Merge branch 'patch/v1.5.x'

* patch/v1.5.x:
  Don't append over first fragment when next fragment aligns with playlist within 1/200s tolerance (#6471)
  Fix exception reading metadata.channelCount with HE-AAC when changeType is not supported (#6472)
  Fix TSDemuxer parsing error handling in sync path (#6469)
  when `this.stats` is called, add optional chaining or check for existence (#6459)

src/controller/base-stream-controller.ts

@@ -438,7 +438,7 @@ export default class BaseStreamController
         if (this.state === State.STOPPED || this.state === State.ERROR) {
           return;
         }
-        this.warn(reason);
+        this.warn(`Frag error: ${reason?.message || reason}`);
         this.resetFragmentLoading(frag);
       });
   }
@@ -1398,7 +1398,7 @@ export default class BaseStreamController
     let { fragPrevious } = this;
     let { fragments, endSN } = levelDetails;
     const { fragmentHint } = levelDetails;
-    const tolerance = config.maxFragLookUpTolerance;
+    const { maxFragLookUpTolerance } = config;
     const partList = levelDetails.partList;
 
     const loadingParts = !!(
@@ -1414,7 +1414,8 @@ export default class BaseStreamController
 
     let frag;
     if (bufferEnd < end) {
-      const lookupTolerance = bufferEnd > end - tolerance ? 0 : tolerance;
+      const lookupTolerance =
+        bufferEnd > end - maxFragLookUpTolerance ? 0 : maxFragLookUpTolerance;
       // Remove the tolerance if it would put the bufferEnd past the actual end of stream
       // Uses buffer and sequence number to calculate switch segment (required if using EXT-X-DISCONTINUITY-SEQUENCE)
       frag = findFragmentByPTS(

src/controller/fragment-finders.ts

@@ -58,6 +58,7 @@ export function findFragmentByPTS(
   fragments: Array<Fragment>,
   bufferEnd: number = 0,
   maxFragLookUpTolerance: number = 0,
+  nextFragLookupTolerance: number = 0.005,
 ): Fragment | null {
   let fragNext: Fragment | null = null;
   if (fragPrevious) {
@@ -76,9 +77,17 @@ export function findFragmentByPTS(
   // Prefer the next fragment if it's within tolerance
   if (
     fragNext &&
-    (!fragPrevious || fragPrevious.level === fragNext.level) &&
-    fragmentWithinToleranceTest(bufferEnd, maxFragLookUpTolerance, fragNext) ===
-      0
+    (((!fragPrevious || fragPrevious.level === fragNext.level) &&
+      fragmentWithinToleranceTest(
+        bufferEnd,
+        maxFragLookUpTolerance,
+        fragNext,
+      ) === 0) ||
+      fragmentWithinFastStartSwitch(
+        fragNext,
+        fragPrevious,
+        Math.min(nextFragLookupTolerance, maxFragLookUpTolerance),
+      ))
   ) {
     return fragNext;
   }
@@ -94,6 +103,28 @@ export function findFragmentByPTS(
   return fragNext;
 }
 
+function fragmentWithinFastStartSwitch(
+  fragNext: Fragment,
+  fragPrevious: Fragment | null,
+  nextFragLookupTolerance: number,
+): boolean {
+  if (
+    fragPrevious &&
+    fragPrevious.start === 0 &&
+    fragPrevious.level < fragNext.level &&
+    (fragPrevious.endPTS || 0) > 0
+  ) {
+    const firstDuration = fragPrevious.tagList.reduce((duration, tag) => {
+      if (tag[0] === 'INF') {
+        duration += parseFloat(tag[1]);
+      }
+      return duration;
+    }, nextFragLookupTolerance);
+    return fragNext.start <= firstDuration;
+  }
+  return false;
+}
+
 /**
  * The test function used by the findFragmentBySn's BinarySearch to look for the best match to the current buffer conditions.
  * @param candidate - The fragment to test

src/controller/stream-controller.ts

@@ -1268,7 +1268,13 @@ export default class StreamController
         // In the case that AAC and HE-AAC audio codecs are signalled in manifest,
         // force HE-AAC, as it seems that most browsers prefers it.
         // don't force HE-AAC if mono stream, or in Firefox
-        if (audio.metadata.channelCount !== 1 && ua.indexOf('firefox') === -1) {
+        const audioMetadata = audio.metadata;
+        if (
+          audioMetadata &&
+          'channelCount' in audioMetadata &&
+          (audioMetadata.channelCount || 1) !== 1 &&
+          ua.indexOf('firefox') === -1
+        ) {
           audioCodec = 'mp4a.40.5';
         }
       }

src/demux/transmuxer-interface.ts

@@ -17,7 +17,7 @@ import { Fragment, Part } from '../loader/fragment';
 import { getM2TSSupportedAudioTypes } from '../utils/codecs';
 import type { ChunkMetadata, TransmuxerResult } from '../types/transmuxer';
 import type Hls from '../hls';
-import type { HlsEventEmitter } from '../events';
+import type { HlsEventEmitter, HlsListeners } from '../events';
 import type { PlaylistLevelType } from '../types/loader';
 import type { RationalTimestamp } from '../utils/timescale-conversion';
 
@@ -30,7 +30,9 @@ export default class TransmuxerInterface {
   private part: Part | null = null;
   private useWorker: boolean;
   private workerContext: WorkerContext | null = null;
-  private onwmsg?: Function;
+  private onwmsg?: (
+    event: MessageEvent<{ event: string; data?: any } | null>,
+  ) => void;
   private transmuxer: Transmuxer | null = null;
   private onTransmuxComplete: (transmuxResult: TransmuxerResult) => void;
   private onFlush: (chunkMeta: ChunkMetadata) => void;
@@ -67,9 +69,6 @@ export default class TransmuxerInterface {
       config.preferManagedMediaSource,
     );
 
-    // navigator.vendor is not always available in Web Worker
-    // refer to https://developer.mozilla.org/en-US/docs/Web/API/WorkerGlobalScope/navigator
-    const vendor = navigator.vendor;
     if (this.useWorker && typeof Worker !== 'undefined') {
       const canCreateWorker = config.workerPath || hasUMDWorker();
       if (canCreateWorker) {
@@ -81,9 +80,9 @@ export default class TransmuxerInterface {
             logger.log(`injecting Web Worker for "${id}"`);
             this.workerContext = injectWorker();
           }
-          this.onwmsg = (ev: any) => this.onWorkerMessage(ev);
+          this.onwmsg = (event) => this.onWorkerMessage(event);
           const { worker } = this.workerContext;
-          worker.addEventListener('message', this.onwmsg as any);
+          worker.addEventListener('message', this.onwmsg);
           worker.onerror = (event) => {
             const error = new Error(
               `${event.message}  (${event.filename}:${event.lineno})`,
@@ -101,7 +100,7 @@ export default class TransmuxerInterface {
           worker.postMessage({
             cmd: 'init',
             typeSupported: m2tsTypeSupported,
-            vendor: vendor,
+            vendor: '',
             id: id,
             config: JSON.stringify(config),
           });
@@ -116,7 +115,7 @@ export default class TransmuxerInterface {
             this.observer,
             m2tsTypeSupported,
             config,
-            vendor,
+            '',
             id,
           );
         }
@@ -128,12 +127,12 @@ export default class TransmuxerInterface {
       this.observer,
       m2tsTypeSupported,
       config,
-      vendor,
+      '',
       id,
     );
   }
 
-  resetWorker(): void {
+  resetWorker() {
     if (this.workerContext) {
       const { worker, objectURL } = this.workerContext;
       if (objectURL) {
@@ -147,7 +146,7 @@ export default class TransmuxerInterface {
     }
   }
 
-  destroy(): void {
+  destroy() {
     if (this.workerContext) {
       this.resetWorker();
       this.onwmsg = undefined;
@@ -180,7 +179,7 @@ export default class TransmuxerInterface {
     accurateTimeOffset: boolean,
     chunkMeta: ChunkMetadata,
     defaultInitPTS?: RationalTimestamp,
-  ): void {
+  ) {
     chunkMeta.transmuxing.start = self.performance.now();
     const { transmuxer } = this;
     const timeOffset = part ? part.start : frag.start;
@@ -347,9 +346,20 @@ export default class TransmuxerInterface {
     this.onFlush(chunkMeta);
   }
 
-  private onWorkerMessage(ev: any): void {
-    const data = ev.data;
+  private onWorkerMessage(
+    event: MessageEvent<{ event: string; data?: any } | null>,
+  ) {
+    const data = event.data;
+    if (!data?.event) {
+      logger.warn(
+        `worker message received with no ${data ? 'event name' : 'data'}`,
+      );
+      return;
+    }
     const hls = this.hls;
+    if (!this.hls) {
+      return;
+    }
     switch (data.event) {
       case 'init': {
         const objectURL = this.workerContext?.objectURL;
@@ -381,7 +391,7 @@ export default class TransmuxerInterface {
         data.data = data.data || {};
         data.data.frag = this.frag;
         data.data.id = this.id;
-        hls.trigger(data.event, data.data);
+        hls.trigger(data.event as keyof HlsListeners, data.data);
         break;
       }
     }

src/demux/transmuxer-worker.ts

@@ -43,7 +43,7 @@ function startWorker(self) {
           observer,
           data.typeSupported,
           config,
-          data.vendor,
+          '',
           data.id,
         );
         const logger = enableLogs(config.debug, data.id);

src/demux/tsdemuxer.ts

@@ -374,6 +374,7 @@ class TSDemuxer implements Demuxer {
               offset,
               this.typeSupported,
               isSampleAes,
+              this.observer,
             );
 
             // only update track id if track PID found while parsing PMT
@@ -422,16 +423,12 @@ class TSDemuxer implements Demuxer {
     }
 
     if (tsPacketErrors > 0) {
-      const error = new Error(
-        `Found ${tsPacketErrors} TS packet/s that do not start with 0x47`,
+      emitParsingError(
+        this.observer,
+        new Error(
+          `Found ${tsPacketErrors} TS packet/s that do not start with 0x47`,
+        ),
       );
-      this.observer.emit(Events.ERROR, Events.ERROR, {
-        type: ErrorTypes.MEDIA_ERROR,
-        details: ErrorDetails.FRAG_PARSING_ERROR,
-        fatal: false,
-        error,
-        reason: error.message,
-      });
     }
 
     videoTrack.pesData = videoData;
@@ -628,16 +625,7 @@ class TSDemuxer implements Demuxer {
       } else {
         reason = 'No ADTS header found in AAC PES';
       }
-      const error = new Error(reason);
-      logger.warn(`parsing error: ${reason}`);
-      this.observer.emit(Events.ERROR, Events.ERROR, {
-        type: ErrorTypes.MEDIA_ERROR,
-        details: ErrorDetails.FRAG_PARSING_ERROR,
-        fatal: false,
-        levelRetry: recoverable,
-        error,
-        reason,
-      });
+      emitParsingError(this.observer, new Error(reason), recoverable);
       if (!recoverable) {
         return;
       }
@@ -768,6 +756,7 @@ function parsePMT(
   offset: number,
   typeSupported: TypeSupported,
   isSampleAes: boolean,
+  observer: HlsEventEmitter,
 ) {
   const result = {
     audioPid: -1,
@@ -897,7 +886,8 @@ function parsePMT(
       case 0xc2: // SAMPLE-AES EC3
       /* falls through */
       case 0x87:
-        throw new Error('Unsupported EC-3 in M2TS found');
+        emitParsingError(observer, new Error('Unsupported EC-3 in M2TS found'));
+        return result;
 
       case 0x24: // ITU-T Rec. H.265 and ISO/IEC 23008-2 (HEVC)
         if (__USE_M2TS_ADVANCED_CODECS__) {
@@ -907,7 +897,11 @@ function parsePMT(
             logger.log('HEVC in M2TS found');
           }
         } else {
-          throw new Error('Unsupported HEVC in M2TS found');
+          emitParsingError(
+            observer,
+            new Error('Unsupported HEVC in M2TS found'),
+          );
+          return result;
         }
         break;
 
@@ -922,6 +916,22 @@ function parsePMT(
   return result;
 }
 
+function emitParsingError(
+  observer: HlsEventEmitter,
+  error: Error,
+  levelRetry?: boolean,
+) {
+  logger.warn(`parsing error: ${error.message}`);
+  observer.emit(Events.ERROR, Events.ERROR, {
+    type: ErrorTypes.MEDIA_ERROR,
+    details: ErrorDetails.FRAG_PARSING_ERROR,
+    fatal: false,
+    levelRetry,
+    error,
+    reason: error.message,
+  });
+}
+
 function logEncryptedSamplesFoundInUnencryptedStream(type: string) {
   logger.log(`${type} with AES-128-CBC encryption found in unencrypted stream`);
 }