diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/BaseMediaChunk.java b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/BaseMediaChunk.java
index e3eae2b4d8..e872f730de 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/BaseMediaChunk.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/BaseMediaChunk.java
@@ -44,7 +44,7 @@ public abstract class BaseMediaChunk extends MediaChunk {
    * @param endTimeUs The end time of the media contained by the chunk, in microseconds.
    * @param seekTimeUs The media time from which output will begin, or {@link C#TIME_UNSET} if the
    *     whole chunk should be output.
-   * @param chunkIndex The index of the chunk.
+   * @param chunkIndex The index of the chunk, or {@link C#INDEX_UNSET} if it is not known.
    */
   public BaseMediaChunk(
       DataSource dataSource,
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ContainerMediaChunk.java b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ContainerMediaChunk.java
index ed73cf2588..6aa90e58e1 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ContainerMediaChunk.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ContainerMediaChunk.java
@@ -49,7 +49,7 @@ public class ContainerMediaChunk extends BaseMediaChunk {
    * @param endTimeUs The end time of the media contained by the chunk, in microseconds.
    * @param seekTimeUs The media time from which output will begin, or {@link C#TIME_UNSET} if the
    *     whole chunk should be output.
-   * @param chunkIndex The index of the chunk.
+   * @param chunkIndex The index of the chunk, or {@link C#INDEX_UNSET} if it is not known.
    * @param chunkCount The number of chunks in the underlying media that are spanned by this
    *     instance. Normally equal to one, but may be larger if multiple chunks as defined by the
    *     underlying media are being merged into a single load.
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/MediaChunk.java b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/MediaChunk.java
index d313a8cb81..9626f4b03f 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/MediaChunk.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/MediaChunk.java
@@ -26,7 +26,7 @@ import com.google.android.exoplayer2.util.Assertions;
  */
 public abstract class MediaChunk extends Chunk {
 
-  /** The chunk index. */
+  /** The chunk index, or {@link C#INDEX_UNSET} if it is not known. */
   public final long chunkIndex;
 
   /**
@@ -37,7 +37,7 @@ public abstract class MediaChunk extends Chunk {
    * @param trackSelectionData See {@link #trackSelectionData}.
    * @param startTimeUs The start time of the media contained by the chunk, in microseconds.
    * @param endTimeUs The end time of the media contained by the chunk, in microseconds.
-   * @param chunkIndex The index of the chunk.
+   * @param chunkIndex The index of the chunk, or {@link C#INDEX_UNSET} if it is not known.
    */
   public MediaChunk(
       DataSource dataSource,
@@ -54,9 +54,9 @@ public abstract class MediaChunk extends Chunk {
     this.chunkIndex = chunkIndex;
   }
 
-  /** Returns the next chunk index. */
+  /** Returns the next chunk index or {@link C#INDEX_UNSET} if it is not known. */
   public long getNextChunkIndex() {
-    return chunkIndex + 1;
+    return chunkIndex != C.INDEX_UNSET ? chunkIndex + 1 : C.INDEX_UNSET;
   }
 
   /**
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/SingleSampleMediaChunk.java b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/SingleSampleMediaChunk.java
index bd2363ede1..5247f9f973 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/SingleSampleMediaChunk.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/SingleSampleMediaChunk.java
@@ -45,7 +45,7 @@ public final class SingleSampleMediaChunk extends BaseMediaChunk {
    * @param trackSelectionData See {@link #trackSelectionData}.
    * @param startTimeUs The start time of the media contained by the chunk, in microseconds.
    * @param endTimeUs The end time of the media contained by the chunk, in microseconds.
-   * @param chunkIndex The index of the chunk.
+   * @param chunkIndex The index of the chunk, or {@link C#INDEX_UNSET} if it is not known.
    * @param trackType The type of the chunk. Typically one of the {@link C} {@code TRACK_TYPE_*}
    *     constants.
    * @param sampleFormat The {@link Format} of the sample in the chunk.