Handle Interstitials with empty asset-lists (skip to resumption offse…

…t or abutting interstitial)

src/controller/interstitials-controller.ts

@@ -1045,7 +1045,7 @@ MediaSource ${JSON.stringify(attachMediaSourceData)} from ${logFromSource}`,
         });
       }
       const assetListLength = interstitial.assetList.length;
-      if (assetListLength === 0) {
+      if (assetListLength === 0 && !interstitial.assetListResponse) {
         // Waiting at end of primary content segment
         // Expect setSchedulePosition to be called again once ASSET-LIST is loaded
         this.log(`Waiting for ASSET-LIST to complete loading ${interstitial}`);
@@ -1064,29 +1064,25 @@ MediaSource ${JSON.stringify(attachMediaSourceData)} from ${logFromSource}`,
       // Update schedule and asset list position now that it can start
       this.waitingItem = null;
       this.playingItem = scheduledItem;
-      // Start Interstitial Playback
+
+      // If asset-list is empty or missing asset index, advance to next item
       const assetItem = interstitial.assetList[assetListIndex];
       if (!assetItem) {
-        const error = new Error(
-          `ASSET-LIST index ${assetListIndex} out of bounds [0-${
-            assetListLength - 1
-          }] ${interstitial}`,
-        );
-        const errorData: ErrorData = {
-          fatal: true,
-          type: ErrorTypes.OTHER_ERROR,
-          details: ErrorDetails.INTERSTITIAL_ASSET_ITEM_ERROR,
-          error,
-        };
-        this.handleAssetItemError(
-          errorData,
-          interstitial,
-          index,
-          assetListIndex,
-          error.message,
-        );
+        const nextItem = scheduleItems[index + 1];
+        const media = this.media;
+        if (
+          nextItem &&
+          media &&
+          !this.isInterstitial(nextItem) &&
+          media.currentTime < nextItem.start
+        ) {
+          media.currentTime = this.timelinePos = nextItem.start;
+        }
+        this.advanceAfterAssetEnded(interstitial, index, assetListIndex || 0);
         return;
       }
+
+      // Start Interstitial Playback
       if (!player) {
         player = this.getAssetPlayer(assetItem.identifier);
       }
@@ -1411,7 +1407,7 @@ MediaSource ${JSON.stringify(attachMediaSourceData)} from ${logFromSource}`,
         interstitialEvents.forEach((event) => (event.appendInPlace = false));
       }
       this.log(
-        `Interstitial events (${
+        `INTERSTITIALS_UPDATED (${
           interstitialEvents.length
         }): ${interstitialEvents}
 Schedule: ${scheduleItems.map((seg) => segmentToString(seg))}`,

tests/unit/controller/interstitials-controller.ts

@@ -1157,5 +1157,82 @@ fileSequence5.mp4`;
       expect(insterstitials.bufferingIndex).to.equal(0, 'bufferingIndex');
       expect(insterstitials.playingIndex).to.equal(0, 'playingIndex');
     });
+
+    it('should handle empty asset-lists', function () {
+      const playlist = `#EXTM3U
+#EXT-X-TARGETDURATION:10
+#EXT-X-VERSION:7
+#EXT-X-MEDIA-SEQUENCE:1
+#EXT-X-PROGRAM-DATE-TIME:2024-02-23T15:00:00.000Z
+#EXT-X-DATERANGE:ID="start",CLASS="com.apple.hls.interstitial",START-DATE="2024-02-23T15:00:00.000Z",DURATION=5,X-ASSET-LIST="https://example.com/empty.m3u8",X-RESUME-OFFSET=5
+#EXT-X-MAP:URI="fileSequence0.mp4"
+#EXTINF:5,	
+fileSequence1.mp4
+#EXTINF:5,	
+fileSequence2.mp4
+#EXTINF:5,	
+fileSequence3.mp4
+#EXT-X-ENDLIST`;
+      const media = new MockMediaElement();
+      hls.attachMedia(media as unknown as HTMLMediaElement);
+      (hls as any).bufferController.media = media;
+      hls.trigger(Events.MEDIA_ATTACHED, {
+        media: media as unknown as HTMLMediaElement,
+        mediaSource: {} as any,
+      });
+
+      const details = setLoadedLevelDetails(playlist);
+      hls.trigger(Events.LEVEL_UPDATED, {
+        details,
+        level: 0,
+      });
+      const insterstitials = interstitialsController.interstitialsManager;
+      if (!insterstitials) {
+        expect(insterstitials, 'interstitialsManager').to.be.an('object');
+        return;
+      }
+      expect(insterstitials.events).is.an('array').which.has.lengthOf(1);
+      expect(insterstitials.schedule).is.an('array').which.has.lengthOf(2);
+      if (!insterstitials.events || !insterstitials.schedule) {
+        return;
+      }
+      const callsBeforeAttach = getTriggerCalls();
+      expect(callsBeforeAttach).to.deep.equal(
+        [
+          Events.MEDIA_ATTACHING,
+          Events.MEDIA_ATTACHED,
+          Events.LEVEL_UPDATED,
+          Events.INTERSTITIALS_UPDATED,
+          Events.ASSET_LIST_LOADING,
+          Events.INTERSTITIALS_BUFFERED_TO_BOUNDARY,
+          Events.INTERSTITIAL_STARTED,
+        ],
+        `Actual events before asset-list: ${callsBeforeAttach.join(', ')}`,
+      );
+      hls.trigger.resetHistory();
+      expect(insterstitials.bufferingIndex).to.equal(0, 'bufferingIndex');
+      expect(insterstitials.playingIndex).to.equal(0, 'playingIndex');
+
+      // Load empty asset-list
+      const interstitial = insterstitials.events[0];
+      interstitial.assetListResponse = { ASSETS: [] };
+      hls.trigger(Events.ASSET_LIST_LOADED, {
+        event: interstitial,
+        assetListResponse: interstitial.assetListResponse,
+        networkDetails: {},
+      });
+      const callsAfterAttach = getTriggerCalls();
+      expect(callsAfterAttach).to.deep.equal(
+        [
+          Events.ASSET_LIST_LOADED,
+          Events.INTERSTITIAL_ENDED,
+          Events.INTERSTITIALS_BUFFERED_TO_BOUNDARY,
+          Events.INTERSTITIALS_PRIMARY_RESUMED,
+        ],
+        `Actual events after asset-list: ${callsAfterAttach.join(', ')}`,
+      );
+      expect(insterstitials.bufferingIndex).to.equal(1, 'bufferingIndex');
+      expect(insterstitials.playingIndex).to.equal(1, 'playingIndex');
+    });
   });
 });