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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 startCC: number = 0;
  26.   public startSN: number = 0;
  27.   public startTimeOffset: number | null = null;
  28.   public targetduration: number = 0;
  29.   public totalduration: number = 0;
  30.   public type: string | null = null;
  31.   public url: string;
  32.   public m3u8: string = '';
  33.   public version: number | null = null;
  34.   public canBlockReload: boolean = false;
  35.   public canSkipUntil: number = 0;
  36.   public canSkipDateRanges: boolean = false;
  37.   public skippedSegments: number = 0;
  38.   public recentlyRemovedDateranges?: string[];
  39.   public partHoldBack: number = 0;
  40.   public holdBack: number = 0;
  41.   public partTarget: number = 0;
  42.   public preloadHint?: AttrList;
  43.   public renditionReports?: AttrList[];
  44.   public tuneInGoal: number = 0;
  45.   public deltaUpdateFailed?: boolean;
  46.   public driftStartTime: number = 0;
  47.   public driftEndTime: number = 0;
  48.   public driftStart: number = 0;
  49.   public driftEnd: number = 0;
  50.   public encryptedFragments: Fragment[];
  51.  
  52.   constructor(baseUrl) {
  53.     this.fragments = [];
  54.     this.encryptedFragments = [];
  55.     this.dateRanges = {};
  56.     this.url = baseUrl;
  57.   }
  58.  
  59.   reloaded(previous: LevelDetails | undefined) {
  60.     if (!previous) {
  61.       this.advanced = true;
  62.       this.updated = true;
  63.       return;
  64.     }
  65.     const partSnDiff = this.lastPartSn - previous.lastPartSn;
  66.     const partIndexDiff = this.lastPartIndex - previous.lastPartIndex;
  67.     this.updated =
  68.       this.endSN !== previous.endSN || !!partIndexDiff || !!partSnDiff;
  69.     this.advanced =
  70.       this.endSN > previous.endSN ||
  71.       partSnDiff > 0 ||
  72.       (partSnDiff === 0 && partIndexDiff > 0);
  73.     if (this.updated || this.advanced) {
  74.       this.misses = Math.floor(previous.misses * 0.6);
  75.     } else {
  76.       this.misses = previous.misses + 1;
  77.     }
  78.     this.availabilityDelay = previous.availabilityDelay;
  79.   }
  80.  
  81.   get hasProgramDateTime(): boolean {
  82.     if (this.fragments.length) {
  83.       return Number.isFinite(
  84.         this.fragments[this.fragments.length - 1].programDateTime as number
  85.       );
  86.     }
  87.     return false;
  88.   }
  89.  
  90.   get levelTargetDuration(): number {
  91.     return (
  92.       this.averagetargetduration ||
  93.       this.targetduration ||
  94.       DEFAULT_TARGET_DURATION
  95.     );
  96.   }
  97.  
  98.   get drift(): number {
  99.     const runTime = this.driftEndTime - this.driftStartTime;
  100.     if (runTime > 0) {
  101.       const runDuration = this.driftEnd - this.driftStart;
  102.       return (runDuration * 1000) / runTime;
  103.     }
  104.     return 1;
  105.   }
  106.  
  107.   get edge(): number {
  108.     return this.partEnd || this.fragmentEnd;
  109.   }
  110.  
  111.   get partEnd(): number {
  112.     if (this.partList?.length) {
  113.       return this.partList[this.partList.length - 1].end;
  114.     }
  115.     return this.fragmentEnd;
  116.   }
  117.  
  118.   get fragmentEnd(): number {
  119.     if (this.fragments?.length) {
  120.       return this.fragments[this.fragments.length - 1].end;
  121.     }
  122.     return 0;
  123.   }
  124.  
  125.   get age(): number {
  126.     if (this.advancedDateTime) {
  127.       return Math.max(Date.now() - this.advancedDateTime, 0) / 1000;
  128.     }
  129.     return 0;
  130.   }
  131.  
  132.   get lastPartIndex(): number {
  133.     if (this.partList?.length) {
  134.       return this.partList[this.partList.length - 1].index;
  135.     }
  136.     return -1;
  137.   }
  138.  
  139.   get lastPartSn(): number {
  140.     if (this.partList?.length) {
  141.       return this.partList[this.partList.length - 1].fragment.sn as number;
  142.     }
  143.     return this.endSN;
  144.   }
  145. }