diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/ClippingMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/ClippingMediaSource.java
index c3e700fff5..c942f9320e 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/ClippingMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/ClippingMediaSource.java
@@ -193,7 +193,7 @@ public final class ClippingMediaSource extends CompositeMediaSource<Void> {
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(mediaTransferListener);
     prepareChildSource(/* id= */ null, mediaSource);
   }
@@ -228,7 +228,7 @@ public final class ClippingMediaSource extends CompositeMediaSource<Void> {
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     super.releaseSourceInternal();
     clippingError = null;
     clippingTimeline = null;
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java
index 06db088f06..1a9e1ff250 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/CompositeMediaSource.java
@@ -44,7 +44,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
 
   @Override
   @CallSuper
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     this.mediaTransferListener = mediaTransferListener;
     eventHandler = new Handler();
   }
@@ -59,7 +59,7 @@ public abstract class CompositeMediaSource<T> extends BaseMediaSource {
 
   @Override
   @CallSuper
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     for (MediaSourceAndListener childSource : childSources.values()) {
       childSource.mediaSource.releaseSource(childSource.listener);
       childSource.mediaSource.removeEventListener(childSource.eventListener);
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/ExtractorMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/ExtractorMediaSource.java
index d9003e443e..f07ee63e79 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/ExtractorMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/ExtractorMediaSource.java
@@ -339,7 +339,7 @@ public final class ExtractorMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     progressiveMediaSource.prepareSource(/* listener= */ this, mediaTransferListener);
   }
 
@@ -359,7 +359,7 @@ public final class ExtractorMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     progressiveMediaSource.releaseSource(/* listener= */ this);
   }
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/LoopingMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/LoopingMediaSource.java
index 769f545aaa..7adb18dc94 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/LoopingMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/LoopingMediaSource.java
@@ -71,7 +71,7 @@ public final class LoopingMediaSource extends CompositeMediaSource<Void> {
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(mediaTransferListener);
     prepareChildSource(/* id= */ null, childSource);
   }
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/MergingMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/MergingMediaSource.java
index 7188cada0f..f12ce92f54 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/MergingMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/MergingMediaSource.java
@@ -104,7 +104,7 @@ public final class MergingMediaSource extends CompositeMediaSource<Integer> {
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(mediaTransferListener);
     for (int i = 0; i < mediaSources.length; i++) {
       prepareChildSource(i, mediaSources[i]);
@@ -140,7 +140,7 @@ public final class MergingMediaSource extends CompositeMediaSource<Integer> {
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     super.releaseSourceInternal();
     Arrays.fill(timelines, null);
     primaryManifest = null;
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java
index 5ed12154b3..ba69b46d7f 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/ProgressiveMediaSource.java
@@ -228,7 +228,7 @@ public final class ProgressiveMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     transferListener = mediaTransferListener;
     notifySourceInfoRefreshed(timelineDurationUs, timelineIsSeekable);
   }
@@ -262,7 +262,7 @@ public final class ProgressiveMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     // Do nothing.
   }
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/SilenceMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/SilenceMediaSource.java
index b03dd0ea7c..fc99e8cb7b 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/SilenceMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/SilenceMediaSource.java
@@ -66,7 +66,7 @@ public final class SilenceMediaSource extends BaseMediaSource {
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     refreshSourceInfo(
         new SinglePeriodTimeline(durationUs, /* isSeekable= */ true, /* isDynamic= */ false),
         /* manifest= */ null);
@@ -84,7 +84,7 @@ public final class SilenceMediaSource extends BaseMediaSource {
   public void releasePeriod(MediaPeriod mediaPeriod) {}
 
   @Override
-  public void releaseSourceInternal() {}
+  protected void releaseSourceInternal() {}
 
   private static final class SilenceMediaPeriod implements MediaPeriod {
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaSource.java
index 55d967cd69..6c1881a01a 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/SingleSampleMediaSource.java
@@ -302,7 +302,7 @@ public final class SingleSampleMediaSource extends BaseMediaSource {
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     transferListener = mediaTransferListener;
     refreshSourceInfo(timeline, /* manifest= */ null);
   }
@@ -331,7 +331,7 @@ public final class SingleSampleMediaSource extends BaseMediaSource {
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     // Do nothing.
   }
 
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/ads/AdsMediaSource.java b/library/core/src/main/java/com/google/android/exoplayer2/source/ads/AdsMediaSource.java
index dd4c0d26b2..a6c2cf2767 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/ads/AdsMediaSource.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/ads/AdsMediaSource.java
@@ -193,7 +193,7 @@ public final class AdsMediaSource extends CompositeMediaSource<MediaPeriodId> {
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     super.prepareSourceInternal(mediaTransferListener);
     ComponentListener componentListener = new ComponentListener();
     this.componentListener = componentListener;
@@ -259,7 +259,7 @@ public final class AdsMediaSource extends CompositeMediaSource<MediaPeriodId> {
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     super.releaseSourceInternal();
     Assertions.checkNotNull(componentListener).release();
     componentListener = null;
diff --git a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java
index 779a97fd09..551555502f 100644
--- a/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java
+++ b/library/dash/src/main/java/com/google/android/exoplayer2/source/dash/DashMediaSource.java
@@ -630,7 +630,7 @@ public final class DashMediaSource extends BaseMediaSource {
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     this.mediaTransferListener = mediaTransferListener;
     if (sideloadedManifest) {
       processManifest(false);
@@ -679,7 +679,7 @@ public final class DashMediaSource extends BaseMediaSource {
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     manifestLoadPending = false;
     dataSource = null;
     if (loader != null) {
diff --git a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java
index fbb6285d1d..f891670e78 100644
--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/HlsMediaSource.java
@@ -333,7 +333,7 @@ public final class HlsMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     this.mediaTransferListener = mediaTransferListener;
     EventDispatcher eventDispatcher = createEventDispatcher(/* mediaPeriodId= */ null);
     playlistTracker.start(manifestUri, eventDispatcher, /* listener= */ this);
@@ -366,7 +366,7 @@ public final class HlsMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     playlistTracker.stop();
   }
 
diff --git a/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java b/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java
index 3c18bfe644..e31fbccae5 100644
--- a/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java
+++ b/library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java
@@ -525,7 +525,7 @@ public final class SsMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
+  protected void prepareSourceInternal(@Nullable TransferListener mediaTransferListener) {
     this.mediaTransferListener = mediaTransferListener;
     if (sideloadedManifest) {
       manifestLoaderErrorThrower = new LoaderErrorThrower.Dummy();
@@ -568,7 +568,7 @@ public final class SsMediaSource extends BaseMediaSource
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     manifest = sideloadedManifest ? manifest : null;
     manifestDataSource = null;
     manifestLoadStartTimestamp = 0;
diff --git a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaSource.java b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaSource.java
index 0d50f22bc0..80456169ff 100644
--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaSource.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/FakeMediaSource.java
@@ -137,7 +137,7 @@ public class FakeMediaSource extends BaseMediaSource {
   }
 
   @Override
-  public void releaseSourceInternal() {
+  protected void releaseSourceInternal() {
     assertThat(preparedSource).isTrue();
     assertThat(releasedSource).isFalse();
     assertThat(activeMediaPeriods.isEmpty()).isTrue();