Add an AudioTrack based audio output stream.

media/base/android/java/src/org/chromium/media/AudioTrackOutputStream.java

Index: media/base/android/java/src/org/chromium/media/AudioTrackOutputStream.java
diff --git a/media/base/android/java/src/org/chromium/media/AudioTrackOutputStream.java b/media/base/android/java/src/org/chromium/media/AudioTrackOutputStream.java
new file mode 100644
index 0000000000000000000000000000000000000000..54045e4bcda85d42eeb65e229e589b775c2eb0fc
--- /dev/null
+++ b/media/base/android/java/src/org/chromium/media/AudioTrackOutputStream.java
@@ -0,0 +1,142 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.media;
+
+import android.annotation.TargetApi;
+import android.media.AudioFormat;
+import android.media.AudioManager;
+import android.media.AudioTrack;
+
+import org.chromium.base.Log;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.base.annotations.JNINamespace;
+
+import java.nio.ByteBuffer;
+
+@JNINamespace("media")
+class AudioTrackOutputStream implements AudioTrack.OnPlaybackPositionUpdateListener {
+    private static final String TAG = "cr.media";
+
+    private AudioTrack mAudioTrack;
+    private long mNativeAudioTrackOutputStream;
+    private int mBufferSizeInBytes;
+    private ByteBuffer mAudioBuffer;
+    private long mPeriodCount;
+
+    @CalledByNative
+    private static AudioTrackOutputStream create() {
+        return new AudioTrackOutputStream();
+    }
+
+    @CalledByNative
+    private boolean open(int channelCount, int sampleRate, int sampleFormat, int framesPerBuffer) {
+        assert (channelCount == 1 || channelCount == 2);
+        assert (sampleFormat == AudioFormat.ENCODING_PCM_16BIT || sampleFormat == AudioFormat.ENCODING_PCM_FLOAT);
+
+        int bytesPerSample = sampleFormat == AudioFormat.ENCODING_PCM_16BIT ? 2 : 4;
+        mBufferSizeInBytes = framesPerBuffer * channelCount * bytesPerSample;
+        int allocatedBufferSize = (int)(mBufferSizeInBytes * 3);
+        allocatedBufferSize += allocatedBufferSize % (channelCount * bytesPerSample);
+
+        // Size the playout buffer at 1.5 times the requested size; this allows
+        // us to refill at the halfway mark and have room to spare.
+        try {
+            mAudioTrack = new AudioTrack(
+                AudioManager.STREAM_MUSIC, sampleRate,
+                channelCount == 1 ? AudioFormat.CHANNEL_OUT_MONO
+                                  : AudioFormat.CHANNEL_OUT_STEREO,
+                sampleFormat, allocatedBufferSize, AudioTrack.MODE_STREAM);
+        } catch (IllegalArgumentException ile) {
+            Log.e(TAG, "Exception creating AudioTrack for playback: ", ile);
+            return false;
+        }
+
+        if (mAudioTrack.getState() == AudioTrack.STATE_UNINITIALIZED) {
+          Log.e(TAG, "Failed to create AudioTrack...");
+          return false;
+        }
+
+        // Setup periodic callbacks to deliver audio data.
+        mAudioTrack.setPlaybackPositionUpdateListener(this);
+        if (mAudioTrack.setPositionNotificationPeriod(framesPerBuffer) != AudioTrack.SUCCESS) {
+            Log.e(TAG, "Failed to set AudioTrack position listener.");
+            return false;
+        }
+
+        return true;
+    }
+
+    @CalledByNative
+    private void start(long nativeAudioTrackOutputStream) {
+        Log.w(TAG, "AudioTrackOutputStream.start()");
+        mPeriodCount = 0;
+        mNativeAudioTrackOutputStream = nativeAudioTrackOutputStream;
+
+        // Prime the buffer with silence.
+        mAudioBuffer = ByteBuffer.allocateDirect(mBufferSizeInBytes);
+        int bytesWritten = 0;
+        do {
+            bytesWritten = mAudioTrack.write(mAudioBuffer.asReadOnlyBuffer(), mBufferSizeInBytes, AudioTrack.WRITE_BLOCKING);
+        } while (bytesWritten == mBufferSizeInBytes);
+        mAudioTrack.play();
+
+        //onPeriodicNotification(mAudioTrack);
+    }
+
+    @CalledByNative
+    private void stop() {
+        Log.w(TAG, "AudioTrackOutputStream.stop()");
+        mAudioTrack.pause();
+        mAudioTrack.flush();
+        mNativeAudioTrackOutputStream = 0;
+    }
+
+    @SuppressWarnings("deprecation")
+    @CalledByNative
+    private void setVolume(double volume) {
+        Log.w(TAG, "AudioTrackOutputStream.setVolume()");
+        // Chrome sends the volume in the range [0, 1.0], whereas Android
+        // expects the volume to be within [0, getMaxVolume()].
+        float scaledVolume = (float)(volume * mAudioTrack.getMaxVolume());
+        mAudioTrack.setStereoVolume(scaledVolume, scaledVolume);
+    }
+
+    @CalledByNative
+    private void close() {
+        Log.w(TAG, "AudioTrackOutputStream.close()");
+        if (mAudioTrack != null)
+            mAudioTrack.release();
+    }
+
+    @Override
+    public void onMarkerReached(AudioTrack track) {
+    }
+
+    @Override
+    public void onPeriodicNotification(AudioTrack track) {
+        if (mNativeAudioTrackOutputStream == 0)
+            return;
+        // // Our period is half the requested size and our buffer size is 1.5
+        // // times the requested size, so skip every other interval such that we
+        // // have enough data left for glitch free playback and enough space to
+        // // fill a full request.
+        // if (mPeriodCount++ % 2 == 1)
+        //     return;
+
+        // TODO(dalecurtis): Add delay information here.
+        // TODO(dalecurtis): Add < lollipop support.
+        //short[] nativeAudioData = nativeOnMoreData(nativeAudioTrackOutputStream, 0);
+        nativeOnMoreData(mNativeAudioTrackOutputStream, mAudioBuffer, 0);
+
+        long start = System.nanoTime();
+        mAudioTrack.write(mAudioBuffer.asReadOnlyBuffer(), mBufferSizeInBytes,
+                          AudioTrack.WRITE_NON_BLOCKING);
+        //Log.w(TAG, "Write took: " + (System.nanoTime() - start) / (1000.0 * 1000.0) + "ms");
+    }
+
+    //private native short[] nativeOnMoreDataOld(long nativeAudioTrackOutputStream, int delayInFrames);
+    private native void nativeOnMoreData(long nativeAudioTrackOutputStream, ByteBuffer audioData, int delayInFrames);
+    private native void nativeOnError(long nativeAudioTrackOutputStream);
+}