diff --git a/libraries/muxer/src/main/java/androidx/media3/muxer/MetadataCollector.java b/libraries/muxer/src/main/java/androidx/media3/muxer/MetadataCollector.java
index 0863405733..cb90e1394f 100644
--- a/libraries/muxer/src/main/java/androidx/media3/muxer/MetadataCollector.java
+++ b/libraries/muxer/src/main/java/androidx/media3/muxer/MetadataCollector.java
@@ -23,22 +23,22 @@ import androidx.media3.container.Mp4LocationData;
 import androidx.media3.container.Mp4OrientationData;
 import androidx.media3.container.Mp4TimestampData;
 import androidx.media3.container.XmpData;
-import java.util.ArrayList;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
 import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
 
 /** Collects and provides metadata: location, FPS, XMP data, etc. */
 /* package */ final class MetadataCollector {
   public Mp4OrientationData orientationData;
   public @MonotonicNonNull Mp4LocationData locationData;
-  public List<MdtaMetadataEntry> metadataEntries;
+  public Set<MdtaMetadataEntry> metadataEntries;
   public Mp4TimestampData timestampData;
   public @MonotonicNonNull XmpData xmpData;
 
   /** Creates an instance. */
   public MetadataCollector() {
     orientationData = new Mp4OrientationData(/* orientation= */ 0);
-    metadataEntries = new ArrayList<>();
+    metadataEntries = new HashSet<>();
     long currentTimeInMp4TimeSeconds = unixTimeToMp4TimeSeconds(System.currentTimeMillis());
     timestampData =
         new Mp4TimestampData(