deprecate p5.SoundFile.processPeaks (#584)

this offline approach to processing peaks didn't work very well and makes the codebase confusing!

Author: therewasaguy

examples/peakDetection_offline/index.html

@@ -16,161 +16,6 @@ var _createCounterBuffer = function (buffer) {
   return audioBuf;
 };
 
-// process peaks
-class Peak {
-  constructor(amp, i) {
-    this.sampleIndex = i;
-    this.amplitude = amp;
-    this.tempos = [];
-    this.intervals = [];
-  }
-}
-
-// 1. for processPeaks() Function to identify peaks above a threshold
-// returns an array of peak indexes as frames (samples) of the original soundfile
-function getPeaksAtThreshold(data, threshold) {
-  var peaksObj = {};
-  var length = data.length;
-
-  for (var i = 0; i < length; i++) {
-    if (data[i] > threshold) {
-      var amp = data[i];
-      var peak = new Peak(amp, i);
-      peaksObj[i] = peak;
-      // Skip forward ~ 1/8s to get past this peak.
-      i += 6000;
-    }
-    i++;
-  }
-  return peaksObj;
-}
-
-// 2. for processPeaks()
-function countIntervalsBetweenNearbyPeaks(peaksObj) {
-  var intervalCounts = [];
-  var peaksArray = Object.keys(peaksObj).sort();
-
-  for (var index = 0; index < peaksArray.length; index++) {
-    // find intervals in comparison to nearby peaks
-    for (var i = 0; i < 10; i++) {
-      var startPeak = peaksObj[peaksArray[index]];
-      var endPeak = peaksObj[peaksArray[index + i]];
-
-      if (startPeak && endPeak) {
-        var startPos = startPeak.sampleIndex;
-        var endPos = endPeak.sampleIndex;
-        var interval = endPos - startPos;
-
-        // add a sample interval to the startPeak in the allPeaks array
-        if (interval > 0) {
-          startPeak.intervals.push(interval);
-        }
-
-        // tally the intervals and return interval counts
-        var foundInterval = intervalCounts.some(function (intervalCount) {
-          if (intervalCount.interval === interval) {
-            intervalCount.count++;
-            return intervalCount;
-          }
-        });
-
-        // store with JSON like formatting
-        if (!foundInterval) {
-          intervalCounts.push({
-            interval: interval,
-            count: 1,
-          });
-        }
-      }
-    }
-  }
-
-  return intervalCounts;
-}
-
-// 3. for processPeaks --> find tempo
-function groupNeighborsByTempo(intervalCounts, sampleRate) {
-  var tempoCounts = [];
-
-  intervalCounts.forEach(function (intervalCount) {
-    try {
-      // Convert an interval to tempo
-      var theoreticalTempo = Math.abs(
-        60 / (intervalCount.interval / sampleRate)
-      );
-
-      theoreticalTempo = mapTempo(theoreticalTempo);
-
-      var foundTempo = tempoCounts.some(function (tempoCount) {
-        if (tempoCount.tempo === theoreticalTempo)
-          return (tempoCount.count += intervalCount.count);
-      });
-      if (!foundTempo) {
-        if (isNaN(theoreticalTempo)) {
-          return;
-        }
-        tempoCounts.push({
-          tempo: Math.round(theoreticalTempo),
-          count: intervalCount.count,
-        });
-      }
-    } catch (e) {
-      throw e;
-    }
-  });
-
-  return tempoCounts;
-}
-
-// 4. for processPeaks - get peaks at top tempo
-function getPeaksAtTopTempo(peaksObj, tempo, sampleRate, bpmVariance) {
-  var peaksAtTopTempo = [];
-  var peaksArray = Object.keys(peaksObj).sort();
-
-  // TO DO: filter out peaks that have the tempo and return
-  for (var i = 0; i < peaksArray.length; i++) {
-    var key = peaksArray[i];
-    var peak = peaksObj[key];
-
-    for (var j = 0; j < peak.intervals.length; j++) {
-      var intervalBPM = Math.round(
-        Math.abs(60 / (peak.intervals[j] / sampleRate))
-      );
-
-      intervalBPM = mapTempo(intervalBPM);
-
-      if (Math.abs(intervalBPM - tempo) < bpmVariance) {
-        // convert sampleIndex to seconds
-        peaksAtTopTempo.push(peak.sampleIndex / sampleRate);
-      }
-    }
-  }
-
-  // filter out peaks that are very close to each other
-  peaksAtTopTempo = peaksAtTopTempo.filter(function (peakTime, index, arr) {
-    var dif = arr[index + 1] - peakTime;
-    if (dif > 0.01) {
-      return true;
-    }
-  });
-
-  return peaksAtTopTempo;
-}
-
-// helper function for processPeaks
-function mapTempo(theoreticalTempo) {
-  // these scenarios create infinite while loop
-  if (!isFinite(theoreticalTempo) || theoreticalTempo === 0) {
-    return;
-  }
-
-  // Adjust the tempo to fit within the 90-180 BPM range
-  while (theoreticalTempo < 90) theoreticalTempo *= 2;
-  while (theoreticalTempo > 180 && theoreticalTempo > 90) theoreticalTempo /= 2;
-
-  return theoreticalTempo;
-}
-
 /*** SCHEDULE EVENTS ***/
 
 // Cue inspired by JavaScript setTimeout, and the
@@ -1487,101 +1332,8 @@ class SoundFile {
     return bufferSourceNode;
   }
 
-  /**
-   *  processPeaks returns an array of timestamps where it thinks there is a beat.
-   *
-   *  This is an asynchronous function that processes the soundfile in an offline audio context,
-   *  and sends the results to your callback function.
-   *
-   *  The process involves running the soundfile through a lowpass filter, and finding all of the
-   *  peaks above the initial threshold. If the total number of peaks are below the minimum number of peaks,
-   *  it decreases the threshold and re-runs the analysis until either minPeaks or minThreshold are reached.
-   *
-   *  @method  processPeaks
-   *  @for p5.SoundFile
-   *  @param  {Function} callback       a function to call once this data is returned
-   *  @param  {Number}   [initThreshold] initial threshold defaults to 0.9
-   *  @param  {Number}   [minThreshold]   minimum threshold defaults to 0.22
-   *  @param  {Number}   [minPeaks]       minimum number of peaks defaults to 200
-   *  @return {Array}                  Array of timestamped peaks
-   */
   processPeaks(callback, _initThreshold, _minThreshold, _minPeaks) {
-    var self = this;
-    var bufLen = this.buffer.length;
-    var sampleRate = this.buffer.sampleRate;
-    var buffer = this.buffer;
-    var allPeaks = [];
-
-    var initialThreshold = _initThreshold || 0.9,
-      threshold = initialThreshold,
-      minThreshold = _minThreshold || 0.22,
-      minPeaks = _minPeaks || 200;
-
-    // Create offline context
-    var offlineContext = new window.OfflineAudioContext(1, bufLen, sampleRate);
-
-    // create buffer source
-    var source = offlineContext.createBufferSource();
-    source.buffer = buffer;
-
-    // Create filter. TO DO: allow custom setting of filter
-    var filter = offlineContext.createBiquadFilter();
-    filter.type = 'lowpass';
-    source.connect(filter);
-    filter.connect(offlineContext.destination);
-
-    // start playing at time:0
-    source.start(0);
-    offlineContext.startRendering(); // Render the song
-
-    // act on the result
-    offlineContext.oncomplete = function (e) {
-      if (!self.panner) return;
-      var filteredBuffer = e.renderedBuffer;
-      var bufferData = filteredBuffer.getChannelData(0);
-
-      // step 1:
-      // create Peak instances, add them to array, with strength and sampleIndex
-      do {
-        allPeaks = getPeaksAtThreshold(bufferData, threshold);
-        threshold -= 0.005;
-      } while (
-        Object.keys(allPeaks).length < minPeaks &&
-        threshold >= minThreshold
-      );
-
-      // step 2:
-      // find intervals for each peak in the sampleIndex, add tempos array
-      var intervalCounts = countIntervalsBetweenNearbyPeaks(allPeaks);
-
-      // step 3: find top tempos
-      var groups = groupNeighborsByTempo(
-        intervalCounts,
-        filteredBuffer.sampleRate
-      );
-
-      // sort top intervals
-      var topTempos = groups
-        .sort(function (intA, intB) {
-          return intB.count - intA.count;
-        })
-        .splice(0, 5);
-
-      // set this SoundFile's tempo to the top tempo ??
-      this.tempo = topTempos[0].tempo;
-
-      // step 4:
-      // new array of peaks at top tempo within a bpmVariance
-      var bpmVariance = 5;
-      var tempoPeaks = getPeaksAtTopTempo(
-        allPeaks,
-        topTempos[0].tempo,
-        filteredBuffer.sampleRate,
-        bpmVariance
-      );
-
-      callback(tempoPeaks);
-    };
+    console.warn('processPeaks is deprecated');
   }
 
   /**