diff --git a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java
index 21c0fdfc7a..1f245784e7 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/source/chunk/ChunkSampleStream.java
@@ -79,6 +79,8 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
   private @Nullable ReleaseCallback<T> releaseCallback;
   private long pendingResetPositionUs;
   private long lastSeekPositionUs;
+  private int nextNotifyPrimaryFormatMediaChunkIndex;
+
   /* package */ long decodeOnlyUntilPositionUs;
   /* package */ boolean loadingFinished;
 
@@ -191,16 +193,16 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     if (isPendingReset()) {
       return;
     }
-    int oldFirstIndex = primarySampleQueue.getFirstIndex();
+    int oldFirstSampleIndex = primarySampleQueue.getFirstIndex();
     primarySampleQueue.discardTo(positionUs, toKeyframe, true);
-    int newFirstIndex = primarySampleQueue.getFirstIndex();
-    if (newFirstIndex > oldFirstIndex) {
+    int newFirstSampleIndex = primarySampleQueue.getFirstIndex();
+    if (newFirstSampleIndex > oldFirstSampleIndex) {
       long discardToUs = primarySampleQueue.getFirstTimestampUs();
       for (int i = 0; i < embeddedSampleQueues.length; i++) {
         embeddedSampleQueues[i].discardTo(discardToUs, toKeyframe, embeddedTracksSelected[i]);
       }
-      discardDownstreamMediaChunks(newFirstIndex);
     }
+    discardDownstreamMediaChunks(newFirstSampleIndex);
   }
 
   /**
@@ -318,7 +320,11 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     }
 
     if (seekInsideBuffer) {
-      // We can seek inside the buffer. Advance the embedded sample queues to the seek position.
+      // We can seek inside the buffer.
+      nextNotifyPrimaryFormatMediaChunkIndex =
+          primarySampleIndexToMediaChunkIndex(
+              primarySampleQueue.getReadIndex(), /* minChunkIndex= */ 0);
+      // Advance the embedded sample queues to the seek position.
       for (SampleQueue embeddedSampleQueue : embeddedSampleQueues) {
         embeddedSampleQueue.rewind();
         embeddedSampleQueue.advanceTo(positionUs, true, false);
@@ -328,6 +334,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
       pendingResetPositionUs = positionUs;
       loadingFinished = false;
       mediaChunks.clear();
+      nextNotifyPrimaryFormatMediaChunkIndex = 0;
       if (loader.isLoading()) {
         loader.cancelLoading();
       } else {
@@ -400,13 +407,9 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     if (isPendingReset()) {
       return C.RESULT_NOTHING_READ;
     }
-    int result =
-        primarySampleQueue.read(
-            formatHolder, buffer, formatRequired, loadingFinished, decodeOnlyUntilPositionUs);
-    if (result == C.RESULT_BUFFER_READ) {
-      maybeNotifyPrimaryTrackFormatChanged(primarySampleQueue.getReadIndex(), 1);
-    }
-    return result;
+    maybeNotifyPrimaryTrackFormatChanged();
+    return primarySampleQueue.read(
+        formatHolder, buffer, formatRequired, loadingFinished, decodeOnlyUntilPositionUs);
   }
 
   @Override
@@ -423,9 +426,7 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
         skipCount = 0;
       }
     }
-    if (skipCount > 0) {
-      maybeNotifyPrimaryTrackFormatChanged(primarySampleQueue.getReadIndex(), skipCount);
-    }
+    maybeNotifyPrimaryTrackFormatChanged();
     return skipCount;
   }
 
@@ -669,22 +670,25 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
     return pendingResetPositionUs != C.TIME_UNSET;
   }
 
-  private void discardDownstreamMediaChunks(int discardToPrimaryStreamIndex) {
+  private void discardDownstreamMediaChunks(int discardToSampleIndex) {
     int discardToMediaChunkIndex =
-        primaryStreamIndexToMediaChunkIndex(discardToPrimaryStreamIndex, /* minChunkIndex= */ 0);
+        primarySampleIndexToMediaChunkIndex(discardToSampleIndex, /* minChunkIndex= */ 0);
+    // Don't discard any chunks that we haven't reported the primary format change for yet.
+    discardToMediaChunkIndex =
+        Math.min(discardToMediaChunkIndex, nextNotifyPrimaryFormatMediaChunkIndex);
     if (discardToMediaChunkIndex > 0) {
       Util.removeRange(mediaChunks, /* fromIndex= */ 0, /* toIndex= */ discardToMediaChunkIndex);
+      nextNotifyPrimaryFormatMediaChunkIndex -= discardToMediaChunkIndex;
     }
   }
 
-  private void maybeNotifyPrimaryTrackFormatChanged(int toPrimaryStreamReadIndex, int readCount) {
-    int fromMediaChunkIndex = primaryStreamIndexToMediaChunkIndex(
-        toPrimaryStreamReadIndex - readCount, /* minChunkIndex= */ 0);
-    int toMediaChunkIndexInclusive = readCount == 1 ? fromMediaChunkIndex
-        : primaryStreamIndexToMediaChunkIndex(toPrimaryStreamReadIndex - 1,
-            /* minChunkIndex= */ fromMediaChunkIndex);
-    for (int i = fromMediaChunkIndex; i <= toMediaChunkIndexInclusive; i++) {
-      maybeNotifyPrimaryTrackFormatChanged(i);
+  private void maybeNotifyPrimaryTrackFormatChanged() {
+    int readSampleIndex = primarySampleQueue.getReadIndex();
+    int notifyToMediaChunkIndex =
+        primarySampleIndexToMediaChunkIndex(
+            readSampleIndex, /* minChunkIndex= */ nextNotifyPrimaryFormatMediaChunkIndex - 1);
+    while (nextNotifyPrimaryFormatMediaChunkIndex <= notifyToMediaChunkIndex) {
+      maybeNotifyPrimaryTrackFormatChanged(nextNotifyPrimaryFormatMediaChunkIndex++);
     }
   }
 
@@ -700,12 +704,20 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
   }
 
   /**
-   * Returns media chunk index for primary stream sample index. May be -1 if the list of media
-   * chunks is empty or the requested index is less than the first index in the first media chunk.
+   * Returns the media chunk index corresponding to a given primary sample index.
+   *
+   * @param primarySampleIndex The primary sample index for which the corresponding media chunk
+   *     index is required.
+   * @param minChunkIndex A minimum chunk index from which to start searching, or -1 if no hint can
+   *     be provided.
+   * @return The index of the media chunk corresponding to the sample index, or -1 if the list of
+   *     media chunks is empty, or {@code minChunkIndex} if the sample precedes the first chunk in
+   *     the search (i.e. the chunk at {@code minChunkIndex}, or at index 0 if {@code minChunkIndex}
+   *     is -1.
    */
-  private int primaryStreamIndexToMediaChunkIndex(int primaryStreamIndex, int minChunkIndex) {
+  private int primarySampleIndexToMediaChunkIndex(int primarySampleIndex, int minChunkIndex) {
     for (int i = minChunkIndex + 1; i < mediaChunks.size(); i++) {
-      if (mediaChunks.get(i).getFirstSampleIndex(0) > primaryStreamIndex) {
+      if (mediaChunks.get(i).getFirstSampleIndex(0) > primarySampleIndex) {
         return i - 1;
       }
     }
@@ -726,6 +738,8 @@ public class ChunkSampleStream<T extends ChunkSource> implements SampleStream, S
   private BaseMediaChunk discardUpstreamMediaChunksFromIndex(int chunkIndex) {
     BaseMediaChunk firstRemovedChunk = mediaChunks.get(chunkIndex);
     Util.removeRange(mediaChunks, /* fromIndex= */ chunkIndex, /* toIndex= */ mediaChunks.size());
+    nextNotifyPrimaryFormatMediaChunkIndex =
+        Math.max(nextNotifyPrimaryFormatMediaChunkIndex, mediaChunks.size());
     primarySampleQueue.discardUpstreamSamples(firstRemovedChunk.getFirstSampleIndex(0));
     for (int i = 0; i < embeddedSampleQueues.length; i++) {
       embeddedSampleQueues[i].discardUpstreamSamples(firstRemovedChunk.getFirstSampleIndex(i + 1));