diff --git a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/MergingMediaPeriod.java b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/MergingMediaPeriod.java
index c71b5cffd0..1cf6a3734f 100644
--- a/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/MergingMediaPeriod.java
+++ b/libraries/exoplayer/src/main/java/androidx/media3/exoplayer/source/MergingMediaPeriod.java
@@ -118,17 +118,13 @@ import org.checkerframework.checker.nullness.qual.MonotonicNonNull;
     for (int i = 0; i < selections.length; i++) {
       Integer streamChildIndex = streams[i] == null ? null : streamPeriodIndices.get(streams[i]);
       streamChildIndices[i] = streamChildIndex == null ? C.INDEX_UNSET : streamChildIndex;
-      selectionChildIndices[i] = C.INDEX_UNSET;
       if (selections[i] != null) {
         TrackGroup mergedTrackGroup = selections[i].getTrackGroup();
-        TrackGroup childTrackGroup =
-            checkNotNull(childTrackGroupByMergedTrackGroup.get(mergedTrackGroup));
-        for (int j = 0; j < periods.length; j++) {
-          if (periods[j].getTrackGroups().indexOf(childTrackGroup) != C.INDEX_UNSET) {
-            selectionChildIndices[i] = j;
-            break;
-          }
-        }
+        // mergedTrackGroup.id is 'periods array index' + ":" + childTrackGroup.id
+        selectionChildIndices[i] =
+            Integer.parseInt(mergedTrackGroup.id.substring(0, mergedTrackGroup.id.indexOf(":")));
+      } else {
+        selectionChildIndices[i] = C.INDEX_UNSET;
       }
     }
     streamPeriodIndices.clear();
diff --git a/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/source/MergingMediaPeriodTest.java b/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/source/MergingMediaPeriodTest.java
index 740e468c23..2ef9252c64 100644
--- a/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/source/MergingMediaPeriodTest.java
+++ b/libraries/exoplayer/src/test/java/androidx/media3/exoplayer/source/MergingMediaPeriodTest.java
@@ -198,6 +198,39 @@ public final class MergingMediaPeriodTest {
     assertThat(firstSelectionChild2).isEqualTo(secondSelectionChild2);
   }
 
+  // https://github.com/google/ExoPlayer/issues/10930
+  @Test
+  public void selectTracks_withIdenticalFormats_selectsMatchingPeriod() throws Exception {
+    MergingMediaPeriod mergingMediaPeriod =
+        prepareMergingPeriod(
+            new MergingPeriodDefinition(
+                /* timeOffsetUs= */ 0, /* singleSampleTimeUs= */ 123_000, childFormat11),
+            new MergingPeriodDefinition(
+                /* timeOffsetUs= */ -3000, /* singleSampleTimeUs= */ 456_000, childFormat11));
+
+    ExoTrackSelection[] selectionArray = {
+      new FixedTrackSelection(mergingMediaPeriod.getTrackGroups().get(1), /* track= */ 0)
+    };
+
+    SampleStream[] streams = new SampleStream[1];
+    mergingMediaPeriod.selectTracks(
+        selectionArray,
+        /* mayRetainStreamFlags= */ new boolean[2],
+        streams,
+        /* streamResetFlags= */ new boolean[2],
+        /* positionUs= */ 0);
+    mergingMediaPeriod.continueLoading(/* positionUs= */ 0);
+
+    FormatHolder formatHolder = new FormatHolder();
+    DecoderInputBuffer inputBuffer =
+        new DecoderInputBuffer(DecoderInputBuffer.BUFFER_REPLACEMENT_MODE_NORMAL);
+    streams[0].readData(formatHolder, inputBuffer, FLAG_REQUIRE_FORMAT);
+
+    assertThat(streams[0].readData(formatHolder, inputBuffer, /* readFlags= */ 0))
+        .isEqualTo(C.RESULT_BUFFER_READ);
+    assertThat(inputBuffer.timeUs).isEqualTo(456_000 - 3000);
+  }
+
   private MergingMediaPeriod prepareMergingPeriod(MergingPeriodDefinition... definitions)
       throws Exception {
     MediaPeriod[] mediaPeriods = new MediaPeriod[definitions.length];