Determine canSkip based on age of last playlist request

src/controller/audio-track-controller.ts

@@ -401,7 +401,7 @@ class AudioTrackController extends BasePlaylistController {
   protected loadPlaylist(hlsUrlParameters?: HlsUrlParameters): void {
     const audioTrack = this.currentTrack;
     if (this.shouldLoadPlaylist(audioTrack) && audioTrack) {
-      super.loadPlaylist();
+      super.loadPlaylist(hlsUrlParameters, audioTrack.details);
       const id = audioTrack.id;
       const groupId = audioTrack.groupId as string;
       let url = audioTrack.url;

src/controller/base-playlist-controller.ts

@@ -1,6 +1,6 @@
 import type Hls from '../hls';
 import type { NetworkComponentAPI } from '../types/component-api';
-import { getSkipValue, HlsSkip, HlsUrlParameters, Level } from '../types/level';
+import { HlsSkip, HlsUrlParameters, Level, getSkipValue } from '../types/level';
 import { computeReloadInterval, mergeDetails } from '../utils/level-helper';
 import { ErrorData } from '../types/events';
 import { getRetryDelay, isTimeoutError } from '../utils/error-helper';
@@ -101,7 +101,14 @@ export default class BasePlaylistController
     }
   }
 
-  protected loadPlaylist(hlsUrlParameters?: HlsUrlParameters): void {
+  protected loadPlaylist(
+    hlsUrlParameters?: HlsUrlParameters,
+    levelDetails?: LevelDetails,
+  ): void {
+    const skipValue = levelDetails && getSkipValue(levelDetails);
+    if (hlsUrlParameters) {
+      hlsUrlParameters.skip = skipValue;
+    }
     if (this.requestScheduled === -1) {
       this.requestScheduled = self.performance.now();
     }
@@ -310,7 +317,7 @@ export default class BasePlaylistController
     msn?: number,
     part?: number,
   ): HlsUrlParameters {
-    let skip = getSkipValue(details, msn);
+    let skip: HlsSkip | undefined;
     if (previousDeliveryDirectives?.skip && details.deltaUpdateFailed) {
       msn = previousDeliveryDirectives.msn;
       part = previousDeliveryDirectives.part;

src/controller/level-controller.ts

@@ -570,9 +570,9 @@ export default class LevelController extends BasePlaylistController {
   }
 
   protected loadPlaylist(hlsUrlParameters?: HlsUrlParameters) {
-    super.loadPlaylist();
     const currentLevelIndex = this.currentLevelIndex;
     const currentLevel = this.currentLevel;
+    super.loadPlaylist(hlsUrlParameters, currentLevel?.details);
 
     if (currentLevel && this.shouldLoadPlaylist(currentLevel)) {
       let url = currentLevel.uri;

src/controller/subtitle-track-controller.ts

@@ -421,8 +421,8 @@ class SubtitleTrackController extends BasePlaylistController {
   }
 
   protected loadPlaylist(hlsUrlParameters?: HlsUrlParameters): void {
-    super.loadPlaylist();
     const currentTrack = this.currentTrack;
+    super.loadPlaylist(hlsUrlParameters, currentTrack?.details);
     if (this.shouldLoadPlaylist(currentTrack) && currentTrack) {
       const id = currentTrack.id;
       const groupId = currentTrack.groupId as string;

src/types/level.ts

@@ -59,10 +59,13 @@ export const enum HlsSkip {
   v2 = 'v2',
 }
 
-export function getSkipValue(details: LevelDetails, msn?: number): HlsSkip {
-  const { canSkipUntil, canSkipDateRanges, endSN } = details;
-  const snChangeGoal = msn !== undefined ? msn - endSN : 0;
-  if (canSkipUntil && snChangeGoal < canSkipUntil) {
+export function getSkipValue(details: LevelDetails): HlsSkip {
+  const { canSkipUntil, canSkipDateRanges, age } = details;
+  // A Client SHOULD NOT request a Playlist Delta Update unless it already
+  // has a version of the Playlist that is no older than one-half of the Skip Boundary.
+  // @see: https://datatracker.ietf.org/doc/html/draft-pantos-hls-rfc8216bis#section-6.3.7
+  const playlistRecentEnough = age < canSkipUntil / 2;
+  if (canSkipUntil && playlistRecentEnough) {
     if (canSkipDateRanges) {
       return HlsSkip.v2;
     }