Fix audio slow motion flattening

PiperOrigin-RevId: 488981968

library/common/src/main/java/com/google/android/exoplayer2/audio/AudioProcessingPipeline.java

@@ -15,7 +15,6 @@
  */
  */
 package com.google.android.exoplayer2.audio;
 package com.google.android.exoplayer2.audio;
 
 
-import static com.google.android.exoplayer2.audio.AudioProcessor.EMPTY_BUFFER;
 import static com.google.android.exoplayer2.util.Assertions.checkState;
 import static com.google.android.exoplayer2.util.Assertions.checkState;
 
 
 import androidx.annotation.Nullable;
 import androidx.annotation.Nullable;
@@ -23,6 +22,7 @@ import com.google.android.exoplayer2.audio.AudioProcessor.AudioFormat;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import java.nio.ByteBuffer;
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 import java.util.ArrayList;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.List;
 
 
@@ -66,6 +66,11 @@ import java.util.List;
  * </ul>
  * </ul>
  */
  */
 public final class AudioProcessingPipeline {
 public final class AudioProcessingPipeline {
+
+  /** An empty, direct {@link ByteBuffer}. */
+  private static final ByteBuffer EMPTY_BUFFER =
+      ByteBuffer.allocateDirect(0).order(ByteOrder.nativeOrder());
+
   /** The {@link AudioProcessor} instances passed to {@link AudioProcessingPipeline}. */
   /** The {@link AudioProcessor} instances passed to {@link AudioProcessingPipeline}. */
   private final ImmutableList<AudioProcessor> audioProcessors;
   private final ImmutableList<AudioProcessor> audioProcessors;
   /**
   /**