plectrum

commit 268eee3e35fd397b6a590ccf06edede73acdfe7a
parent 7923745301c1d78a22fdc34b6bcc6cb3633c8294
Author: gstraube <gstraube@mailbox.org>
Date:   Mon, 17 Jul 2017 18:47:43 +0200

Calculate average pitch difference

Diffstat:
M
app/src/main/java/com/github/cythara/MainActivity.java
 | 
25
+++++++++++++++++++------
A
app/src/main/java/com/github/cythara/Sampler.java
 | 
58
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

2 files changed, 77 insertions(+), 6 deletions(-)
diff --git a/app/src/main/java/com/github/cythara/MainActivity.java b/app/src/main/java/com/github/cythara/MainActivity.java
@@ -7,6 +7,8 @@ import android.support.v7.app.AppCompatActivity;
 import android.util.Log;
 
 import java.lang.ref.WeakReference;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Locale;
 
 import be.tarsos.dsp.AudioDispatcher;
@@ -25,6 +27,8 @@ public class MainActivity extends AppCompatActivity {
     private static final int BUFFER_SIZE = FastYin.DEFAULT_BUFFER_SIZE;
     private static final int OVERLAP = FastYin.DEFAULT_OVERLAP;
     private static final double MAX_DEVIATION = 50;
+    private static final int MIN_ITEMS_COUNT = 5;
+    private static List<PitchDifference> pitchDifferences = new ArrayList<>();
 
     final Handler updateHandler = new UpdateHandler(this);
     final PitchListener pitchListener = new PitchListener(this);
@@ -66,14 +70,23 @@ public class MainActivity extends AppCompatActivity {
                                         pitchDifference.closest.name(),
                                         pitchDifference.deviation, pitch);
 
-                                Message message = new Message();
-                                Bundle bundle = new Bundle();
-                                bundle.putParcelable("pitchDiff", pitchDifference);
-                                message.setData(bundle);
+                                pitchDifferences.add(pitchDifference);
 
-                                activity.updateHandler.sendMessage(message);
+                                if (pitchDifferences.size() >= MIN_ITEMS_COUNT) {
+                                    PitchDifference average =
+                                            Sampler.calculateAverageDifference(pitchDifferences);
 
-                                Log.d("com.github.cythara", msg);
+                                    Message message = new Message();
+                                    Bundle bundle = new Bundle();
+                                    bundle.putParcelable("pitchDiff", average);
+                                    message.setData(bundle);
+
+                                    activity.updateHandler.sendMessage(message);
+
+                                    pitchDifferences.clear();
+
+                                    Log.d("com.github.cythara", msg);
+                                }
                             }
                         }
                     }
diff --git a/app/src/main/java/com/github/cythara/Sampler.java b/app/src/main/java/com/github/cythara/Sampler.java
@@ -0,0 +1,58 @@
+package com.github.cythara;
+
+import android.support.annotation.Nullable;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+class Sampler {
+
+    static PitchDifference calculateAverageDifference(List<PitchDifference> samples) {
+        Note mostFrequentNote = extractMostFrequentNote(samples);
+
+        double deviationSum = 0;
+        int sameNoteCount = 0;
+        for (PitchDifference pitchDifference : samples) {
+            if (pitchDifference.closest == mostFrequentNote) {
+                deviationSum += pitchDifference.deviation;
+                sameNoteCount++;
+            }
+        }
+
+        if (sameNoteCount > 0) {
+            double averageDeviation = deviationSum / sameNoteCount;
+
+            return new PitchDifference(mostFrequentNote, averageDeviation);
+        }
+
+        return null;
+    }
+
+    @Nullable
+    private static Note extractMostFrequentNote(List<PitchDifference> samples) {
+        Map<Note, Integer> noteFrequencies = new HashMap<>();
+
+        for (PitchDifference pitchDifference : samples) {
+            Note closest = pitchDifference.closest;
+            if (noteFrequencies.containsKey(closest)) {
+                Integer count = noteFrequencies.get(closest);
+                noteFrequencies.put(closest, count + 1);
+            } else {
+                noteFrequencies.put(closest, 1);
+            }
+        }
+
+        Note mostFrequentNote = null;
+        int mostOccurrences = 0;
+        for (Note note : noteFrequencies.keySet()) {
+            Integer occurrences = noteFrequencies.get(note);
+            if (occurrences > mostOccurrences) {
+                mostFrequentNote = note;
+                mostOccurrences = occurrences;
+            }
+        }
+
+        return mostFrequentNote;
+    }
+}