Fix bypass mode when the stream is empty

#minor-release
Issue: #8374
PiperOrigin-RevId: 348792965

RELEASENOTES.md

@@ -26,6 +26,8 @@
         ([#5887](https://github.com/google/ExoPlayer/issues/5887)).
     *   Fix bug where `AnalyticsListener` callbacks can arrive in the wrong
         order ([#8048](https://github.com/google/ExoPlayer/issues/8048)).
+    *   Fix `MediaCodecRenderer` issue where empty streams would fail to play in
+        bypass mode ([#8374](https://github.com/google/ExoPlayer/issues/8374)).
     *   Add `onEvents` callback to `Player.EventListener` and
         `AnalyticsListener` to notify when all simultaneous state changes have
         been handled and the values reported through callbacks are again

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/BatchBuffer.java

@@ -153,26 +153,26 @@ private boolean canBatch(DecoderInputBuffer accessUnit) {
   }
 
   private void putAccessUnit(DecoderInputBuffer accessUnit) {
-    @Nullable ByteBuffer accessUnitData = accessUnit.data;
-    if (accessUnitData != null) {
-      accessUnit.flip();
-      ensureSpaceForWrite(accessUnitData.remaining());
-      this.data.put(accessUnitData);
-    }
-
     if (accessUnit.isEndOfStream()) {
       setFlags(C.BUFFER_FLAG_END_OF_STREAM);
-    }
-    if (accessUnit.isDecodeOnly()) {
-      setFlags(C.BUFFER_FLAG_DECODE_ONLY);
-    }
-    if (accessUnit.isKeyFrame()) {
-      setFlags(C.BUFFER_FLAG_KEY_FRAME);
-    }
-    accessUnitCount++;
-    timeUs = accessUnit.timeUs;
-    if (accessUnitCount == 1) { // First read of the buffer
-      firstAccessUnitTimeUs = timeUs;
+    } else {
+      timeUs = accessUnit.timeUs;
+      if (accessUnit.isDecodeOnly()) {
+        setFlags(C.BUFFER_FLAG_DECODE_ONLY);
+      }
+      if (accessUnit.isKeyFrame()) {
+        setFlags(C.BUFFER_FLAG_KEY_FRAME);
+      }
+      @Nullable ByteBuffer accessUnitData = accessUnit.data;
+      if (accessUnitData != null) {
+        accessUnit.flip();
+        ensureSpaceForWrite(accessUnitData.remaining());
+        this.data.put(accessUnitData);
+      }
+      accessUnitCount++;
+      if (accessUnitCount == 1) {
+        firstAccessUnitTimeUs = timeUs;
+      }
     }
     accessUnit.clear();
   }

library/core/src/main/java/com/google/android/exoplayer2/mediacodec/MediaCodecRenderer.java

@@ -397,6 +397,11 @@ public MediaCodecRenderer(
     outputStreamStartPositionUs = C.TIME_UNSET;
     outputStreamOffsetUs = C.TIME_UNSET;
     bypassBatchBuffer = new BatchBuffer();
+    bypassBatchBuffer.ensureSpaceForWrite(/* length= */ 0);
+    // MediaCodec outputs audio buffers in native endian:
+    // https://developer.android.com/reference/android/media/MediaCodec#raw-audio-buffers
+    // and code called from MediaCodecAudioRenderer.processOutputBuffer expects this endianness.
+    bypassBatchBuffer.data.order(ByteOrder.nativeOrder());
     resetCodecStateForRelease();
   }
 
@@ -2122,15 +2127,15 @@ private FrameworkMediaCrypto getFrameworkMediaCrypto(DrmSession drmSession)
    *     iteration of the rendering loop.
    * @param elapsedRealtimeUs {@link SystemClock#elapsedRealtime()} in microseconds, measured at the
    *     start of the current iteration of the rendering loop.
-   * @return If more buffers are ready to be rendered.
+   * @return Whether immediately calling this method again will make more progress.
    * @throws ExoPlaybackException If an error occurred while processing a buffer or handling a
    *     format change.
    */
   private boolean bypassRender(long positionUs, long elapsedRealtimeUs)
       throws ExoPlaybackException {
     BatchBuffer batchBuffer = bypassBatchBuffer;
 
-    // Let's process the pending buffer if any.
+    // Process any data in the batch buffer.
     checkState(!outputStreamEnded);
     if (!batchBuffer.isEmpty()) { // Optimisation: Do not process buffer if empty.
       if (processOutputBuffer(
@@ -2145,12 +2150,13 @@ private boolean bypassRender(long positionUs, long elapsedRealtimeUs)
           batchBuffer.isDecodeOnly(),
           batchBuffer.isEndOfStream(),
           outputFormat)) {
-        // Buffer completely processed
         onProcessedOutputBuffer(batchBuffer.getLastAccessUnitTimeUs());
       } else {
-        return false; // Could not process buffer, let's try later.
+        // Could not process the whole buffer. Try again later.
+        return false;
       }
     }
+    // Process the end of stream, if it has been reached.
     if (batchBuffer.isEndOfStream()) {
       outputStreamEnded = true;
       return false;
@@ -2185,19 +2191,17 @@ private boolean bypassRender(long positionUs, long elapsedRealtimeUs)
       onInputFormatChanged(formatHolder);
     }
 
+    boolean haveDataToProcess = false;
     if (batchBuffer.isEndOfStream()) {
       inputStreamEnded = true;
+      haveDataToProcess = true;
     }
-
-    if (batchBuffer.isEmpty()) {
-      return false; // The buffer could not be filled, there is nothing more to do.
+    if (!batchBuffer.isEmpty()) {
+      batchBuffer.flip();
+      haveDataToProcess = true;
     }
-    batchBuffer.flip(); // Buffer at least partially full, it can now be processed.
-    // MediaCodec outputs buffers in native endian:
-    // https://developer.android.com/reference/android/media/MediaCodec#raw-audio-buffers
-    // and code called from processOutputBuffer expects this endianness.
-    batchBuffer.data.order(ByteOrder.nativeOrder());
-    return true;
+
+    return haveDataToProcess;
   }
 
   /**

library/core/src/test/java/com/google/android/exoplayer2/e2etest/SilencePlaybackTest.java

@@ -56,4 +56,25 @@ public void test_500ms() throws Exception {
     DumpFileAsserts.assertOutput(
         applicationContext, playbackOutput, "playbackdumps/silence/500ms.dump");
   }
+
+  @Test
+  public void test_0ms() throws Exception {
+    Context applicationContext = ApplicationProvider.getApplicationContext();
+    CapturingRenderersFactory capturingRenderersFactory =
+        new CapturingRenderersFactory(applicationContext);
+    SimpleExoPlayer player =
+        new SimpleExoPlayer.Builder(applicationContext, capturingRenderersFactory)
+            .setClock(new AutoAdvancingFakeClock())
+            .build();
+    PlaybackOutput playbackOutput = PlaybackOutput.register(player, capturingRenderersFactory);
+
+    player.setMediaSource(new SilenceMediaSource(/* durationUs= */ 0));
+    player.prepare();
+    player.play();
+    TestPlayerRunHelper.runUntilPlaybackState(player, Player.STATE_ENDED);
+    player.release();
+
+    DumpFileAsserts.assertOutput(
+        applicationContext, playbackOutput, "playbackdumps/silence/0ms.dump");
+  }
 }