diff --git a/lib/util/periods.js b/lib/util/periods.js
index 4a4fd1fc20..2472d1f1d9 100644
--- a/lib/util/periods.js
+++ b/lib/util/periods.js
@@ -573,7 +573,7 @@ shaka.util.PeriodCombiner = class {
 
     // We need to create all the per-period segment indexes and append them to
     // the output's MetaSegmentIndex.
-    await Promise.all(matches.map((match) => match.createSegmentIndex()));
+    await shaka.util.PeriodCombiner.createSegmentIndexes_(matches);
 
     // Assure the compiler that matches didn't become null during the async
     // operation above.
@@ -585,6 +585,25 @@ shaka.util.PeriodCombiner = class {
     return true;
   }
 
+  /**
+   * Creates all segment indexes for an array of streams.  Returns once every
+   * segment index is created.
+   *
+   * @param {!Array.<!shaka.extern.Stream>} streams
+   * @return {!Promise}
+   * @private
+   */
+  static createSegmentIndexes_(streams) {
+    const operations = [];
+    for (const stream of streams) {
+      operations.push(stream.createSegmentIndex());
+      if (stream.trickModeVideo && !stream.trickModeVideo.segmentIndex) {
+        operations.push(stream.trickModeVideo.createSegmentIndex());
+      }
+    }
+    return Promise.all(operations);
+  }
+
   /**
    * Create a new output Stream based on a particular input Stream.  Locates
    * matching Streams in all other periods and combines them into an output
@@ -627,7 +646,7 @@ shaka.util.PeriodCombiner = class {
     if (outputStream.createSegmentIndex) {
       // For T == Stream, we need to create all the per-period segment indexes
       // in advance.  concat() will add them to the output's MetaSegmentIndex.
-      await Promise.all(matches.map((match) => match.createSegmentIndex()));
+      await shaka.util.PeriodCombiner.createSegmentIndexes_(matches);
     }
 
     // Assure the compiler that matches didn't become null during the async