Allow CmcdConfiguration.Factory to return null to disable CMCD

libraries/exoplayer/src/main/java/androidx/media3/exoplayer/upstream/CmcdConfiguration.java

@@ -127,8 +127,9 @@ public interface Factory {
      * Creates a {@link CmcdConfiguration} based on the provided {@link MediaItem}.
      *
      * @param mediaItem The {@link MediaItem} from which to create the CMCD configuration.
-     * @return A {@link CmcdConfiguration} instance.
+     * @return A {@link CmcdConfiguration} instance, or {@code null} to disable CMCD.
      */
+    @Nullable
     CmcdConfiguration createCmcdConfiguration(MediaItem mediaItem);
 
     /**

libraries/exoplayer/src/test/java/androidx/media3/exoplayer/upstream/CmcdConfigurationTest.java

@@ -18,6 +18,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static org.junit.Assert.assertThrows;
 
+import androidx.annotation.Nullable;
 import androidx.media3.common.C;
 import androidx.media3.common.MediaItem;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
@@ -134,4 +135,17 @@ public int getRequestedMaximumThroughputKbps(int throughputKbps) {
                 /* throughputKbps= */ 100))
         .isEqualTo(200);
   }
+
+  @Test
+  public void customFactory_returnsNull() {
+    CmcdConfiguration.Factory cmcdConfigurationFactory =
+        mediaItem -> null;
+    MediaItem mediaItem = new MediaItem.Builder().setMediaId(TEST_MEDIA_ID).build();
+
+    @Nullable
+    CmcdConfiguration cmcdConfiguration =
+        cmcdConfigurationFactory.createCmcdConfiguration(mediaItem);
+
+    assertThat(cmcdConfiguration).isNull();
+  }
 }

libraries/exoplayer_dash/src/main/java/androidx/media3/exoplayer/dash/DashMediaSource.java

@@ -113,7 +113,7 @@ public static final class Factory implements MediaSourceFactory {
     private final DashChunkSource.Factory chunkSourceFactory;
     @Nullable private final DataSource.Factory manifestDataSourceFactory;
 
-    private CmcdConfiguration.Factory cmcdConfigurationFactory;
+    @Nullable private CmcdConfiguration.Factory cmcdConfigurationFactory;
     private DrmSessionManagerProvider drmSessionManagerProvider;
     private CompositeSequenceableLoaderFactory compositeSequenceableLoaderFactory;
     private LoadErrorHandlingPolicy loadErrorHandlingPolicy;