Model Personalization for Digit Classifier Application

lite/examples/sound_classification/android/app/src/main/java/org/tensorflow/lite/examples/soundclassifier/AudioBuffer.java

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+package org.tensorflow.lite.examples.soundclassifier;
+
+import android.media.AudioFormat;
+import android.media.AudioRecord;
+import android.provider.MediaStore;
+import android.util.Log;
+
+import java.nio.FloatBuffer;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import kotlin.collections.ArrayDeque;
+
+public class AudioBuffer {
+
+    // TODO: What if the ring buffer is not yet fully filled before invocation?
+    private class RingBuffer {
+        private float[] buffer;
+        private int current;
+
+        RingBuffer(int size) {
+            buffer = new float[size];
+        }
+
+        public int getCapacity() {
+            return buffer.length;
+        }
+
+        public void feed(float v) {
+            buffer[current] = v;
+            current = (current + 1) % buffer.length;
+        }
+
+        public void feed(float[] data, int size) {
+            for (int i = 0; i < size; i++) {
+                feed(data[i]);
+            }
+        }
+
+        public float[] getArray() {
+            float[] output = new float[buffer.length];
+            for (int i = current; i < buffer.length; i++) {
+                output[i - current] = buffer[i];
+            }
+            for (int i = 0; i < current; i++) {
+                output[buffer.length - current + i] = buffer[i];
+            }
+            return output;
+        }
+    }
+
+    // Do we actually need it in Java here?
+    private AudioFormat audioFormat;
+    private RingBuffer ringBuffer;
+    private int ringBufferIndex = 0;
+
+    public AudioBuffer(AudioFormat audioFormat, int sampleCount) {
+        this.audioFormat = audioFormat;
+        this.ringBuffer = new RingBuffer(sampleCount);
+    }
+
+    // PCM float
+    public int feed(float[] data) {
+        return feed(data, data.length);
+    }
+
+    // TODO: what's the correct name?
+    public int feed(float[] data, int size) {
+        ringBuffer.feed(data, size);
+        return size;
+    }
+
+    // PCM int16
+    public int feed(short[] data) {
+        return feed(data, data.length);
+    }
+
+    private float pcm16ToFloat(short v) {
+        return (float) v / 32768;
+    }
+
+    public int feed(short[] data, int size) {
+        for (int i = 0; i < size; i++) {
+            ringBuffer.feed(pcm16ToFloat(data[i]));
+        }
+        return size;
+    }
+
+    // Read from AudioRecord as a helper function
+    public int feed(AudioRecord record) {
+        return feed(record, ringBuffer.getCapacity());
+    }
+
+    private int feed(AudioRecord record, float[] temporary) {
+        int readSamples = record.read(temporary, 0, temporary.length, AudioRecord.READ_BLOCKING);
+        if (readSamples > 0) {
+            feed(temporary, readSamples);
+        }
+        return readSamples;
+    }
+
+    public int feed(AudioRecord record, short[] temporary) {
+        int readSamples = record.read(temporary, 0, temporary.length, AudioRecord.READ_BLOCKING);
+        if (readSamples > 0) {
+            feed(temporary, readSamples);
+        }
+        return readSamples;
+    }
+
+    public int feed(AudioRecord record, int size) {
+//        assert record.getChannelCount() == 1;
+//        assert record.getSampleRate() == this.audioFormat.getSampleRate();
+
+        int readSamples = 0;
+        switch (record.getAudioFormat()) {
+            case AudioFormat.ENCODING_PCM_FLOAT:
+                readSamples = feed(record, new float[size]);
+                break;
+            case AudioFormat.ENCODING_PCM_16BIT:
+                readSamples = feed(record, new short[size]);
+                break;
+            default:
+                Log.e(TAG, "Unsupported AudioFormat. Requires either PCM float or PCM 16.");
+        }
+
+        // Report errors.
+        switch (readSamples) {
+            case AudioRecord.ERROR_INVALID_OPERATION:
+                Log.w(TAG, "AudioRecord.ERROR_INVALID_OPERATION");
+                break;
+            case AudioRecord.ERROR_BAD_VALUE:
+                Log.w(TAG, "AudioRecord.ERROR_BAD_VALUE");
+                break;
+            case AudioRecord.ERROR_DEAD_OBJECT:
+                Log.w(TAG, "AudioRecord.ERROR_DEAD_OBJECT");
+                break;
+            case AudioRecord.ERROR:
+                Log.w(TAG, "AudioRecord.ERROR");
+                break;
+        }
+        return readSamples;
+
+    }
+
+    public AudioFormat getAudioFormat() {
+        return audioFormat;
+    }
+
+    // TODO: Convert this to byte buffer.
+
+    // TODO: ownership
+    public FloatBuffer GetAudioBufferInFloat() {
+        FloatBuffer output = FloatBuffer.wrap(this.ringBuffer.getArray());
+        // TODO: Is this needed?
+//        output.rewind();
+        return output;
+    }
+
+    private String TAG = "AudioBuffer";
+}