diff --git a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ClippingMediaSourceTest.java b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ClippingMediaSourceTest.java
index c72188ad2c..6b17bf1e40 100644
--- a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ClippingMediaSourceTest.java
+++ b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ClippingMediaSourceTest.java
@@ -21,11 +21,13 @@ import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.Timeline.Period;
 import com.google.android.exoplayer2.Timeline.Window;
+import com.google.android.exoplayer2.source.ClippingMediaSource.IllegalClippingException;
 import com.google.android.exoplayer2.testutil.FakeMediaSource;
 import com.google.android.exoplayer2.testutil.FakeTimeline;
 import com.google.android.exoplayer2.testutil.FakeTimeline.TimelineWindowDefinition;
 import com.google.android.exoplayer2.testutil.MediaSourceTestRunner;
 import com.google.android.exoplayer2.testutil.TimelineAsserts;
+import java.io.IOException;
 
 /**
  * Unit tests for {@link ClippingMediaSource}.
@@ -40,11 +42,12 @@ public final class ClippingMediaSourceTest extends InstrumentationTestCase {
 
   @Override
   protected void setUp() throws Exception {
+    super.setUp();
     window = new Timeline.Window();
     period = new Timeline.Period();
   }
 
-  public void testNoClipping() {
+  public void testNoClipping() throws IOException {
     Timeline timeline = new SinglePeriodTimeline(C.msToUs(TEST_PERIOD_DURATION_US), true, false);
 
     Timeline clippedTimeline = getClippedTimeline(timeline, 0, TEST_PERIOD_DURATION_US);
@@ -55,7 +58,7 @@ public final class ClippingMediaSourceTest extends InstrumentationTestCase {
     assertEquals(TEST_PERIOD_DURATION_US, clippedTimeline.getPeriod(0, period).getDurationUs());
   }
 
-  public void testClippingUnseekableWindowThrows() {
+  public void testClippingUnseekableWindowThrows() throws IOException {
     Timeline timeline = new SinglePeriodTimeline(C.msToUs(TEST_PERIOD_DURATION_US), false, false);
 
     // If the unseekable window isn't clipped, clipping succeeds.
@@ -64,12 +67,12 @@ public final class ClippingMediaSourceTest extends InstrumentationTestCase {
       // If the unseekable window is clipped, clipping fails.
       getClippedTimeline(timeline, 1, TEST_PERIOD_DURATION_US);
       fail("Expected clipping to fail.");
-    } catch (IllegalArgumentException e) {
-      // Expected.
+    } catch (IllegalClippingException e) {
+      assertEquals(IllegalClippingException.REASON_NOT_SEEKABLE_TO_START, e.reason);
     }
   }
 
-  public void testClippingStart() {
+  public void testClippingStart() throws IOException {
     Timeline timeline = new SinglePeriodTimeline(C.msToUs(TEST_PERIOD_DURATION_US), true, false);
 
     Timeline clippedTimeline = getClippedTimeline(timeline, TEST_CLIP_AMOUNT_US,
@@ -80,7 +83,7 @@ public final class ClippingMediaSourceTest extends InstrumentationTestCase {
         clippedTimeline.getPeriod(0, period).getDurationUs());
   }
 
-  public void testClippingEnd() {
+  public void testClippingEnd() throws IOException {
     Timeline timeline = new SinglePeriodTimeline(C.msToUs(TEST_PERIOD_DURATION_US), true, false);
 
     Timeline clippedTimeline = getClippedTimeline(timeline, 0,
@@ -91,7 +94,7 @@ public final class ClippingMediaSourceTest extends InstrumentationTestCase {
         clippedTimeline.getPeriod(0, period).getDurationUs());
   }
 
-  public void testClippingStartAndEnd() {
+  public void testClippingStartAndEnd() throws IOException {
     Timeline timeline = new SinglePeriodTimeline(C.msToUs(TEST_PERIOD_DURATION_US), true, false);
 
     Timeline clippedTimeline = getClippedTimeline(timeline, TEST_CLIP_AMOUNT_US,
@@ -102,7 +105,7 @@ public final class ClippingMediaSourceTest extends InstrumentationTestCase {
         clippedTimeline.getPeriod(0, period).getDurationUs());
   }
 
-  public void testWindowAndPeriodIndices() {
+  public void testWindowAndPeriodIndices() throws IOException {
     Timeline timeline = new FakeTimeline(
         new TimelineWindowDefinition(1, 111, true, false, TEST_PERIOD_DURATION_US));
     Timeline clippedTimeline = getClippedTimeline(timeline, TEST_CLIP_AMOUNT_US,
@@ -122,7 +125,8 @@ public final class ClippingMediaSourceTest extends InstrumentationTestCase {
   /**
    * Wraps the specified timeline in a {@link ClippingMediaSource} and returns the clipped timeline.
    */
-  private static Timeline getClippedTimeline(Timeline timeline, long startMs, long endMs) {
+  private static Timeline getClippedTimeline(Timeline timeline, long startMs, long endMs)
+      throws IOException {
     FakeMediaSource fakeMediaSource = new FakeMediaSource(timeline, null);
     ClippingMediaSource mediaSource = new ClippingMediaSource(fakeMediaSource, startMs, endMs);
     MediaSourceTestRunner testRunner = new MediaSourceTestRunner(mediaSource, null);
diff --git a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ConcatenatingMediaSourceTest.java b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ConcatenatingMediaSourceTest.java
index 1ca32be46d..71c4b71023 100644
--- a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ConcatenatingMediaSourceTest.java
+++ b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/ConcatenatingMediaSourceTest.java
@@ -25,6 +25,7 @@ import com.google.android.exoplayer2.testutil.FakeTimeline;
 import com.google.android.exoplayer2.testutil.FakeTimeline.TimelineWindowDefinition;
 import com.google.android.exoplayer2.testutil.MediaSourceTestRunner;
 import com.google.android.exoplayer2.testutil.TimelineAsserts;
+import java.io.IOException;
 import junit.framework.TestCase;
 
 /**
@@ -32,7 +33,7 @@ import junit.framework.TestCase;
  */
 public final class ConcatenatingMediaSourceTest extends TestCase {
 
-  public void testEmptyConcatenation() {
+  public void testEmptyConcatenation() throws IOException {
     for (boolean atomic : new boolean[] {false, true}) {
       Timeline timeline = getConcatenatedTimeline(atomic);
       TimelineAsserts.assertEmpty(timeline);
@@ -45,7 +46,7 @@ public final class ConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testSingleMediaSource() {
+  public void testSingleMediaSource() throws IOException {
     Timeline timeline = getConcatenatedTimeline(false, createFakeTimeline(3, 111));
     TimelineAsserts.assertWindowIds(timeline, 111);
     TimelineAsserts.assertPeriodCounts(timeline, 3);
@@ -75,7 +76,7 @@ public final class ConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testMultipleMediaSources() {
+  public void testMultipleMediaSources() throws IOException {
     Timeline[] timelines = { createFakeTimeline(3, 111), createFakeTimeline(1, 222),
         createFakeTimeline(3, 333) };
     Timeline timeline = getConcatenatedTimeline(false, timelines);
@@ -121,7 +122,7 @@ public final class ConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testNestedMediaSources() {
+  public void testNestedMediaSources() throws IOException {
     Timeline timeline = getConcatenatedTimeline(false,
         getConcatenatedTimeline(false, createFakeTimeline(1, 111), createFakeTimeline(1, 222)),
         getConcatenatedTimeline(true, createFakeTimeline(1, 333), createFakeTimeline(1, 444)));
@@ -149,7 +150,7 @@ public final class ConcatenatingMediaSourceTest extends TestCase {
     TimelineAsserts.assertNextWindowIndices(timeline, Player.REPEAT_MODE_ALL, true, 2, 0, 3, 1);
   }
 
-  public void testEmptyTimelineMediaSources() {
+  public void testEmptyTimelineMediaSources() throws IOException {
     // Empty timelines in the front, back, and the middle (single and multiple in a row).
     Timeline[] timelines = { Timeline.EMPTY, createFakeTimeline(1, 111), Timeline.EMPTY,
         Timeline.EMPTY, createFakeTimeline(2, 222), Timeline.EMPTY, createFakeTimeline(3, 333),
@@ -197,7 +198,7 @@ public final class ConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testPeriodCreationWithAds() throws InterruptedException {
+  public void testPeriodCreationWithAds() throws IOException, InterruptedException {
     // Create media source with ad child source.
     Timeline timelineContentOnly = new FakeTimeline(
         new TimelineWindowDefinition(2, 111, true, false, 10 * C.MICROS_PER_SECOND));
@@ -231,7 +232,7 @@ public final class ConcatenatingMediaSourceTest extends TestCase {
    * the concatenated timeline.
    */
   private static Timeline getConcatenatedTimeline(boolean isRepeatOneAtomic,
-      Timeline... timelines) {
+      Timeline... timelines) throws IOException {
     MediaSource[] mediaSources = new MediaSource[timelines.length];
     for (int i = 0; i < timelines.length; i++) {
       mediaSources[i] = new FakeMediaSource(timelines[i], null);
diff --git a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/DynamicConcatenatingMediaSourceTest.java b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/DynamicConcatenatingMediaSourceTest.java
index 16c9e1a17c..5fa158725d 100644
--- a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/DynamicConcatenatingMediaSourceTest.java
+++ b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/DynamicConcatenatingMediaSourceTest.java
@@ -30,6 +30,7 @@ import com.google.android.exoplayer2.testutil.FakeTimeline;
 import com.google.android.exoplayer2.testutil.FakeTimeline.TimelineWindowDefinition;
 import com.google.android.exoplayer2.testutil.MediaSourceTestRunner;
 import com.google.android.exoplayer2.testutil.TimelineAsserts;
+import java.io.IOException;
 import java.util.Arrays;
 import junit.framework.TestCase;
 import org.mockito.Mockito;
@@ -55,7 +56,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     testRunner.release();
   }
 
-  public void testPlaylistChangesAfterPreparation() {
+  public void testPlaylistChangesAfterPreparation() throws IOException {
     Timeline timeline = testRunner.prepareSource();
     TimelineAsserts.assertEmpty(timeline);
 
@@ -171,7 +172,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     childSources[3].assertReleased();
   }
 
-  public void testPlaylistChangesBeforePreparation() {
+  public void testPlaylistChangesBeforePreparation() throws IOException {
     FakeMediaSource[] childSources = createMediaSources(4);
     mediaSource.addMediaSource(childSources[0]);
     mediaSource.addMediaSource(childSources[1]);
@@ -201,7 +202,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testPlaylistWithLazyMediaSource() {
+  public void testPlaylistWithLazyMediaSource() throws IOException {
     // Create some normal (immediately preparing) sources and some lazy sources whose timeline
     // updates need to be triggered.
     FakeMediaSource[] fastSources = createMediaSources(2);
@@ -290,7 +291,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testEmptyTimelineMediaSource() {
+  public void testEmptyTimelineMediaSource() throws IOException {
     Timeline timeline = testRunner.prepareSource();
     TimelineAsserts.assertEmpty(timeline);
 
@@ -426,7 +427,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     verify(runnable).run();
   }
 
-  public void testCustomCallbackAfterPreparationAddSingle() {
+  public void testCustomCallbackAfterPreparationAddSingle() throws IOException {
     DummyMainThread dummyMainThread = new DummyMainThread();
     try {
       testRunner.prepareSource();
@@ -444,7 +445,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testCustomCallbackAfterPreparationAddMultiple() {
+  public void testCustomCallbackAfterPreparationAddMultiple() throws IOException {
     DummyMainThread dummyMainThread = new DummyMainThread();
     try {
       testRunner.prepareSource();
@@ -464,7 +465,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testCustomCallbackAfterPreparationAddSingleWithIndex() {
+  public void testCustomCallbackAfterPreparationAddSingleWithIndex() throws IOException {
     DummyMainThread dummyMainThread = new DummyMainThread();
     try {
       testRunner.prepareSource();
@@ -482,7 +483,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testCustomCallbackAfterPreparationAddMultipleWithIndex() {
+  public void testCustomCallbackAfterPreparationAddMultipleWithIndex() throws IOException {
     DummyMainThread dummyMainThread = new DummyMainThread();
     try {
       testRunner.prepareSource();
@@ -502,7 +503,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testCustomCallbackAfterPreparationRemove() {
+  public void testCustomCallbackAfterPreparationRemove() throws IOException {
     DummyMainThread dummyMainThread = new DummyMainThread();
     try {
       testRunner.prepareSource();
@@ -528,7 +529,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testCustomCallbackAfterPreparationMove() {
+  public void testCustomCallbackAfterPreparationMove() throws IOException {
     DummyMainThread dummyMainThread = new DummyMainThread();
     try {
       testRunner.prepareSource();
@@ -556,7 +557,7 @@ public final class DynamicConcatenatingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testPeriodCreationWithAds() throws InterruptedException {
+  public void testPeriodCreationWithAds() throws IOException, InterruptedException {
     // Create dynamic media source with ad child source.
     Timeline timelineContentOnly = new FakeTimeline(
         new TimelineWindowDefinition(2, 111, true, false, 10 * C.MICROS_PER_SECOND));
diff --git a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/LoopingMediaSourceTest.java b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/LoopingMediaSourceTest.java
index 6f69923ea2..7648af195c 100644
--- a/library/core/src/androidTest/java/com/google/android/exoplayer2/source/LoopingMediaSourceTest.java
+++ b/library/core/src/androidTest/java/com/google/android/exoplayer2/source/LoopingMediaSourceTest.java
@@ -23,6 +23,7 @@ import com.google.android.exoplayer2.testutil.FakeTimeline;
 import com.google.android.exoplayer2.testutil.FakeTimeline.TimelineWindowDefinition;
 import com.google.android.exoplayer2.testutil.MediaSourceTestRunner;
 import com.google.android.exoplayer2.testutil.TimelineAsserts;
+import java.io.IOException;
 import junit.framework.TestCase;
 
 /**
@@ -39,7 +40,7 @@ public class LoopingMediaSourceTest extends TestCase {
         new TimelineWindowDefinition(1, 222), new TimelineWindowDefinition(1, 333));
   }
 
-  public void testSingleLoop() {
+  public void testSingleLoop() throws IOException {
     Timeline timeline = getLoopingTimeline(multiWindowTimeline, 1);
     TimelineAsserts.assertWindowIds(timeline, 111, 222, 333);
     TimelineAsserts.assertPeriodCounts(timeline, 1, 1, 1);
@@ -57,7 +58,7 @@ public class LoopingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testMultiLoop() {
+  public void testMultiLoop() throws IOException {
     Timeline timeline = getLoopingTimeline(multiWindowTimeline, 3);
     TimelineAsserts.assertWindowIds(timeline, 111, 222, 333, 111, 222, 333, 111, 222, 333);
     TimelineAsserts.assertPeriodCounts(timeline, 1, 1, 1, 1, 1, 1, 1, 1, 1);
@@ -77,7 +78,7 @@ public class LoopingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testInfiniteLoop() {
+  public void testInfiniteLoop() throws IOException {
     Timeline timeline = getLoopingTimeline(multiWindowTimeline, Integer.MAX_VALUE);
     TimelineAsserts.assertWindowIds(timeline, 111, 222, 333);
     TimelineAsserts.assertPeriodCounts(timeline, 1, 1, 1);
@@ -94,7 +95,7 @@ public class LoopingMediaSourceTest extends TestCase {
     }
   }
 
-  public void testEmptyTimelineLoop() {
+  public void testEmptyTimelineLoop() throws IOException {
     Timeline timeline = getLoopingTimeline(Timeline.EMPTY, 1);
     TimelineAsserts.assertEmpty(timeline);
 
@@ -109,7 +110,7 @@ public class LoopingMediaSourceTest extends TestCase {
    * Wraps the specified timeline in a {@link LoopingMediaSource} and returns
    * the looping timeline.
    */
-  private static Timeline getLoopingTimeline(Timeline timeline, int loopCount) {
+  private static Timeline getLoopingTimeline(Timeline timeline, int loopCount) throws IOException {
     FakeMediaSource fakeMediaSource = new FakeMediaSource(timeline, null);
     LoopingMediaSource mediaSource = new LoopingMediaSource(fakeMediaSource, loopCount);
     MediaSourceTestRunner testRunner = new MediaSourceTestRunner(mediaSource, null);
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 0b2ff33f30..721950f6b9 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
@@ -15,20 +15,68 @@
  */
 package com.google.android.exoplayer2.source;
 
+import android.support.annotation.IntDef;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.ExoPlayer;
 import com.google.android.exoplayer2.Timeline;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.util.Assertions;
 import java.io.IOException;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
 import java.util.ArrayList;
 
 /**
  * {@link MediaSource} that wraps a source and clips its timeline based on specified start/end
- * positions. The wrapped source may only have a single period/window.
+ * positions. The wrapped source must consist of a single period that starts at the beginning of the
+ * corresponding window.
  */
 public final class ClippingMediaSource implements MediaSource, MediaSource.Listener {
 
+  /**
+   * Thrown when a {@link ClippingMediaSource} cannot clip its wrapped source.
+   */
+  public static final class IllegalClippingException extends IOException {
+
+    /**
+     * The reason the clipping failed.
+     */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef({REASON_INVALID_PERIOD_COUNT, REASON_PERIOD_OFFSET_IN_WINDOW,
+        REASON_NOT_SEEKABLE_TO_START, REASON_START_EXCEEDS_END})
+    public @interface Reason {}
+    /**
+     * The wrapped source doesn't consist of a single period.
+     */
+    public static final int REASON_INVALID_PERIOD_COUNT = 0;
+    /**
+     * The wrapped source period doesn't start at the beginning of the corresponding window.
+     */
+    public static final int REASON_PERIOD_OFFSET_IN_WINDOW = 1;
+    /**
+     * The wrapped source is not seekable and a non-zero clipping start position was specified.
+     */
+    public static final int REASON_NOT_SEEKABLE_TO_START = 2;
+    /**
+     * The wrapped source ends before the specified clipping start position.
+     */
+    public static final int REASON_START_EXCEEDS_END = 3;
+
+    /**
+     * The reason clipping failed.
+     */
+    @Reason
+    public final int reason;
+
+    /**
+     * @param reason The reason clipping failed.
+     */
+    public IllegalClippingException(@Reason int reason) {
+      this.reason = reason;
+    }
+
+  }
+
   private final MediaSource mediaSource;
   private final long startUs;
   private final long endUs;
@@ -36,6 +84,7 @@ public final class ClippingMediaSource implements MediaSource, MediaSource.Liste
   private final ArrayList<ClippingMediaPeriod> mediaPeriods;
 
   private MediaSource.Listener sourceListener;
+  private IllegalClippingException clippingError;
 
   /**
    * Creates a new clipping source that wraps the specified source.
@@ -88,6 +137,9 @@ public final class ClippingMediaSource implements MediaSource, MediaSource.Liste
 
   @Override
   public void maybeThrowSourceInfoRefreshError() throws IOException {
+    if (clippingError != null) {
+      throw clippingError;
+    }
     mediaSource.maybeThrowSourceInfoRefreshError();
   }
 
@@ -115,8 +167,17 @@ public final class ClippingMediaSource implements MediaSource, MediaSource.Liste
 
   @Override
   public void onSourceInfoRefreshed(MediaSource source, Timeline timeline, Object manifest) {
-    sourceListener.onSourceInfoRefreshed(this, new ClippingTimeline(timeline, startUs, endUs),
-        manifest);
+    if (clippingError != null) {
+      return;
+    }
+    ClippingTimeline clippingTimeline;
+    try {
+      clippingTimeline = new ClippingTimeline(timeline, startUs, endUs);
+    } catch (IllegalClippingException e) {
+      clippingError = e;
+      return;
+    }
+    sourceListener.onSourceInfoRefreshed(this, clippingTimeline, manifest);
     int count = mediaPeriods.size();
     for (int i = 0; i < count; i++) {
       mediaPeriods.get(i).setClipping(startUs, endUs);
@@ -138,22 +199,30 @@ public final class ClippingMediaSource implements MediaSource, MediaSource.Liste
      * @param startUs The number of microseconds to clip from the start of {@code timeline}.
      * @param endUs The end position in microseconds for the clipped timeline relative to the start
      *     of {@code timeline}, or {@link C#TIME_END_OF_SOURCE} to clip no samples from the end.
+     * @throws IllegalClippingException If the timeline could not be clipped.
      */
-    public ClippingTimeline(Timeline timeline, long startUs, long endUs) {
+    public ClippingTimeline(Timeline timeline, long startUs, long endUs)
+        throws IllegalClippingException {
       super(timeline);
-      Assertions.checkArgument(timeline.getWindowCount() == 1);
-      Assertions.checkArgument(timeline.getPeriodCount() == 1);
+      if (timeline.getPeriodCount() != 1) {
+        throw new IllegalClippingException(IllegalClippingException.REASON_INVALID_PERIOD_COUNT);
+      }
+      if (timeline.getPeriod(0, new Period()).getPositionInWindowUs() != 0) {
+        throw new IllegalClippingException(IllegalClippingException.REASON_PERIOD_OFFSET_IN_WINDOW);
+      }
       Window window = timeline.getWindow(0, new Window(), false);
       long resolvedEndUs = endUs == C.TIME_END_OF_SOURCE ? window.durationUs : endUs;
       if (window.durationUs != C.TIME_UNSET) {
         if (resolvedEndUs > window.durationUs) {
           resolvedEndUs = window.durationUs;
         }
-        Assertions.checkArgument(startUs == 0 || window.isSeekable);
-        Assertions.checkArgument(startUs <= resolvedEndUs);
+        if (startUs != 0 && !window.isSeekable) {
+          throw new IllegalClippingException(IllegalClippingException.REASON_NOT_SEEKABLE_TO_START);
+        }
+        if (startUs > resolvedEndUs) {
+          throw new IllegalClippingException(IllegalClippingException.REASON_START_EXCEEDS_END);
+        }
       }
-      Period period = timeline.getPeriod(0, new Period());
-      Assertions.checkArgument(period.getPositionInWindowUs() == 0);
       this.startUs = startUs;
       this.endUs = resolvedEndUs;
     }
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 ea0274796f..3b468d8709 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
@@ -45,11 +45,11 @@ public final class MergingMediaSource implements MediaSource {
     @IntDef({REASON_WINDOWS_ARE_DYNAMIC, REASON_PERIOD_COUNT_MISMATCH})
     public @interface Reason {}
     /**
-     * The merge failed because one of the sources being merged has a dynamic window.
+     * One of the sources being merged has a dynamic window.
      */
     public static final int REASON_WINDOWS_ARE_DYNAMIC = 0;
     /**
-     * The merge failed because the sources have different period counts.
+     * The sources have different period counts.
      */
     public static final int REASON_PERIOD_COUNT_MISMATCH = 1;
 
diff --git a/testutils/src/main/java/com/google/android/exoplayer2/testutil/MediaSourceTestRunner.java b/testutils/src/main/java/com/google/android/exoplayer2/testutil/MediaSourceTestRunner.java
index 235c04bef5..4f31a8b027 100644
--- a/testutils/src/main/java/com/google/android/exoplayer2/testutil/MediaSourceTestRunner.java
+++ b/testutils/src/main/java/com/google/android/exoplayer2/testutil/MediaSourceTestRunner.java
@@ -32,7 +32,7 @@ import com.google.android.exoplayer2.source.MediaSource.MediaPeriodId;
 import com.google.android.exoplayer2.upstream.Allocator;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
-
+import java.io.IOException;
 import java.util.concurrent.LinkedBlockingDeque;
 import java.util.concurrent.TimeUnit;
 
@@ -100,13 +100,25 @@ public class MediaSourceTestRunner {
    *
    * @return The initial {@link Timeline}.
    */
-  public Timeline prepareSource() {
+  public Timeline prepareSource() throws IOException {
+    final IOException[] prepareError = new IOException[1];
     runOnPlaybackThread(new Runnable() {
       @Override
       public void run() {
         mediaSource.prepareSource(player, true, mediaSourceListener);
+        try {
+          // TODO: This only catches errors that are set synchronously in prepareSource. To capture
+          // async errors we'll need to poll maybeThrowSourceInfoRefreshError until the first call
+          // to onSourceInfoRefreshed.
+          mediaSource.maybeThrowSourceInfoRefreshError();
+        } catch (IOException e) {
+          prepareError[0] = e;
+        }
       }
     });
+    if (prepareError[0] != null) {
+      throw prepareError[0];
+    }
     return assertTimelineChangeBlocking();
   }