diff --git a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/LibvpxVideoRenderer.java b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/LibvpxVideoRenderer.java
index 5a2093b2b7..101f05cd82 100644
--- a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/LibvpxVideoRenderer.java
+++ b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/LibvpxVideoRenderer.java
@@ -30,6 +30,7 @@ import com.google.android.exoplayer2.ExoPlaybackException;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.FormatHolder;
+import com.google.android.exoplayer2.PlayerMessage.Target;
 import com.google.android.exoplayer2.decoder.DecoderCounters;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.drm.DrmSession;
@@ -45,7 +46,20 @@ import com.google.android.exoplayer2.video.VideoRendererEventListener.EventDispa
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 
-/** Decodes and renders video using the native VP9 decoder. */
+/**
+ * Decodes and renders video using the native VP9 decoder.
+ *
+ * <p>This renderer accepts the following messages sent via {@link ExoPlayer#createMessage(Target)}
+ * on the playback thread:
+ *
+ * <ul>
+ *   <li>Message with type {@link C#MSG_SET_SURFACE} to set the output surface. The message payload
+ *       should be the target {@link Surface}, or null.
+ *   <li>Message with type {@link #MSG_SET_OUTPUT_BUFFER_RENDERER} to set the output buffer
+ *       renderer. The message payload should be the target {@link VpxOutputBufferRenderer}, or
+ *       null.
+ * </ul>
+ */
 public class LibvpxVideoRenderer extends BaseRenderer {
 
   @Retention(RetentionPolicy.SOURCE)
@@ -70,9 +84,9 @@ public class LibvpxVideoRenderer extends BaseRenderer {
   private static final int REINITIALIZATION_STATE_WAIT_END_OF_STREAM = 2;
 
   /**
-   * The type of a message that can be passed to an instance of this class via
-   * {@link ExoPlayer#sendMessages} or {@link ExoPlayer#blockingSendMessages}. The message object
-   * should be the target {@link VpxOutputBufferRenderer}, or null.
+   * The type of a message that can be passed to an instance of this class via {@link
+   * ExoPlayer#createMessage(Target)}. The message payload should be the target {@link
+   * VpxOutputBufferRenderer}, or null.
    */
   public static final int MSG_SET_OUTPUT_BUFFER_RENDERER = C.MSG_CUSTOM_BASE;
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/C.java b/library/core/src/main/java/com/google/android/exoplayer2/C.java
index d6e61c12b1..045f3bfc6e 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/C.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/C.java
@@ -23,6 +23,7 @@ import android.media.MediaCodec;
 import android.media.MediaFormat;
 import android.support.annotation.IntDef;
 import android.view.Surface;
+import com.google.android.exoplayer2.PlayerMessage.Target;
 import com.google.android.exoplayer2.util.Util;
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
@@ -642,37 +643,37 @@ public final class C {
   public static final UUID PLAYREADY_UUID = new UUID(0x9A04F07998404286L, 0xAB92E65BE0885F95L);
 
   /**
-   * The type of a message that can be passed to a video {@link Renderer} via
-   * {@link ExoPlayer#sendMessages} or {@link ExoPlayer#blockingSendMessages}. The message object
-   * should be the target {@link Surface}, or null.
+   * The type of a message that can be passed to a video {@link Renderer} via {@link
+   * ExoPlayer#createMessage(Target)}. The message payload should be the target {@link Surface}, or
+   * null.
    */
   public static final int MSG_SET_SURFACE = 1;
 
   /**
-   * A type of a message that can be passed to an audio {@link Renderer} via
-   * {@link ExoPlayer#sendMessages} or {@link ExoPlayer#blockingSendMessages}. The message object
-   * should be a {@link Float} with 0 being silence and 1 being unity gain.
+   * A type of a message that can be passed to an audio {@link Renderer} via {@link
+   * ExoPlayer#createMessage(Target)}. The message payload should be a {@link Float} with 0 being
+   * silence and 1 being unity gain.
    */
   public static final int MSG_SET_VOLUME = 2;
 
   /**
-   * A type of a message that can be passed to an audio {@link Renderer} via
-   * {@link ExoPlayer#sendMessages} or {@link ExoPlayer#blockingSendMessages}. The message object
-   * should be an {@link com.google.android.exoplayer2.audio.AudioAttributes} instance that will
-   * configure the underlying audio track. If not set, the default audio attributes will be used.
-   * They are suitable for general media playback.
-   * <p>
-   * Setting the audio attributes during playback may introduce a short gap in audio output as the
-   * audio track is recreated. A new audio session id will also be generated.
-   * <p>
-   * If tunneling is enabled by the track selector, the specified audio attributes will be ignored,
-   * but they will take effect if audio is later played without tunneling.
-   * <p>
-   * If the device is running a build before platform API version 21, audio attributes cannot be set
-   * directly on the underlying audio track. In this case, the usage will be mapped onto an
+   * A type of a message that can be passed to an audio {@link Renderer} via {@link
+   * ExoPlayer#createMessage(Target)}. The message payload should be an {@link
+   * com.google.android.exoplayer2.audio.AudioAttributes} instance that will configure the
+   * underlying audio track. If not set, the default audio attributes will be used. They are
+   * suitable for general media playback.
+   *
+   * <p>Setting the audio attributes during playback may introduce a short gap in audio output as
+   * the audio track is recreated. A new audio session id will also be generated.
+   *
+   * <p>If tunneling is enabled by the track selector, the specified audio attributes will be
+   * ignored, but they will take effect if audio is later played without tunneling.
+   *
+   * <p>If the device is running a build before platform API version 21, audio attributes cannot be
+   * set directly on the underlying audio track. In this case, the usage will be mapped onto an
    * equivalent stream type using {@link Util#getStreamTypeForAudioUsage(int)}.
-   * <p>
-   * To get audio attributes that are equivalent to a legacy stream type, pass the stream type to
+   *
+   * <p>To get audio attributes that are equivalent to a legacy stream type, pass the stream type to
    * {@link Util#getAudioUsageForStreamType(int)} and use the returned {@link C.AudioUsage} to build
    * an audio attributes instance.
    */
@@ -680,17 +681,17 @@ public final class C {
 
   /**
    * The type of a message that can be passed to a {@link MediaCodec}-based video {@link Renderer}
-   * via {@link ExoPlayer#sendMessages} or {@link ExoPlayer#blockingSendMessages}. The message
-   * object should be one of the integer scaling modes in {@link C.VideoScalingMode}.
-   * <p>
-   * Note that the scaling mode only applies if the {@link Surface} targeted by the renderer is
+   * via {@link ExoPlayer#createMessage(Target)}. The message payload should be one of the integer
+   * scaling modes in {@link C.VideoScalingMode}.
+   *
+   * <p>Note that the scaling mode only applies if the {@link Surface} targeted by the renderer is
    * owned by a {@link android.view.SurfaceView}.
    */
   public static final int MSG_SET_SCALING_MODE = 4;
 
   /**
-   * Applications or extensions may define custom {@code MSG_*} constants greater than or equal to
-   * this value.
+   * Applications or extensions may define custom {@code MSG_*} constants that can be passed to
+   * {@link Renderer}s. These custom constants must be greater than or equal to this value.
    */
   public static final int MSG_CUSTOM_BASE = 10000;
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/audio/MediaCodecAudioRenderer.java b/library/core/src/main/java/com/google/android/exoplayer2/audio/MediaCodecAudioRenderer.java
index f73d63616b..a7063e5a7f 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/audio/MediaCodecAudioRenderer.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/audio/MediaCodecAudioRenderer.java
@@ -24,8 +24,10 @@ import android.os.Handler;
 import android.support.annotation.Nullable;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlaybackException;
+import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.PlaybackParameters;
+import com.google.android.exoplayer2.PlayerMessage.Target;
 import com.google.android.exoplayer2.audio.AudioRendererEventListener.EventDispatcher;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
@@ -41,6 +43,17 @@ import java.nio.ByteBuffer;
 
 /**
  * Decodes and renders audio using {@link MediaCodec} and an {@link AudioSink}.
+ *
+ * <p>This renderer accepts the following messages sent via {@link ExoPlayer#createMessage(Target)}
+ * on the playback thread:
+ *
+ * <ul>
+ *   <li>Message with type {@link C#MSG_SET_VOLUME} to set the volume. The message payload should be
+ *       a {@link Float} with 0 being silence and 1 being unity gain.
+ *   <li>Message with type {@link C#MSG_SET_AUDIO_ATTRIBUTES} to set the audio attributes. The
+ *       message payload should be an {@link com.google.android.exoplayer2.audio.AudioAttributes}
+ *       instance that will configure the underlying audio track.
+ * </ul>
  */
 @TargetApi(16)
 public class MediaCodecAudioRenderer extends MediaCodecRenderer implements MediaClock {
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/audio/SimpleDecoderAudioRenderer.java b/library/core/src/main/java/com/google/android/exoplayer2/audio/SimpleDecoderAudioRenderer.java
index eda8cfb15d..2f5e7bcf97 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/audio/SimpleDecoderAudioRenderer.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/audio/SimpleDecoderAudioRenderer.java
@@ -23,9 +23,11 @@ import android.support.annotation.IntDef;
 import com.google.android.exoplayer2.BaseRenderer;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlaybackException;
+import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Format;
 import com.google.android.exoplayer2.FormatHolder;
 import com.google.android.exoplayer2.PlaybackParameters;
+import com.google.android.exoplayer2.PlayerMessage.Target;
 import com.google.android.exoplayer2.audio.AudioRendererEventListener.EventDispatcher;
 import com.google.android.exoplayer2.decoder.DecoderCounters;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
@@ -45,6 +47,17 @@ import java.lang.annotation.RetentionPolicy;
 
 /**
  * Decodes and renders audio using a {@link SimpleDecoder}.
+ *
+ * <p>This renderer accepts the following messages sent via {@link ExoPlayer#createMessage(Target)}
+ * on the playback thread:
+ *
+ * <ul>
+ *   <li>Message with type {@link C#MSG_SET_VOLUME} to set the volume. The message payload should be
+ *       a {@link Float} with 0 being silence and 1 being unity gain.
+ *   <li>Message with type {@link C#MSG_SET_AUDIO_ATTRIBUTES} to set the audio attributes. The
+ *       message payload should be an {@link com.google.android.exoplayer2.audio.AudioAttributes}
+ *       instance that will configure the underlying audio track.
+ * </ul>
  */
 public abstract class SimpleDecoderAudioRenderer extends BaseRenderer implements MediaClock {
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java b/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java
index 895e290a75..f26db1054f 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java
@@ -32,7 +32,9 @@ import android.util.Log;
 import android.view.Surface;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlaybackException;
+import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Format;
+import com.google.android.exoplayer2.PlayerMessage.Target;
 import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
 import com.google.android.exoplayer2.drm.DrmInitData;
 import com.google.android.exoplayer2.drm.DrmSessionManager;
@@ -51,6 +53,18 @@ import java.nio.ByteBuffer;
 
 /**
  * Decodes and renders video using {@link MediaCodec}.
+ *
+ * <p>This renderer accepts the following messages sent via {@link ExoPlayer#createMessage(Target)}
+ * on the playback thread:
+ *
+ * <ul>
+ *   <li>Message with type {@link C#MSG_SET_SURFACE} to set the output surface. The message payload
+ *       should be the target {@link Surface}, or null.
+ *   <li>Message with type {@link C#MSG_SET_SCALING_MODE} to set the video scaling mode. The message
+ *       payload should be one of the integer scaling modes in {@link C.VideoScalingMode}. Note that
+ *       the scaling mode only applies if the {@link Surface} targeted by this renderer is owned by
+ *       a {@link android.view.SurfaceView}.
+ * </ul>
  */
 @TargetApi(16)
 public class MediaCodecVideoRenderer extends MediaCodecRenderer {