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src/loader/level-details.ts

  1. import { Part } from './fragment';
  2. import type { Fragment } from './fragment';
  3. import type { AttrList } from '../utils/attr-list';
  4. import type { DateRange } from './date-range';
  5.  
  6. const DEFAULT_TARGET_DURATION = 10;
  7.  
  8. export class LevelDetails {
  9.   public PTSKnown: boolean = false;
  10.   public alignedSliding: boolean = false;
  11.   public averagetargetduration?: number;
  12.   public endCC: number = 0;
  13.   public endSN: number = 0;
  14.   public fragments: Fragment[];
  15.   public fragmentHint?: Fragment;
  16.   public partList: Part[] | null = null;
  17.   public dateRanges: Record<string, DateRange>;
  18.   public live: boolean = true;
  19.   public ageHeader: number = 0;
  20.   public advancedDateTime?: number;
  21.   public updated: boolean = true;
  22.   public advanced: boolean = true;
  23.   public availabilityDelay?: number; // Manifest reload synchronization
  24.   public misses: number = 0;
  25.   public needSidxRanges: boolean = false;
  26.   public startCC: number = 0;
  27.   public startSN: number = 0;
  28.   public startTimeOffset: number | null = null;
  29.   public targetduration: number = 0;
  30.   public totalduration: number = 0;
  31.   public type: string | null = null;
  32.   public url: string;
  33.   public m3u8: string = '';
  34.   public version: number | null = null;
  35.   public canBlockReload: boolean = false;
  36.   public canSkipUntil: number = 0;
  37.   public canSkipDateRanges: boolean = false;
  38.   public skippedSegments: number = 0;
  39.   public recentlyRemovedDateranges?: string[];
  40.   public partHoldBack: number = 0;
  41.   public holdBack: number = 0;
  42.   public partTarget: number = 0;
  43.   public preloadHint?: AttrList;
  44.   public renditionReports?: AttrList[];
  45.   public tuneInGoal: number = 0;
  46.   public deltaUpdateFailed?: boolean;
  47.   public driftStartTime: number = 0;
  48.   public driftEndTime: number = 0;
  49.   public driftStart: number = 0;
  50.   public driftEnd: number = 0;
  51.  
  52.   constructor(baseUrl) {
  53.     this.fragments = [];
  54.     this.dateRanges = {};
  55.     this.url = baseUrl;
  56.   }
  57.  
  58.   reloaded(previous: LevelDetails | undefined) {
  59.     if (!previous) {
  60.       this.advanced = true;
  61.       this.updated = true;
  62.       return;
  63.     }
  64.     const partSnDiff = this.lastPartSn - previous.lastPartSn;
  65.     const partIndexDiff = this.lastPartIndex - previous.lastPartIndex;
  66.     this.updated =
  67.       this.endSN !== previous.endSN || !!partIndexDiff || !!partSnDiff;
  68.     this.advanced =
  69.       this.endSN > previous.endSN ||
  70.       partSnDiff > 0 ||
  71.       (partSnDiff === 0 && partIndexDiff > 0);
  72.     if (this.updated || this.advanced) {
  73.       this.misses = Math.floor(previous.misses * 0.6);
  74.     } else {
  75.       this.misses = previous.misses + 1;
  76.     }
  77.     this.availabilityDelay = previous.availabilityDelay;
  78.   }
  79.  
  80.   get hasProgramDateTime(): boolean {
  81.     if (this.fragments.length) {
  82.       return Number.isFinite(
  83.         this.fragments[this.fragments.length - 1].programDateTime as number
  84.       );
  85.     }
  86.     return false;
  87.   }
  88.  
  89.   get levelTargetDuration(): number {
  90.     return (
  91.       this.averagetargetduration ||
  92.       this.targetduration ||
  93.       DEFAULT_TARGET_DURATION
  94.     );
  95.   }
  96.  
  97.   get drift(): number {
  98.     const runTime = this.driftEndTime - this.driftStartTime;
  99.     if (runTime > 0) {
  100.       const runDuration = this.driftEnd - this.driftStart;
  101.       return (runDuration * 1000) / runTime;
  102.     }
  103.     return 1;
  104.   }
  105.  
  106.   get edge(): number {
  107.     return this.partEnd || this.fragmentEnd;
  108.   }
  109.  
  110.   get partEnd(): number {
  111.     if (this.partList?.length) {
  112.       return this.partList[this.partList.length - 1].end;
  113.     }
  114.     return this.fragmentEnd;
  115.   }
  116.  
  117.   get fragmentEnd(): number {
  118.     if (this.fragments?.length) {
  119.       return this.fragments[this.fragments.length - 1].end;
  120.     }
  121.     return 0;
  122.   }
  123.  
  124.   get age(): number {
  125.     if (this.advancedDateTime) {
  126.       return Math.max(Date.now() - this.advancedDateTime, 0) / 1000;
  127.     }
  128.     return 0;
  129.   }
  130.  
  131.   get lastPartIndex(): number {
  132.     if (this.partList?.length) {
  133.       return this.partList[this.partList.length - 1].index;
  134.     }
  135.     return -1;
  136.   }
  137.  
  138.   get lastPartSn(): number {
  139.     if (this.partList?.length) {
  140.       return this.partList[this.partList.length - 1].fragment.sn as number;
  141.     }
  142.     return this.endSN;
  143.   }
  144. }