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 b6663ac3d7..5e9d8d0897 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
@@ -174,8 +174,8 @@ public class LibvpxVideoRenderer extends BaseRenderer {
    */
   public LibvpxVideoRenderer(
       long allowedJoiningTimeMs,
-      Handler eventHandler,
-      VideoRendererEventListener eventListener,
+      @Nullable Handler eventHandler,
+      @Nullable VideoRendererEventListener eventListener,
       int maxDroppedFramesToNotify) {
     this(
         allowedJoiningTimeMs,
@@ -206,10 +206,10 @@ public class LibvpxVideoRenderer extends BaseRenderer {
    */
   public LibvpxVideoRenderer(
       long allowedJoiningTimeMs,
-      Handler eventHandler,
-      VideoRendererEventListener eventListener,
+      @Nullable Handler eventHandler,
+      @Nullable VideoRendererEventListener eventListener,
       int maxDroppedFramesToNotify,
-      DrmSessionManager<ExoMediaCrypto> drmSessionManager,
+      @Nullable DrmSessionManager<ExoMediaCrypto> drmSessionManager,
       boolean playClearSamplesWithoutKeys,
       boolean disableLoopFilter) {
     this(
@@ -249,10 +249,10 @@ public class LibvpxVideoRenderer extends BaseRenderer {
    */
   public LibvpxVideoRenderer(
       long allowedJoiningTimeMs,
-      Handler eventHandler,
-      VideoRendererEventListener eventListener,
+      @Nullable Handler eventHandler,
+      @Nullable VideoRendererEventListener eventListener,
       int maxDroppedFramesToNotify,
-      DrmSessionManager<ExoMediaCrypto> drmSessionManager,
+      @Nullable DrmSessionManager<ExoMediaCrypto> drmSessionManager,
       boolean playClearSamplesWithoutKeys,
       boolean disableLoopFilter,
       boolean enableRowMultiThreadMode,
diff --git a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxDecoder.java b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxDecoder.java
index 93a4a2fc1f..0efd4bd0ea 100644
--- a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxDecoder.java
+++ b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxDecoder.java
@@ -33,7 +33,7 @@ import java.nio.ByteBuffer;
   private static final int DECODE_ERROR = 1;
   private static final int DRM_ERROR = 2;
 
-  private final ExoMediaCrypto exoMediaCrypto;
+  @Nullable private final ExoMediaCrypto exoMediaCrypto;
   private final long vpxDecContext;
 
   @C.VideoOutputMode private volatile int outputMode;
@@ -55,7 +55,7 @@ import java.nio.ByteBuffer;
       int numInputBuffers,
       int numOutputBuffers,
       int initialInputBufferSize,
-      ExoMediaCrypto exoMediaCrypto,
+      @Nullable ExoMediaCrypto exoMediaCrypto,
       boolean disableLoopFilter,
       boolean enableRowMultiThreadMode,
       int threads)
@@ -170,9 +170,19 @@ import java.nio.ByteBuffer;
 
   private native long vpxClose(long context);
   private native long vpxDecode(long context, ByteBuffer encoded, int length);
-  private native long vpxSecureDecode(long context, ByteBuffer encoded, int length,
-      ExoMediaCrypto mediaCrypto, int inputMode, byte[] key, byte[] iv,
-      int numSubSamples, int[] numBytesOfClearData, int[] numBytesOfEncryptedData);
+
+  private native long vpxSecureDecode(
+      long context,
+      ByteBuffer encoded,
+      int length,
+      @Nullable ExoMediaCrypto mediaCrypto,
+      int inputMode,
+      byte[] key,
+      byte[] iv,
+      int numSubSamples,
+      int[] numBytesOfClearData,
+      int[] numBytesOfEncryptedData);
+
   private native int vpxGetFrame(long context, VpxOutputBuffer outputBuffer);
 
   /**
diff --git a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxVideoSurfaceView.java b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxVideoSurfaceView.java
index 8c765952e7..4e983cccc7 100644
--- a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxVideoSurfaceView.java
+++ b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/VpxVideoSurfaceView.java
@@ -17,6 +17,7 @@ package com.google.android.exoplayer2.ext.vp9;
 
 import android.content.Context;
 import android.opengl.GLSurfaceView;
+import androidx.annotation.Nullable;
 import android.util.AttributeSet;
 
 /**
@@ -27,10 +28,10 @@ public class VpxVideoSurfaceView extends GLSurfaceView implements VpxOutputBuffe
   private final VpxRenderer renderer;
 
   public VpxVideoSurfaceView(Context context) {
-    this(context, null);
+    this(context, /* attrs= */ null);
   }
 
-  public VpxVideoSurfaceView(Context context, AttributeSet attrs) {
+  public VpxVideoSurfaceView(Context context, @Nullable AttributeSet attrs) {
     super(context, attrs);
     renderer = new VpxRenderer();
     setPreserveEGLContextOnPause(true);
diff --git a/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/package-info.java b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/package-info.java
new file mode 100644
index 0000000000..b8725607a5
--- /dev/null
+++ b/extensions/vp9/src/main/java/com/google/android/exoplayer2/ext/vp9/package-info.java
@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+@NonNullApi
+package com.google.android.exoplayer2.ext.vp9;
+
+import com.google.android.exoplayer2.util.NonNullApi;