fix: Fix metadata timing when using TS (#7478)

Fixes #7473

Author: avelad

lib/media/media_source_engine.js

@@ -787,13 +787,12 @@ shaka.media.MediaSourceEngine = class {
    * @param {?shaka.media.SegmentReference} reference The segment reference
    *   we are appending, or null for init segments
    * @param {!string} mimeType
-   * @param {!number} timestampOffset
-   * @return {?number}
+   * @return {{timestamp: ?number, metadata: !Array.<shaka.extern.ID3Metadata>}}
    * @private
    */
-  getTimestampAndDispatchMetadata_(contentType, data, reference, mimeType,
-      timestampOffset) {
+  getTimestampAndDispatchMetadata_(contentType, data, reference, mimeType) {
     let timestamp = null;
+    let metadata = [];
 
     const uint8ArrayData = shaka.util.BufferUtils.toUint8(data);
     if (shaka.util.MimeUtils.RAW_FORMATS.includes(mimeType)) {
@@ -807,15 +806,15 @@ shaka.media.MediaSourceEngine = class {
           timestamp = Math.round(metadataTimestamp.data) / 1000;
         }
         /** @private {shaka.extern.ID3Metadata} */
-        const metadata = {
+        const id3Metadata = {
           cueTime: reference.startTime,
           data: uint8ArrayData,
           frames: frames,
           dts: reference.startTime,
           pts: reference.startTime,
         };
         this.playerInterface_.onMetadata(
-            [metadata], /* offset= */ 0, reference.endTime);
+            [id3Metadata], /* offset= */ 0, reference.endTime);
       }
     } else if (mimeType.includes('/mp4') &&
         reference && reference.timestampOffset == 0 &&
@@ -855,13 +854,9 @@ shaka.media.MediaSourceEngine = class {
       if (startTime != null) {
         timestamp = startTime;
       }
-      const metadata = tsParser.getMetadata();
-      if (metadata.length) {
-        this.playerInterface_.onMetadata(metadata, timestampOffset,
-            reference ? reference.endTime : null);
-      }
+      metadata = tsParser.getMetadata();
     }
-    return timestamp;
+    return {timestamp, metadata};
   }
 
   /**
@@ -925,8 +920,8 @@ shaka.media.MediaSourceEngine = class {
       mimeType = this.transmuxers_[contentType].getOriginalMimeType();
     }
     if (reference) {
-      const timestamp = this.getTimestampAndDispatchMetadata_(
-          contentType, data, reference, mimeType, timestampOffset);
+      const {timestamp, metadata} = this.getTimestampAndDispatchMetadata_(
+          contentType, data, reference, mimeType);
       if (timestamp != null) {
         if (this.firstVideoTimestamp_ == null &&
             contentType == ContentType.VIDEO) {
@@ -988,6 +983,10 @@ shaka.media.MediaSourceEngine = class {
           this.textSequenceModeOffset_.resolve(timestampOffset);
         }
       }
+      if (metadata.length) {
+        this.playerInterface_.onMetadata(metadata, timestampOffset,
+            reference ? reference.endTime : null);
+      }
     }
     if (hasClosedCaptions && contentType == ContentType.VIDEO) {
       if (!this.textEngine_) {