = hist.size() - cur;
      int[] notes = hist.get(cur);
      
      
      maxAmp /= 2;
      for (int i = 0; i < notes.length; i++) {
        if (notes[i] > maxAmp) {
          maxAmp = notes[i];
        }
      }
      
      if (maxAmp > 0) {
      }
      
      // TODO proper colour scaling
      float cy = 0;
      for (int i = 0; i < notes.length; i++) {
        float y = (float) (getHeight() * i) / notes.length;
      
        int color = 0xff;
        color &= 255 * (int)(((double)notes[i])/maxAmp);
      
        fg.setColor(0xff000000 + (color<<16));
        
        mCanvas.drawLine(x, cy, x, y, fg);
        cy = y;
      }
    }
  }
  
  void drawLines() {
    for (int i = 0; i < 12*7; i += 1) {
      if (i%12 == 0) {
        fg.setColor(0x8fffffff);
      } else {
        fg.setColor(0x3fffffff);
      }
    
      float y = (float) (getHeight() * i) / (12*7);
      mCanvas.drawLine(0, y, getWidth(), y, fg);
    }
  }
  
  void render(Canvas c) {
    drawGraph();
    drawLines();
    c.drawBitmap(mCanvasBitmap, new Matrix(), null);
  }
  
  static int sampleRate = 44100;
  static int captureSize = 1024; //8192*2;
  static int tet = 12;
  static double baseFreq = 32.7;
  
  //AudioRecord rec = new AudioRecord(MediaRecorder.AudioSource.DEFAULT,
  //  sampleRate,
  //  AudioFormat.CHANNEL_CONFIGURATION_MONO,
  //  AudioFormat.ENCODING_PCM_16BIT,
  //  captureSize * 2);

  Visualizer v = new Visualizer(0);

  FFT fft = new FFT(captureSize);
  byte[] audioData = new byte[captureSize];
  double[] waveform = new double[captureSize];
  byte[] freqs = new byte[captureSize];
  void update() {
    //rec.read(audioData, 0, captureSize);
    //for (int i = 0; i < audioData.length; i++) {
    //  waveform[i] = audioData[i];
    //}
    //fft.fft(waveform, freqs);
    
    v.getFft(freqs);
    
    
    int[] notes = new int[tet*7];
    
    for (int k = 0; k < notes.length; k++) {
      double f = freqAtNote(k);
      double fNext = freqAtNote(k+1);
      
      int start = indexAtFreq(f)+1;
      int end = indexAtFreq(fNext)+1;
      int len = end-start;
      int mag = 0;
      
      for (int j = start; j < end; j+=2) {
        mag += (freqs[j] * freqs[j] + freqs[j+1] * freqs[j+1] ) / len;
      }
      notes[k] = mag;
      
      /*  if (hist.size() % 30 == 0) Log.d(TAG, "note:" + k +
                      " start:" + start +
                      " end:" + end +
                      " mag:" + mag +
                      " f:" + f
                      );*/
      
    }
    
    hist.add(notes);
  }
  
  static int indexAtFreq(double f) {
     // possible off by 1 error here
    return (int) (f * captureSize / sampleRate);
  }
  
  static double freqAtIndex(int i) {
    return i * sampleRate / captureSize;
  }
  
  static double freqAtNote(int n) {
    return baseFreq * Math.pow(2, (double)n/tet);
  }
}

Java Source Code List

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