Allow custom VPX output buffer renderers.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=109832096

demo_misc/vp9_opus_sw/src/main/java/com/google/android/exoplayer/demo/vp9opus/VideoPlayer.java

@@ -173,7 +173,7 @@ public class VideoPlayer extends Activity implements OnClickListener,
     TrackRenderer videoRenderer =
         new LibvpxVideoTrackRenderer(sampleSource, true, handler, this, 50);
     if (useOpenGL) {
-      player.sendMessage(videoRenderer, LibvpxVideoTrackRenderer.MSG_SET_VPX_SURFACE_VIEW,
+      player.sendMessage(videoRenderer, LibvpxVideoTrackRenderer.MSG_SET_OUTPUT_BUFFER_RENDERER,
           vpxVideoSurfaceView);
       surfaceView.setVisibility(View.GONE);
     } else {
@@ -202,7 +202,7 @@ public class VideoPlayer extends Activity implements OnClickListener,
     player.addListener(this);
     mediaController.setMediaPlayer(new PlayerControl(player));
     mediaController.setEnabled(true);
-    player.sendMessage(renderers[0], LibvpxVideoTrackRenderer.MSG_SET_VPX_SURFACE_VIEW,
+    player.sendMessage(renderers[0], LibvpxVideoTrackRenderer.MSG_SET_OUTPUT_BUFFER_RENDERER,
         vpxVideoSurfaceView);
     player.prepare(renderers);
     player.setPlayWhenReady(true);

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/LibvpxVideoTrackRenderer.java

@@ -23,8 +23,7 @@ import com.google.android.exoplayer.MediaFormatHolder;
 import com.google.android.exoplayer.SampleSource;
 import com.google.android.exoplayer.SampleSourceTrackRenderer;
 import com.google.android.exoplayer.TrackRenderer;
-import com.google.android.exoplayer.ext.vp9.VpxDecoderWrapper.InputBuffer;
+import com.google.android.exoplayer.ext.vp9.VpxDecoderWrapper.VpxInputBuffer;
-import com.google.android.exoplayer.ext.vp9.VpxDecoderWrapper.OutputBuffer;
 import com.google.android.exoplayer.util.MimeTypes;
 
 import android.graphics.Bitmap;
@@ -88,7 +87,12 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
    * should be the target {@link Surface}, or null.
    */
   public static final int MSG_SET_SURFACE = 1;
-  public static final int MSG_SET_VPX_SURFACE_VIEW = 2;
+  /**
+   * The type of a message that can be passed to an instance of this class via
+   * {@link ExoPlayer#sendMessage} or {@link ExoPlayer#blockingSendMessage}. The message object
+   * should be the target {@link VpxOutputBufferRenderer}, or null.
+   */
+  public static final int MSG_SET_OUTPUT_BUFFER_RENDERER = 2;
 
   public final CodecCounters codecCounters = new CodecCounters();
 
@@ -100,14 +104,15 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
 
   private MediaFormat format;
   private VpxDecoderWrapper decoder;
-  private InputBuffer inputBuffer;
+  private VpxInputBuffer inputBuffer;
-  private OutputBuffer outputBuffer;
+  private VpxOutputBuffer outputBuffer;
+  private VpxOutputBuffer renderedOutputBuffer;
 
   private Bitmap bitmap;
   private boolean drawnToSurface;
   private boolean renderedFirstFrame;
   private Surface surface;
-  private VpxVideoSurfaceView vpxVideoSurfaceView;
+  private VpxOutputBufferRenderer outputBufferRenderer;
   private int outputMode;
 
   private boolean inputStreamEnded;
@@ -176,7 +181,13 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
       return;
     }
     sourceIsReady = continueBufferingSource(positionUs);
+    try {
       checkForDiscontinuity(positionUs);
+    } catch (VpxDecoderException e) {
+      notifyDecoderError(e);
+      throw new ExoPlaybackException(e);
+    }
+
 
     // Try and read a format if we don't have one already.
     if (format == null && !readFormat(positionUs)) {
@@ -215,7 +226,8 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
 
     if (outputBuffer.flags == VpxDecoderWrapper.FLAG_END_OF_STREAM) {
       outputStreamEnded = true;
-      releaseOutputBuffer();
+      releaseOutputBuffer(outputBuffer);
+      outputBuffer = null;
       return;
     }
 
@@ -229,7 +241,8 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
       if (droppedFrameCount == maxDroppedFrameCountToNotify) {
         notifyAndResetDroppedFrameCount();
       }
-      releaseOutputBuffer();
+      releaseOutputBuffer(outputBuffer);
+      outputBuffer = null;
       return;
     }
 
@@ -266,18 +279,23 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
         drawnToSurface = true;
         notifyDrawnToSurface(surface);
       }
-    } else if (outputBuffer.mode == VpxDecoder.OUTPUT_MODE_YUV && vpxVideoSurfaceView != null) {
+    } else if (outputBuffer.mode == VpxDecoder.OUTPUT_MODE_YUV && outputBufferRenderer != null) {
-      vpxVideoSurfaceView.renderFrame(outputBuffer);
+      outputBufferRenderer.setOutputBuffer(outputBuffer);
     }
-    releaseOutputBuffer();
+    // Release the output buffer we rendered during the previous cycle, now that we delivered a new
-  }
+    // buffer.
-
+    releaseOutputBuffer(renderedOutputBuffer);
-  private void releaseOutputBuffer() throws VpxDecoderException {
+    renderedOutputBuffer = outputBuffer;
-    decoder.releaseOutputBuffer(outputBuffer);
     outputBuffer = null;
   }
 
-  private void renderRgbFrame(OutputBuffer outputBuffer, boolean scale) {
+  private void releaseOutputBuffer(VpxOutputBuffer buffer) throws VpxDecoderException {
+    if (buffer != null) {
+      decoder.releaseOutputBuffer(buffer);
+    }
+  }
+
+  private void renderRgbFrame(VpxOutputBuffer outputBuffer, boolean scale) {
     if (bitmap == null || bitmap.getWidth() != outputBuffer.width
         || bitmap.getHeight() != outputBuffer.height) {
       bitmap = Bitmap.createBitmap(outputBuffer.width, outputBuffer.height, Bitmap.Config.RGB_565);
@@ -332,7 +350,7 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
     return true;
   }
 
-  private void checkForDiscontinuity(long positionUs) {
+  private void checkForDiscontinuity(long positionUs) throws VpxDecoderException {
     if (decoder == null) {
       return;
     }
@@ -342,9 +360,12 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
     }
   }
 
-  private void flushDecoder() {
+  private void flushDecoder() throws VpxDecoderException {
     inputBuffer = null;
+    VpxOutputBuffer bufferToRelease = outputBuffer;
+    // Set this to null now because releaseOutputBuffer could throw an exception.
     outputBuffer = null;
+    releaseOutputBuffer(bufferToRelease);
     decoder.flush();
   }
 
@@ -417,8 +438,8 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
   public void handleMessage(int messageType, Object message) throws ExoPlaybackException {
     if (messageType == MSG_SET_SURFACE) {
       setSurface((Surface) message);
-    } else if (messageType == MSG_SET_VPX_SURFACE_VIEW) {
+    } else if (messageType == MSG_SET_OUTPUT_BUFFER_RENDERER) {
-      setVpxVideoSurfaceView((VpxVideoSurfaceView) message);
+      setOutputBufferRenderer((VpxOutputBufferRenderer) message);
     } else {
       super.handleMessage(messageType, message);
     }
@@ -429,7 +450,7 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
       return;
     }
     this.surface = surface;
-    vpxVideoSurfaceView = null;
+    outputBufferRenderer = null;
     outputMode = (surface != null) ? VpxDecoder.OUTPUT_MODE_RGB : VpxDecoder.OUTPUT_MODE_UNKNOWN;
     if (decoder != null) {
       decoder.setOutputMode(outputMode);
@@ -437,20 +458,20 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
     drawnToSurface = false;
   }
 
-  private void setVpxVideoSurfaceView(VpxVideoSurfaceView vpxVideoSurfaceView) {
+  private void setOutputBufferRenderer(VpxOutputBufferRenderer outputBufferRenderer) {
-    if (this.vpxVideoSurfaceView == vpxVideoSurfaceView) {
+    if (this.outputBufferRenderer == outputBufferRenderer) {
       return;
     }
-    this.vpxVideoSurfaceView = vpxVideoSurfaceView;
+    this.outputBufferRenderer = outputBufferRenderer;
     surface = null;
-    outputMode =
+    outputMode = (outputBufferRenderer != null)
-        (vpxVideoSurfaceView != null) ? VpxDecoder.OUTPUT_MODE_YUV : VpxDecoder.OUTPUT_MODE_UNKNOWN;
+        ? VpxDecoder.OUTPUT_MODE_YUV : VpxDecoder.OUTPUT_MODE_UNKNOWN;
     if (decoder != null) {
       decoder.setOutputMode(outputMode);
     }
   }
 
-  private void notifyIfVideoSizeChanged(final OutputBuffer outputBuffer) {
+  private void notifyIfVideoSizeChanged(final VpxOutputBuffer outputBuffer) {
     if (previousWidth == -1 || previousHeight == -1
         || previousWidth != outputBuffer.width || previousHeight != outputBuffer.height) {
       previousWidth = outputBuffer.width;

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/VpxDecoder.java

@@ -15,8 +15,6 @@
  */
 package com.google.android.exoplayer.ext.vp9;
 
-import com.google.android.exoplayer.ext.vp9.VpxDecoderWrapper.OutputBuffer;
-
 import java.nio.ByteBuffer;
 
 /**
@@ -64,7 +62,7 @@ import java.nio.ByteBuffer;
    * @return 0 on success with a frame to render. 1 on success without a frame to render.
    * @throws VpxDecoderException on decode failure.
    */
-  public int decode(ByteBuffer encoded, int size, OutputBuffer outputBuffer)
+  public int decode(ByteBuffer encoded, int size, VpxOutputBuffer outputBuffer)
       throws VpxDecoderException {
     if (vpxDecode(vpxDecContext, encoded, size) != 0) {
       throw new VpxDecoderException("libvpx decode error: " + vpxGetErrorMessage(vpxDecContext));
@@ -94,7 +92,7 @@ import java.nio.ByteBuffer;
   private native long vpxInit();
   private native long vpxClose(long context);
   private native long vpxDecode(long context, ByteBuffer encoded, int length);
-  private native int vpxGetFrame(long context, OutputBuffer outputBuffer);
+  private native int vpxGetFrame(long context, VpxOutputBuffer outputBuffer);
   private native String vpxGetErrorMessage(long context);
 
 }

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/VpxDecoderWrapper.java

@@ -28,16 +28,19 @@ import java.util.LinkedList;
   public static final int FLAG_END_OF_STREAM = 1;
 
   private static final int INPUT_BUFFER_SIZE = 768 * 1024; // Value based on cs/SoftVpx.cpp.
+  /**
+   * The total number of output buffers. {@link LibvpxVideoTrackRenderer} may hold on to 2 buffers
+   * at a time so this value should be high enough considering LibvpxVideoTrackRenderer requirement.
+   */
   private static final int NUM_BUFFERS = 16;
 
   private final Object lock;
 
-  private final LinkedList<InputBuffer> dequeuedInputBuffers;
+  private final LinkedList<VpxInputBuffer> dequeuedInputBuffers;
-  private final LinkedList<InputBuffer> queuedInputBuffers;
+  private final LinkedList<VpxInputBuffer> queuedInputBuffers;
-  private final LinkedList<OutputBuffer> queuedOutputBuffers;
+  private final LinkedList<VpxOutputBuffer> queuedOutputBuffers;
-  private final LinkedList<OutputBuffer> dequeuedOutputBuffers;
+  private final VpxInputBuffer[] availableInputBuffers;
-  private final InputBuffer[] availableInputBuffers;
+  private final VpxOutputBuffer[] availableOutputBuffers;
-  private final OutputBuffer[] availableOutputBuffers;
   private int availableInputBufferCount;
   private int availableOutputBufferCount;
 
@@ -57,14 +60,13 @@ import java.util.LinkedList;
     dequeuedInputBuffers = new LinkedList<>();
     queuedInputBuffers = new LinkedList<>();
     queuedOutputBuffers = new LinkedList<>();
-    dequeuedOutputBuffers = new LinkedList<>();
+    availableInputBuffers = new VpxInputBuffer[NUM_BUFFERS];
-    availableInputBuffers = new InputBuffer[NUM_BUFFERS];
+    availableOutputBuffers = new VpxOutputBuffer[NUM_BUFFERS];
-    availableOutputBuffers = new OutputBuffer[NUM_BUFFERS];
     availableInputBufferCount = NUM_BUFFERS;
     availableOutputBufferCount = NUM_BUFFERS;
     for (int i = 0; i < NUM_BUFFERS; i++) {
-      availableInputBuffers[i] = new InputBuffer();
+      availableInputBuffers[i] = new VpxInputBuffer();
-      availableOutputBuffers[i] = new OutputBuffer();
+      availableOutputBuffers[i] = new VpxOutputBuffer();
     }
   }
 
@@ -72,13 +74,13 @@ import java.util.LinkedList;
     this.outputMode = outputMode;
   }
 
-  public InputBuffer dequeueInputBuffer() throws VpxDecoderException {
+  public VpxInputBuffer dequeueInputBuffer() throws VpxDecoderException {
     synchronized (lock) {
       maybeThrowDecoderError();
       if (availableInputBufferCount == 0) {
         return null;
       }
-      InputBuffer inputBuffer = availableInputBuffers[--availableInputBufferCount];
+      VpxInputBuffer inputBuffer = availableInputBuffers[--availableInputBufferCount];
       inputBuffer.flags = 0;
       inputBuffer.sampleHolder.clearData();
       dequeuedInputBuffers.addLast(inputBuffer);
@@ -86,7 +88,7 @@ import java.util.LinkedList;
     }
   }
 
-  public void queueInputBuffer(InputBuffer inputBuffer) throws VpxDecoderException {
+  public void queueInputBuffer(VpxInputBuffer inputBuffer) throws VpxDecoderException {
     synchronized (lock) {
       maybeThrowDecoderError();
       dequeuedInputBuffers.remove(inputBuffer);
@@ -95,22 +97,20 @@ import java.util.LinkedList;
     }
   }
 
-  public OutputBuffer dequeueOutputBuffer() throws VpxDecoderException {
+  public VpxOutputBuffer dequeueOutputBuffer() throws VpxDecoderException {
     synchronized (lock) {
       maybeThrowDecoderError();
       if (queuedOutputBuffers.isEmpty()) {
         return null;
       }
-      OutputBuffer outputBuffer = queuedOutputBuffers.removeFirst();
+      VpxOutputBuffer outputBuffer = queuedOutputBuffers.removeFirst();
-      dequeuedOutputBuffers.add(outputBuffer);
       return outputBuffer;
     }
   }
 
-  public void releaseOutputBuffer(OutputBuffer outputBuffer) throws VpxDecoderException {
+  public void releaseOutputBuffer(VpxOutputBuffer outputBuffer) throws VpxDecoderException {
     synchronized (lock) {
       maybeThrowDecoderError();
-      dequeuedOutputBuffers.remove(outputBuffer);
       availableOutputBuffers[availableOutputBufferCount++] = outputBuffer;
       maybeNotifyDecodeLoop();
     }
@@ -128,9 +128,6 @@ import java.util.LinkedList;
       while (!queuedOutputBuffers.isEmpty()) {
         availableOutputBuffers[availableOutputBufferCount++] = queuedOutputBuffers.removeFirst();
       }
-      while (!dequeuedOutputBuffers.isEmpty()) {
-        availableOutputBuffers[availableOutputBufferCount++] = dequeuedOutputBuffers.removeFirst();
-      }
     }
   }
 
@@ -187,8 +184,8 @@ import java.util.LinkedList;
 
   private boolean decodeBuffer(VpxDecoder decoder) throws InterruptedException,
       VpxDecoderException {
-    InputBuffer inputBuffer;
+    VpxInputBuffer inputBuffer;
-    OutputBuffer outputBuffer;
+    VpxOutputBuffer outputBuffer;
 
     // Wait until we have an input buffer to decode, and an output buffer to decode into.
     synchronized (lock) {
@@ -238,7 +235,7 @@ import java.util.LinkedList;
     return true;
   }
 
-  /* package */ static final class InputBuffer {
+  /* package */ static final class VpxInputBuffer {
 
     public final SampleHolder sampleHolder;
 
@@ -246,75 +243,11 @@ import java.util.LinkedList;
     public int height;
     public int flags;
 
-    public InputBuffer() {
+    public VpxInputBuffer() {
       sampleHolder = new SampleHolder(SampleHolder.BUFFER_REPLACEMENT_MODE_DIRECT);
       sampleHolder.data = ByteBuffer.allocateDirect(INPUT_BUFFER_SIZE);
     }
 
   }
 
-  /* package */ static final class OutputBuffer {
-
-    public ByteBuffer data;
-    public long timestampUs;
-    public int width;
-    public int height;
-    public int flags;
-    public ByteBuffer[] yuvPlanes;
-    public int[] yuvStrides;
-    public int mode;
-
-    /**
-     * This method is called from C++ through JNI after decoding is done. It will resize the
-     * buffer based on the given dimensions.
-     */
-    public void initForRgbFrame(int width, int height) {
-      this.width = width;
-      this.height = height;
-      int minimumRgbSize = width * height * 2;
-      if (data == null || data.capacity() < minimumRgbSize) {
-        data = ByteBuffer.allocateDirect(minimumRgbSize);
-        yuvPlanes = null;
-      }
-      data.position(0);
-      data.limit(minimumRgbSize);
-    }
-
-    /**
-     * This method is called from C++ through JNI after decoding is done. It will resize the
-     * buffer based on the given stride.
-     */
-    public void initForYuvFrame(int width, int height, int yStride, int uvStride) {
-      this.width = width;
-      this.height = height;
-      int yLength = yStride * height;
-      int uvLength = uvStride * ((height + 1) / 2);
-      int minimumYuvSize = yLength + (uvLength * 2);
-      if (data == null || data.capacity() < minimumYuvSize) {
-        data = ByteBuffer.allocateDirect(minimumYuvSize);
-      }
-      data.limit(minimumYuvSize);
-      if (yuvPlanes == null) {
-        yuvPlanes = new ByteBuffer[3];
-      }
-      // Rewrapping has to be done on every frame since the stride might have changed.
-      data.position(0);
-      yuvPlanes[0] = data.slice();
-      yuvPlanes[0].limit(yLength);
-      data.position(yLength);
-      yuvPlanes[1] = data.slice();
-      yuvPlanes[1].limit(uvLength);
-      data.position(yLength + uvLength);
-      yuvPlanes[2] = data.slice();
-      yuvPlanes[2].limit(uvLength);
-      if (yuvStrides == null) {
-        yuvStrides = new int[3];
-      }
-      yuvStrides[0] = yStride;
-      yuvStrides[1] = uvStride;
-      yuvStrides[2] = uvStride;
-    }
-
-  }
-
 }

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/VpxOutputBuffer.java

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer.ext.vp9;
+
+import java.nio.ByteBuffer;
+
+/**
+ * OutputBuffer for storing the video frame.
+ */
+public final class VpxOutputBuffer {
+
+  public ByteBuffer data;
+  public long timestampUs;
+  public int width;
+  public int height;
+  public int flags;
+  public ByteBuffer[] yuvPlanes;
+  public int[] yuvStrides;
+  public int mode;
+
+  /**
+   * This method is called from C++ through JNI after decoding is done. It will resize the
+   * buffer based on the given dimensions.
+   */
+  public void initForRgbFrame(int width, int height) {
+    this.width = width;
+    this.height = height;
+    int minimumRgbSize = width * height * 2;
+    if (data == null || data.capacity() < minimumRgbSize) {
+      data = ByteBuffer.allocateDirect(minimumRgbSize);
+      yuvPlanes = null;
+    }
+    data.position(0);
+    data.limit(minimumRgbSize);
+  }
+
+  /**
+   * This method is called from C++ through JNI after decoding is done. It will resize the
+   * buffer based on the given stride.
+   */
+  public void initForYuvFrame(int width, int height, int yStride, int uvStride) {
+    this.width = width;
+    this.height = height;
+    int yLength = yStride * height;
+    int uvLength = uvStride * ((height + 1) / 2);
+    int minimumYuvSize = yLength + (uvLength * 2);
+    if (data == null || data.capacity() < minimumYuvSize) {
+      data = ByteBuffer.allocateDirect(minimumYuvSize);
+    }
+    data.limit(minimumYuvSize);
+    if (yuvPlanes == null) {
+      yuvPlanes = new ByteBuffer[3];
+    }
+    // Rewrapping has to be done on every frame since the stride might have changed.
+    data.position(0);
+    yuvPlanes[0] = data.slice();
+    yuvPlanes[0].limit(yLength);
+    data.position(yLength);
+    yuvPlanes[1] = data.slice();
+    yuvPlanes[1].limit(uvLength);
+    data.position(yLength + uvLength);
+    yuvPlanes[2] = data.slice();
+    yuvPlanes[2].limit(uvLength);
+    if (yuvStrides == null) {
+      yuvStrides = new int[3];
+    }
+    yuvStrides[0] = yStride;
+    yuvStrides[1] = uvStride;
+    yuvStrides[2] = uvStride;
+  }
+
+}

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/VpxOutputBufferRenderer.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.android.exoplayer.ext.vp9;
+
+/**
+ * Renders the {@link VpxOutputBuffer}.
+ */
+public interface VpxOutputBufferRenderer {
+
+  /**
+   * Sets the output buffer to be rendered.
+   */
+  void setOutputBuffer(VpxOutputBuffer outputBuffer);
+
+}

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/VpxRenderer.java

@@ -15,8 +15,6 @@
  */
 package com.google.android.exoplayer.ext.vp9;
 
-import com.google.android.exoplayer.ext.vp9.VpxDecoderWrapper.OutputBuffer;
-
 import android.opengl.GLES20;
 import android.opengl.GLSurfaceView;
 
@@ -67,7 +65,7 @@ import javax.microedition.khronos.opengles.GL10;
   private int program;
   private int texLocation;
   private FloatBuffer textureCoords;
-  private volatile OutputBuffer outputBuffer;
+  private VpxOutputBuffer outputBuffer;
   private int previousWidth;
   private int previousStride;
 
@@ -82,7 +80,7 @@ import javax.microedition.khronos.opengles.GL10;
    *
    * @param outputBuffer OutputBuffer containing the YUV Frame to be rendered
    */
-  public void setFrame(OutputBuffer outputBuffer) {
+  public synchronized void setFrame(VpxOutputBuffer outputBuffer) {
     this.outputBuffer = outputBuffer;
   }
 
@@ -121,8 +119,8 @@ import javax.microedition.khronos.opengles.GL10;
 
   @Override
   public void onDrawFrame(GL10 unused) {
-    OutputBuffer outputBuffer = this.outputBuffer;
+    synchronized (this) {
-    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
+      VpxOutputBuffer outputBuffer = this.outputBuffer;
       if (outputBuffer == null) {
         // Nothing to render yet.
         return;
@@ -132,8 +130,9 @@ import javax.microedition.khronos.opengles.GL10;
         GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + i);
         GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, yuvTextures[i]);
         GLES20.glPixelStorei(GLES20.GL_UNPACK_ALIGNMENT, 1);
-      GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, outputBuffer.yuvStrides[i],
+        GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE,
-          h, 0, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, outputBuffer.yuvPlanes[i]);
+            outputBuffer.yuvStrides[i], h, 0, GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE,
+            outputBuffer.yuvPlanes[i]);
       }
       // Set cropping of stride if either width or stride has changed.
       if (previousWidth != outputBuffer.width || previousStride != outputBuffer.yuvStrides[0]) {
@@ -148,6 +147,8 @@ import javax.microedition.khronos.opengles.GL10;
         previousWidth = outputBuffer.width;
         previousStride = outputBuffer.yuvStrides[0];
       }
+    }
+    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
     GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
     checkNoGLES2Error();
   }

extensions/vp9/src/main/java/com/google/android/exoplayer/ext/vp9/VpxVideoSurfaceView.java

@@ -15,8 +15,6 @@
  */
 package com.google.android.exoplayer.ext.vp9;
 
-import com.google.android.exoplayer.ext.vp9.VpxDecoderWrapper.OutputBuffer;
-
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.opengl.GLSurfaceView;
@@ -26,7 +24,7 @@ import android.util.AttributeSet;
  * A GLSurfaceView extension that scales itself to the given aspect ratio.
  */
 @TargetApi(11)
-public class VpxVideoSurfaceView extends GLSurfaceView {
+public class VpxVideoSurfaceView extends GLSurfaceView implements VpxOutputBufferRenderer {
 
   private final VpxRenderer renderer;
 
@@ -43,7 +41,8 @@ public class VpxVideoSurfaceView extends GLSurfaceView {
     setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
   }
 
-  public void renderFrame(OutputBuffer outputBuffer) {
+  @Override
+  public void setOutputBuffer(VpxOutputBuffer outputBuffer) {
     renderer.setFrame(outputBuffer);
     requestRender();
   }

extensions/vp9/src/main/jni/vpx_jni.cc

@@ -44,7 +44,7 @@
     Java_com_google_android_exoplayer_ext_vp9_VpxDecoder_ ## NAME \
       (JNIEnv* env, jobject thiz, ##__VA_ARGS__)\
 
-// JNI references for OutputBuffer class.
+// JNI references for VpxOutputBuffer class.
 static jmethodID initForRgbFrame;
 static jmethodID initForYuvFrame;
 static jfieldID dataField;
@@ -69,7 +69,7 @@ FUNC(jlong, vpxInit) {
 
   // Populate JNI References.
   const jclass outputBufferClass = env->FindClass(
-      "com/google/android/exoplayer/ext/vp9/VpxDecoderWrapper$OutputBuffer");
+      "com/google/android/exoplayer/ext/vp9/VpxOutputBuffer");
   initForYuvFrame = env->GetMethodID(outputBufferClass, "initForYuvFrame",
                                      "(IIII)V");
   initForRgbFrame = env->GetMethodID(outputBufferClass, "initForRgbFrame",