diff --git a/library/src/androidTest/java/com/google/android/exoplayer/drm/DrmInitDataTest.java b/library/src/androidTest/java/com/google/android/exoplayer/drm/DrmInitDataTest.java
index 83d9f93b79..20146ecb9d 100644
--- a/library/src/androidTest/java/com/google/android/exoplayer/drm/DrmInitDataTest.java
+++ b/library/src/androidTest/java/com/google/android/exoplayer/drm/DrmInitDataTest.java
@@ -15,8 +15,8 @@
  */
 package com.google.android.exoplayer.drm;
 
-import static com.google.android.exoplayer.drm.StreamingDrmSessionManager.PLAYREADY_UUID;
-import static com.google.android.exoplayer.drm.StreamingDrmSessionManager.WIDEVINE_UUID;
+import static com.google.android.exoplayer.C.PLAYREADY_UUID;
+import static com.google.android.exoplayer.C.WIDEVINE_UUID;
 import static com.google.android.exoplayer.util.MimeTypes.VIDEO_MP4;
 
 import com.google.android.exoplayer.C;
diff --git a/library/src/main/java/com/google/android/exoplayer/C.java b/library/src/main/java/com/google/android/exoplayer/C.java
index 3b80799309..5df0e03f66 100644
--- a/library/src/main/java/com/google/android/exoplayer/C.java
+++ b/library/src/main/java/com/google/android/exoplayer/C.java
@@ -26,196 +26,209 @@ import java.util.UUID;
 /**
  * Defines constants that are generally useful throughout the library.
  */
-public final class C {
+public interface C {
 
   /**
    * Special microsecond constant representing the end of a source.
    */
-  public static final long END_OF_SOURCE_US = Long.MIN_VALUE;
+  long END_OF_SOURCE_US = Long.MIN_VALUE;
 
   /**
    * Special microsecond constant representing an unset or unknown time or duration.
    */
-  public static final long UNSET_TIME_US = Long.MIN_VALUE + 1;
+  long UNSET_TIME_US = Long.MIN_VALUE + 1;
 
   /**
    * The number of microseconds in one second.
    */
-  public static final long MICROS_PER_SECOND = 1000000L;
+  long MICROS_PER_SECOND = 1000000L;
 
   /**
    * Represents an unbounded length of data.
    */
-  public static final int LENGTH_UNBOUNDED = -1;
+  int LENGTH_UNBOUNDED = -1;
 
   /**
    * The name of the UTF-8 charset.
    */
-  public static final String UTF8_NAME = "UTF-8";
+  String UTF8_NAME = "UTF-8";
 
   /**
    * @see MediaCodec#CRYPTO_MODE_AES_CTR
    */
   @SuppressWarnings("InlinedApi")
-  public static final int CRYPTO_MODE_AES_CTR = MediaCodec.CRYPTO_MODE_AES_CTR;
+  int CRYPTO_MODE_AES_CTR = MediaCodec.CRYPTO_MODE_AES_CTR;
 
   /**
    * @see AudioFormat#ENCODING_INVALID
    */
-  public static final int ENCODING_INVALID = AudioFormat.ENCODING_INVALID;
+  int ENCODING_INVALID = AudioFormat.ENCODING_INVALID;
 
   /**
    * @see AudioFormat#ENCODING_PCM_8BIT
    */
-  public static final int ENCODING_PCM_8BIT = AudioFormat.ENCODING_PCM_8BIT;
+  int ENCODING_PCM_8BIT = AudioFormat.ENCODING_PCM_8BIT;
 
   /**
    * @see AudioFormat#ENCODING_PCM_16BIT
    */
-  public static final int ENCODING_PCM_16BIT = AudioFormat.ENCODING_PCM_16BIT;
+  int ENCODING_PCM_16BIT = AudioFormat.ENCODING_PCM_16BIT;
 
   /**
    * PCM encoding with 24 bits per sample.
    */
-  public static final int ENCODING_PCM_24BIT = 0x80000000;
+  int ENCODING_PCM_24BIT = 0x80000000;
 
   /**
    * PCM encoding with 32 bits per sample.
    */
-  public static final int ENCODING_PCM_32BIT = 0x40000000;
+  int ENCODING_PCM_32BIT = 0x40000000;
 
   /**
    * @see AudioFormat#ENCODING_AC3
    */
   @SuppressWarnings("InlinedApi")
-  public static final int ENCODING_AC3 = AudioFormat.ENCODING_AC3;
+  int ENCODING_AC3 = AudioFormat.ENCODING_AC3;
 
   /**
    * @see AudioFormat#ENCODING_E_AC3
    */
   @SuppressWarnings("InlinedApi")
-  public static final int ENCODING_E_AC3 = AudioFormat.ENCODING_E_AC3;
+  int ENCODING_E_AC3 = AudioFormat.ENCODING_E_AC3;
 
   /**
    * @see AudioFormat#ENCODING_DTS
    */
   @SuppressWarnings("InlinedApi")
-  public static final int ENCODING_DTS = AudioFormat.ENCODING_DTS;
+  int ENCODING_DTS = AudioFormat.ENCODING_DTS;
 
   /**
    * @see AudioFormat#ENCODING_DTS_HD
    */
   @SuppressWarnings("InlinedApi")
-  public static final int ENCODING_DTS_HD = AudioFormat.ENCODING_DTS_HD;
+  int ENCODING_DTS_HD = AudioFormat.ENCODING_DTS_HD;
 
   /**
    * @see AudioFormat#CHANNEL_OUT_7POINT1_SURROUND
    */
   @SuppressWarnings({"InlinedApi", "deprecation"})
-  public static final int CHANNEL_OUT_7POINT1_SURROUND = Util.SDK_INT < 23
+  int CHANNEL_OUT_7POINT1_SURROUND = Util.SDK_INT < 23
       ? AudioFormat.CHANNEL_OUT_7POINT1 : AudioFormat.CHANNEL_OUT_7POINT1_SURROUND;
 
   /**
    * Indicates that a buffer holds a synchronization sample.
    */
   @SuppressWarnings("InlinedApi")
-  public static final int BUFFER_FLAG_KEY_FRAME = MediaCodec.BUFFER_FLAG_KEY_FRAME;
+  int BUFFER_FLAG_KEY_FRAME = MediaCodec.BUFFER_FLAG_KEY_FRAME;
 
   /**
    * Flag for empty buffers that signal that the end of the stream was reached.
    */
   @SuppressWarnings("InlinedApi")
-  public static final int BUFFER_FLAG_END_OF_STREAM = MediaCodec.BUFFER_FLAG_END_OF_STREAM;
+  int BUFFER_FLAG_END_OF_STREAM = MediaCodec.BUFFER_FLAG_END_OF_STREAM;
 
   /**
    * Indicates that a buffer is (at least partially) encrypted.
    */
-  public static final int BUFFER_FLAG_ENCRYPTED = 0x40000000;
+  int BUFFER_FLAG_ENCRYPTED = 0x40000000;
 
   /**
    * Indicates that a buffer should be decoded but not rendered.
    */
-  public static final int BUFFER_FLAG_DECODE_ONLY = 0x80000000;
+  int BUFFER_FLAG_DECODE_ONLY = 0x80000000;
 
   /**
    * A return value for methods where the end of an input was encountered.
    */
-  public static final int RESULT_END_OF_INPUT = -1;
+  int RESULT_END_OF_INPUT = -1;
 
   /**
    * A return value for methods where the length of parsed data exceeds the maximum length allowed.
    */
-  public static final int RESULT_MAX_LENGTH_EXCEEDED = -2;
+  int RESULT_MAX_LENGTH_EXCEEDED = -2;
 
   /**
    * A type constant for tracks of unknown type.
    */
-  public static final int TRACK_TYPE_UNKNOWN = -1;
+  int TRACK_TYPE_UNKNOWN = -1;
 
   /**
    * A type constant for tracks of some default type, where the type itself is unknown.
    */
-  public static final int TRACK_TYPE_DEFAULT = 0;
+  int TRACK_TYPE_DEFAULT = 0;
 
   /**
    * A type constant for audio tracks.
    */
-  public static final int TRACK_TYPE_AUDIO = 1;
+  int TRACK_TYPE_AUDIO = 1;
 
   /**
    * A type constant for video tracks.
    */
-  public static final int TRACK_TYPE_VIDEO = 2;
+  int TRACK_TYPE_VIDEO = 2;
 
   /**
    * A type constant for text tracks.
    */
-  public static final int TRACK_TYPE_TEXT = 3;
+  int TRACK_TYPE_TEXT = 3;
 
   /**
    * A type constant for metadata tracks.
    */
-  public static final int TRACK_TYPE_METADATA = 4;
+  int TRACK_TYPE_METADATA = 4;
 
   /**
   * A default size in bytes for an individual allocation that forms part of a larger buffer.
   */
-  public static final int DEFAULT_BUFFER_SEGMENT_SIZE = 64 * 1024;
+  int DEFAULT_BUFFER_SEGMENT_SIZE = 64 * 1024;
 
   /**
    * A default size in bytes for a video buffer.
    */
-  public static final int DEFAULT_VIDEO_BUFFER_SIZE = 200 * DEFAULT_BUFFER_SEGMENT_SIZE;
+  int DEFAULT_VIDEO_BUFFER_SIZE = 200 * DEFAULT_BUFFER_SEGMENT_SIZE;
 
   /**
    * A default size in bytes for an audio buffer.
    */
-  public static final int DEFAULT_AUDIO_BUFFER_SIZE = 54 * DEFAULT_BUFFER_SEGMENT_SIZE;
+  int DEFAULT_AUDIO_BUFFER_SIZE = 54 * DEFAULT_BUFFER_SEGMENT_SIZE;
 
   /**
    * A default size in bytes for a text buffer.
    */
-  public static final int DEFAULT_TEXT_BUFFER_SIZE = 2 * DEFAULT_BUFFER_SEGMENT_SIZE;
+  int DEFAULT_TEXT_BUFFER_SIZE = 2 * DEFAULT_BUFFER_SEGMENT_SIZE;
 
   /**
    * A default size in bytes for a muxed buffer (e.g. containing video, audio and text).
    */
-  public static final int DEFAULT_MUXED_BUFFER_SIZE = DEFAULT_VIDEO_BUFFER_SIZE
+  int DEFAULT_MUXED_BUFFER_SIZE = DEFAULT_VIDEO_BUFFER_SIZE
       + DEFAULT_AUDIO_BUFFER_SIZE + DEFAULT_TEXT_BUFFER_SIZE;
 
   /**
    * The Nil UUID as defined by
    * <a href="https://tools.ietf.org/html/rfc4122#section-4.1.7">RFC4122</a>.
    */
-  public static final UUID UUID_NIL = new UUID(0L, 0L);
+  UUID UUID_NIL = new UUID(0L, 0L);
+
+  /**
+   * UUID for the Widevine DRM scheme.
+   * <p></p>
+   * Widevine is supported on Android devices running Android 4.3 (API Level 18) and up.
+   */
+  UUID WIDEVINE_UUID = new UUID(0xEDEF8BA979D64ACEL, 0xA3C827DCD51D21EDL);
+
+  /**
+   * UUID for the PlayReady DRM scheme.
+   * <p>
+   * PlayReady is supported on all AndroidTV devices. Note that most other Android devices do not
+   * provide PlayReady support.
+   */
+  UUID PLAYREADY_UUID = new UUID(0x9A04F07998404286L, 0xAB92E65BE0885F95L);
 
   /**
    * The type of a message that can be passed to an video {@link TrackRenderer} via
    * {@link ExoPlayer#sendMessage} or {@link ExoPlayer#blockingSendMessage}. The message object
    * should be the target {@link Surface}, or null.
    */
-  public static final int MSG_SET_SURFACE = 1;
-
-  private C() {}
+  int MSG_SET_SURFACE = 1;
 
 }
diff --git a/library/src/main/java/com/google/android/exoplayer/drm/StreamingDrmSessionManager.java b/library/src/main/java/com/google/android/exoplayer/drm/StreamingDrmSessionManager.java
index 59539ee67c..0d64d81320 100644
--- a/library/src/main/java/com/google/android/exoplayer/drm/StreamingDrmSessionManager.java
+++ b/library/src/main/java/com/google/android/exoplayer/drm/StreamingDrmSessionManager.java
@@ -15,6 +15,7 @@
  */
 package com.google.android.exoplayer.drm;
 
+import com.google.android.exoplayer.C;
 import com.google.android.exoplayer.drm.DrmInitData.SchemeData;
 import com.google.android.exoplayer.extractor.mp4.PsshAtomUtil;
 import com.google.android.exoplayer.util.Util;
@@ -65,19 +66,6 @@ public class StreamingDrmSessionManager implements DrmSessionManager {
 
   }
 
-  /**
-   * UUID for the Widevine DRM scheme.
-   */
-  public static final UUID WIDEVINE_UUID = new UUID(0xEDEF8BA979D64ACEL, 0xA3C827DCD51D21EDL);
-
-  /**
-   * UUID for the PlayReady DRM scheme.
-   * <p>
-   * Note that PlayReady is unsupported by most Android devices, with the exception of Android TV
-   * devices, which do provide support.
-   */
-  public static final UUID PLAYREADY_UUID = new UUID(0x9A04F07998404286L, 0xAB92E65BE0885F95L);
-
   /**
    * The key to use when passing CustomData to a PlayReady instance in an optional parameter map.
    */
@@ -123,7 +111,7 @@ public class StreamingDrmSessionManager implements DrmSessionManager {
   public static StreamingDrmSessionManager newWidevineInstance(Looper playbackLooper,
       MediaDrmCallback callback, HashMap<String, String> optionalKeyRequestParameters,
       Handler eventHandler, EventListener eventListener) throws UnsupportedDrmException {
-    return new StreamingDrmSessionManager(WIDEVINE_UUID, playbackLooper, callback,
+    return new StreamingDrmSessionManager(C.WIDEVINE_UUID, playbackLooper, callback,
         optionalKeyRequestParameters, eventHandler, eventListener);
   }
 
@@ -152,7 +140,7 @@ public class StreamingDrmSessionManager implements DrmSessionManager {
     } else {
       optionalKeyRequestParameters = null;
     }
-    return new StreamingDrmSessionManager(PLAYREADY_UUID, playbackLooper, callback,
+    return new StreamingDrmSessionManager(C.PLAYREADY_UUID, playbackLooper, callback,
         optionalKeyRequestParameters, eventHandler, eventListener);
   }
 
@@ -281,11 +269,11 @@ public class StreamingDrmSessionManager implements DrmSessionManager {
       }
       if (Util.SDK_INT < 21) {
         // Prior to L the Widevine CDM required data to be extracted from the PSSH atom.
-        byte[] psshData = PsshAtomUtil.parseSchemeSpecificData(schemeData.data, WIDEVINE_UUID);
+        byte[] psshData = PsshAtomUtil.parseSchemeSpecificData(schemeData.data, C.WIDEVINE_UUID);
         if (psshData == null) {
           // Extraction failed. schemeData isn't a Widevine PSSH atom, so leave it unchanged.
         } else {
-          schemeData = new SchemeData(WIDEVINE_UUID, schemeData.mimeType, psshData);
+          schemeData = new SchemeData(C.WIDEVINE_UUID, schemeData.mimeType, psshData);
         }
       }
     }