Don't hold a lock while rendering in VpxRenderer.

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

@@ -106,7 +106,6 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
   private VpxDecoderWrapper decoder;
   private VpxInputBuffer inputBuffer;
   private VpxOutputBuffer outputBuffer;
-  private VpxOutputBuffer renderedOutputBuffer;
 
   private Bitmap bitmap;
   private boolean drawnToSurface;
@@ -181,13 +180,7 @@ 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)) {
@@ -226,7 +219,7 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
 
     if (outputBuffer.flags == VpxDecoderWrapper.FLAG_END_OF_STREAM) {
       outputStreamEnded = true;
-      releaseOutputBuffer(outputBuffer);
+      decoder.releaseOutputBuffer(outputBuffer);
       outputBuffer = null;
       return;
     }
@@ -241,7 +234,7 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
       if (droppedFrameCount == maxDroppedFrameCountToNotify) {
         notifyAndResetDroppedFrameCount();
       }
-      releaseOutputBuffer(outputBuffer);
+      decoder.releaseOutputBuffer(outputBuffer);
       outputBuffer = null;
       return;
     }
@@ -270,7 +263,7 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
     renderBuffer();
   }
 
-  private void renderBuffer() throws VpxDecoderException {
+  private void renderBuffer() {
     codecCounters.renderedOutputBufferCount++;
     notifyIfVideoSizeChanged(outputBuffer);
     if (outputBuffer.mode == VpxDecoder.OUTPUT_MODE_RGB && surface != null) {
@@ -279,22 +272,16 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
         drawnToSurface = true;
         notifyDrawnToSurface(surface);
       }
+      outputBuffer.release();
     } else if (outputBuffer.mode == VpxDecoder.OUTPUT_MODE_YUV && outputBufferRenderer != null) {
+      // The renderer will release the buffer.
       outputBufferRenderer.setOutputBuffer(outputBuffer);
+    } else {
+      outputBuffer.release();
     }
-    // Release the output buffer we rendered during the previous cycle, now that we delivered a new
-    // buffer.
-    releaseOutputBuffer(renderedOutputBuffer);
-    renderedOutputBuffer = outputBuffer;
     outputBuffer = null;
   }
 
-  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) {
@@ -350,7 +337,7 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
     return true;
   }
 
-  private void checkForDiscontinuity(long positionUs) throws VpxDecoderException {
+  private void checkForDiscontinuity(long positionUs) {
     if (decoder == null) {
       return;
     }
@@ -360,12 +347,12 @@ public final class LibvpxVideoTrackRenderer extends SampleSourceTrackRenderer {
     }
   }
 
-  private void flushDecoder() throws VpxDecoderException {
+  private void flushDecoder() {
     inputBuffer = null;
-    VpxOutputBuffer bufferToRelease = outputBuffer;
-    // Set this to null now because releaseOutputBuffer could throw an exception.
+    if (outputBuffer != null) {
+      decoder.releaseOutputBuffer(outputBuffer);
       outputBuffer = null;
-    releaseOutputBuffer(bufferToRelease);
+    }
     decoder.flush();
   }
 

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

@@ -24,14 +24,15 @@ import java.util.LinkedList;
 /**
  * Wraps {@link VpxDecoder}, exposing a higher level decoder interface.
  */
-/* package */ class VpxDecoderWrapper extends Thread {
+/* package */ final class VpxDecoderWrapper extends Thread {
 
   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.
+   * The number of input buffers and the number of output buffers. The track renderer may limit the
+   * minimum possible value due to requiring multiple output buffers to be dequeued at a time for it
+   * to make progress.
    */
   private static final int NUM_BUFFERS = 16;
 
@@ -66,7 +67,7 @@ import java.util.LinkedList;
     availableOutputBufferCount = NUM_BUFFERS;
     for (int i = 0; i < NUM_BUFFERS; i++) {
       availableInputBuffers[i] = new VpxInputBuffer();
-      availableOutputBuffers[i] = new VpxOutputBuffer();
+      availableOutputBuffers[i] = new VpxOutputBuffer(this);
     }
   }
 
@@ -105,19 +106,22 @@ import java.util.LinkedList;
       if (queuedOutputBuffers.isEmpty()) {
         return null;
       }
-      VpxOutputBuffer outputBuffer = queuedOutputBuffers.removeFirst();
-      return outputBuffer;
+      return queuedOutputBuffers.removeFirst();
     }
   }
 
-  public void releaseOutputBuffer(VpxOutputBuffer outputBuffer) throws VpxDecoderException {
+  public void releaseOutputBuffer(VpxOutputBuffer outputBuffer) {
     synchronized (lock) {
-      maybeThrowDecoderError();
       availableOutputBuffers[availableOutputBufferCount++] = outputBuffer;
       maybeNotifyDecodeLoop();
     }
   }
 
+  /**
+   * Flushes input/output buffers that have not been dequeued yet and returns ownership of any
+   * dequeued input buffer to the decoder. Flushes any pending output currently in the decoder. The
+   * caller is still responsible for releasing any dequeued output buffers.
+   */
   public void flush() {
     synchronized (lock) {
       flushDecodedOutputBuffer = true;
@@ -159,7 +163,7 @@ import java.util.LinkedList;
    * Should only be called whilst synchronized on the lock object.
    */
   private void maybeNotifyDecodeLoop() {
-    if (!queuedInputBuffers.isEmpty() && availableOutputBufferCount > 0) {
+    if (canDecodeBuffer()) {
       lock.notify();
     }
   }
@@ -192,7 +196,7 @@ import java.util.LinkedList;
 
     // Wait until we have an input buffer to decode, and an output buffer to decode into.
     synchronized (lock) {
-      while (!released && (queuedInputBuffers.isEmpty() || availableOutputBufferCount == 0)) {
+      while (!released && !canDecodeBuffer()) {
         lock.wait();
       }
       if (released) {
@@ -238,6 +242,10 @@ import java.util.LinkedList;
     return true;
   }
 
+  private boolean canDecodeBuffer() {
+    return !queuedInputBuffers.isEmpty() && availableOutputBufferCount > 0;
+  }
+
   /* package */ static final class VpxInputBuffer {
 
     public final SampleHolder sampleHolder;

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

@@ -26,6 +26,12 @@ public final class VpxOutputBuffer {
   public static final int COLORSPACE_BT601 = 1;
   public static final int COLORSPACE_BT709 = 2;
 
+  private final VpxDecoderWrapper decoder;
+
+  /* package */ VpxOutputBuffer(VpxDecoderWrapper decoder) {
+    this.decoder = decoder;
+  }
+
   /**
    * RGB buffer for RGB mode.
    */
@@ -43,10 +49,16 @@ public final class VpxOutputBuffer {
   public int colorspace;
 
   /**
-   * This method is called from C++ through JNI after decoding is done. It will resize the
-   * buffer based on the given dimensions.
+   * Releases the buffer back to the decoder, allowing it to be reused.
+   */
+  public void release() {
+    decoder.releaseOutputBuffer(this);
+  }
+
+  /**
+   * Resizes the buffer based on the given dimensions. Called via JNI after decoding completes.
    */
-  public void initForRgbFrame(int width, int height) {
+  /* package */ void initForRgbFrame(int width, int height) {
     this.width = width;
     this.height = height;
     int minimumRgbSize = width * height * 2;
@@ -59,10 +71,10 @@ public final class VpxOutputBuffer {
   }
 
   /**
-   * This method is called from C++ through JNI after decoding is done. It will resize the
-   * buffer based on the given stride.
+   * Resizes the buffer based on the given stride. Called via JNI after decoding completes.
    */
-  public void initForYuvFrame(int width, int height, int yStride, int uvStride, int colorspace) {
+  /* package */ void initForYuvFrame(int width, int height, int yStride, int uvStride,
+      int colorspace) {
     this.width = width;
     this.height = height;
     this.colorspace = colorspace;

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

@@ -21,7 +21,7 @@ package com.google.android.exoplayer.ext.vp9;
 public interface VpxOutputBufferRenderer {
 
   /**
-   * Sets the output buffer to be rendered.
+   * Sets the output buffer to be rendered. The renderer is responsible for releasing the buffer.
    */
   void setOutputBuffer(VpxOutputBuffer outputBuffer);
 

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

@@ -21,6 +21,7 @@ import android.opengl.GLSurfaceView;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.FloatBuffer;
+import java.util.concurrent.atomic.AtomicReference;
 
 import javax.microedition.khronos.egl.EGLConfig;
 import javax.microedition.khronos.opengles.GL10;
@@ -72,18 +73,21 @@ import javax.microedition.khronos.opengles.GL10;
       1.0f, 1.0f,
       1.0f, -1.0f);
   private final int[] yuvTextures = new int[3];
+  private final AtomicReference<VpxOutputBuffer> pendingOutputBufferReference;
 
   private int program;
   private int texLocation;
   private int colorMatrixLocation;
   private FloatBuffer textureCoords;
-  private VpxOutputBuffer outputBuffer;
   private int previousWidth;
   private int previousStride;
 
+  private VpxOutputBuffer renderedOutputBuffer; // Accessed only from the GL thread.
+
   public VpxRenderer() {
     previousWidth = -1;
     previousStride = -1;
+    pendingOutputBufferReference = new AtomicReference<>();
   }
 
   /**
@@ -92,8 +96,12 @@ import javax.microedition.khronos.opengles.GL10;
    *
    * @param outputBuffer OutputBuffer containing the YUV Frame to be rendered
    */
-  public synchronized void setFrame(VpxOutputBuffer outputBuffer) {
-    this.outputBuffer = outputBuffer;
+  public void setFrame(VpxOutputBuffer outputBuffer) {
+    VpxOutputBuffer oldPendingOutputBuffer = pendingOutputBufferReference.getAndSet(outputBuffer);
+    if (oldPendingOutputBuffer != null) {
+      // The old pending output buffer will never be used for rendering, so release it now.
+      oldPendingOutputBuffer.release();
+    }
   }
 
   @Override
@@ -134,13 +142,18 @@ import javax.microedition.khronos.opengles.GL10;
 
   @Override
   public void onDrawFrame(GL10 unused) {
-    synchronized (this) {
-      VpxOutputBuffer outputBuffer = this.outputBuffer;
-      if (outputBuffer == null) {
-        // Nothing to render yet.
+    VpxOutputBuffer pendingOutputBuffer = pendingOutputBufferReference.getAndSet(null);
+    if (pendingOutputBuffer == null && renderedOutputBuffer == null) {
+      // There is no output buffer to render at the moment.
       return;
     }
-
+    if (pendingOutputBuffer != null) {
+      if (renderedOutputBuffer != null) {
+        renderedOutputBuffer.release();
+      }
+      renderedOutputBuffer = pendingOutputBuffer;
+    }
+    VpxOutputBuffer outputBuffer = renderedOutputBuffer;
     // Set color matrix. Assume BT709 if the color space is unknown.
     float[] colorConversion = outputBuffer.colorspace == VpxOutputBuffer.COLORSPACE_BT601
         ? kColorConversion601 : kColorConversion709;
@@ -168,7 +181,6 @@ 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();