v10/dist/dev/dom/hls-js/live.js

import { MediaStreamTypes } from "../../core/types.js";
import Hls from "hls.js";
//#region src/dom/hls-js/live.ts
function HlsJsMediaLiveMixin(BaseClass) {
	class HlsJsMediaLive extends BaseClass {
		#targetLiveWindow = NaN;
		#liveEdgeStartOffset;
		#seekToLiveAbort = null;
		#seekToLivePending = false;
		constructor(...args) {
			super(...args);
			const { engine } = this;
			engine?.on(Hls.Events.MANIFEST_LOADING, () => {
				this.#reset();
				this.#armSeekToLive();
			});
			engine?.on(Hls.Events.MEDIA_ATTACHED, () => this.#armSeekToLive());
			engine?.on(Hls.Events.MEDIA_DETACHED, () => this.#disarmSeekToLive());
			engine?.on(Hls.Events.DESTROYING, () => {
				this.#reset();
				this.#disarmSeekToLive();
			});
			engine?.on(Hls.Events.LEVEL_LOADED, (_event, data) => {
				this.#derive(data.details);
				if (this.#seekToLivePending) this.#trySeekToLive();
			});
		}
		get targetLiveWindow() {
			return this.#targetLiveWindow;
		}
		get liveEdgeStart() {
			if (this.#liveEdgeStartOffset === void 0) return NaN;
			const { target } = this;
			if (!target) return NaN;
			const { seekable } = target;
			if (!seekable.length) return NaN;
			return seekable.end(seekable.length - 1) - this.#liveEdgeStartOffset;
		}
		#derive(details) {
			if (!details.live) return this.#reset();
			const info = getStreamInfoFromHlsjsLevelDetails(details);
			this.#liveEdgeStartOffset = info.liveEdgeStartOffset;
			this.#updateConfig(info);
			this.#setTargetLiveWindow(info.targetLiveWindow);
		}
		#reset() {
			this.#liveEdgeStartOffset = void 0;
			this.#setTargetLiveWindow(NaN);
		}
		#updateConfig({ streamType, lowLatency }) {
			if (streamType === MediaStreamTypes.LIVE) {
				const hls = this.engine;
				if (!hls) return;
				if (lowLatency) {
					hls.config.backBufferLength = hls.userConfig.backBufferLength ?? 4;
					hls.config.maxFragLookUpTolerance = hls.userConfig.maxFragLookUpTolerance ?? .001;
					hls.config.abrBandWidthUpFactor = hls.userConfig.abrBandWidthUpFactor ?? hls.config.abrBandWidthFactor;
				} else hls.config.backBufferLength = hls.userConfig.backBufferLength ?? 8;
			}
		}
		#setTargetLiveWindow(value) {
			if (Object.is(this.#targetLiveWindow, value)) return;
			this.#targetLiveWindow = value;
			this.dispatchEvent(new Event("targetlivewindowchange"));
		}
		/**
		* Arm a one-shot seek-to-live on the first user-initiated `play`. Skipped
		* when `autoplay` is set, since hls.js positions at the live edge during
		* its own startup sequence and a programmatic seek would race that.
		*/
		#armSeekToLive() {
			this.#disarmSeekToLive();
			const target = this.target;
			if (!target || target.autoplay) return;
			this.#seekToLiveAbort = new AbortController();
			target.addEventListener("play", () => {
				this.#seekToLivePending = true;
				this.#trySeekToLive();
			}, {
				signal: this.#seekToLiveAbort.signal,
				once: true
			});
		}
		#disarmSeekToLive() {
			this.#seekToLiveAbort?.abort();
			this.#seekToLiveAbort = null;
			this.#seekToLivePending = false;
		}
		#trySeekToLive() {
			const target = this.target;
			if (!target) return;
			const { liveEdgeStart } = this;
			if (!Number.isFinite(liveEdgeStart)) return;
			if (target.currentTime < liveEdgeStart) target.currentTime = liveEdgeStart;
			this.#seekToLivePending = false;
		}
	}
	return HlsJsMediaLive;
}
const getStreamInfoFromHlsjsLevelDetails = (levelDetails) => {
	const playlistType = levelDetails.type;
	const streamType = toStreamTypeFromPlaylistType(playlistType);
	const targetLiveWindow = toTargetLiveWindowFromPlaylistType(playlistType);
	const lowLatency = !!levelDetails.partList?.length;
	let liveEdgeStartOffset;
	if (streamType === MediaStreamTypes.LIVE) liveEdgeStartOffset = lowLatency ? levelDetails.partHoldBack || levelDetails.partTarget * 2 : levelDetails.holdBack || levelDetails.targetduration * 3;
	return {
		streamType,
		targetLiveWindow,
		liveEdgeStartOffset,
		lowLatency
	};
};
const toStreamTypeFromPlaylistType = (playlistType) => {
	return playlistType === "VOD" ? MediaStreamTypes.ON_DEMAND : MediaStreamTypes.LIVE;
};
const toTargetLiveWindowFromPlaylistType = (playlistType) => {
	if (playlistType === "EVENT") return Number.POSITIVE_INFINITY;
	if (playlistType === "VOD") return NaN;
	return 0;
};
//#endregion
export { HlsJsMediaLiveMixin };

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