HTTPAdaptiveSource — HTTP/2 Adaptive Streaming Source

Documentation Index

Fetch the complete documentation index at: https://mintlify.com/CeeblueTV/wrts-client/llms.txt

Use this file to discover all available pages before exploring further.

​

Import

import { HTTPAdaptiveSource } from '@ceeblue/wrts-client';

​

Registration

// HTTPAdaptiveSource is used automatically
const player = new Player(videoElement);
player.start({ endPoint: 'https://example.com/wrts/out+<id>/index.json' });

​

Constructor

constructor(playing: IPlaying, params: Connect.Params)

​

How It Works

​

Manifest Fetch

• Sequence pattern (sequence.pattern) — a URL template used to construct per-sequence download URLs, e.g. {trackIds}/{sequenceId}.rts.
• Track separator (sequence.trackSeparator) — character used to join multiple track IDs in a combined URL (default: -).
• Current sequence ID and time (sequence.current.id, sequence.current.time) — used to compute how many sequences to pre-load into the buffer before live playback begins.
• Live time (metadata.liveTime) — corrected immediately using half the measured RTT of the manifest request.

​

Download Channel Model

• When reliable=true — all audio and video tracks go to the reliable channel.
• When reliable=false and the video track has a lower rendition available — video goes to skippable.
• When reliable=false and the video is already at the lowest rendition — video goes to alterable.

​

Adaptive Bitrate Algorithm

• Downgrade: triggered when a stall occurs (playing.onStall), when the alterable controller is aborted, or when BufferState.LOW is reached without a bandwidth measurement. The source walks the videoTrack.down chain until bandwidth consumption fits within the measured rate, then calls adaptiveRetry.raise() to back off UP attempts.
• Upgrade (UP emulation): when adaptiveRetry.try() returns true, a speculative GET request is fired in parallel against the next higher rendition (videoTrack.up) using _upController. If the download completes without being aborted, the track switches UP on the next iteration. If it is aborted (e.g. by a stall), adaptiveRetry.raise() is called and the delay before the next UP attempt increases.
• Screen resolution cap: after any rendition decision, the source also walks videoTrack.down while Media.overScreenSize(videoTrack.resolution, playing.maximumResolution) is true — ensuring the selected rendition never exceeds the display’s physical resolution.

​

Sequence Skipping

​

Key-Frame-Only Download (Alterable Channel)

​

CMCD Support

import { Player, HTTPAdaptiveSource, CMCD, CMCDMode } from '@ceeblue/wrts-client';

const player = new Player(videoElement, HTTPAdaptiveSource);
player.cmcd = CMCD.FULL;
player.cmcdMode = CMCDMode.QUERY;
player.cmcdSid = 'session-abc-123';
player.start({ endPoint: 'https://example.com/wrts/out+<id>/index.json' });

​

Track Selection

​

Inherited Properties

​

Usage Example

import { Player, HTTPAdaptiveSource } from '@ceeblue/wrts-client';

// Explicit class — identical to the default when using an https:// endpoint
const player = new Player(videoElement, HTTPAdaptiveSource);

player.onMetadata = (metadata) => {
  console.log('Available video tracks:', metadata.videoTracks);
  // Optionally return initial track selection
  return { video: metadata.videoTracks[0].id };
};

player.start({ endPoint: 'https://example.com/wrts/out+<id>/index.json' });

import { Player, HTTPAdaptiveSource, CMCD } from '@ceeblue/wrts-client';

const player = new Player(videoElement, HTTPAdaptiveSource);
player.cmcd = CMCD.FULL;
player.start({ endPoint: 'https://example.com/wrts/out+<id>/index.json' });

import { Player, HTTPAdaptiveSource } from '@ceeblue/wrts-client';

const player = new Player(videoElement, HTTPAdaptiveSource);
// Disable combined requests — audio and video fetched separately
player.tracksCombinable = false;
player.start({ endPoint: 'https://example.com/wrts/out+<id>/index.json' });

import { Player, HTTPAdaptiveSource } from '@ceeblue/wrts-client';

const player = new Player(videoElement, HTTPAdaptiveSource);
player.reliable = true; // No frame skipping; all sequences delivered in order
player.start({ endPoint: 'https://example.com/wrts/out+<id>/index.json' });