Add jassub/libpgs support on the web

src/index.ts

@@ -1,3 +1,4 @@
 export { useEvent, usePlayerState } from "./events";
 export { OmniProvider, usePlayer } from "./provider";
+export type { SubtitleAssets } from "./types/subtitles";
 export { OmniView } from "./view";

src/player.web.tsx

@@ -1,6 +1,10 @@
 import type { MediaVideoRendition } from "@videojs/core";
 import type { VideoPlayerStore } from "@videojs/core/dom";
-import { selectAudioTrack, selectQuality } from "@videojs/react";
+import {
+	selectAudioTrack,
+	selectQuality,
+	selectTextTrack,
+} from "@videojs/react";
 import { stateMapper } from "./events.web";
 import type {
 	OmniPlayer,
@@ -8,7 +12,35 @@ import type {
 	Rendition,
 	Track,
 } from "./types/player";
-import type { Source } from "./types/source";
+import type { Source, Subtitle } from "./types/source";
+
+export type SubtitleFormat = "vtt" | "ass" | "pgs" | "native";
+
+export const getSubtitleFormat = (subtitle: {
+	mimeType?: string;
+	link: string;
+}): SubtitleFormat => {
+	const mime = subtitle.mimeType?.toLowerCase() ?? "";
+	const ext = subtitle.link.split(/[?#]/)[0]?.split(".").pop()?.toLowerCase();
+	if (
+		mime.includes("ass") ||
+		mime.includes("ssa") ||
+		ext === "ass" ||
+		ext === "ssa"
+	)
+		return "ass";
+	if (mime.includes("pgs") || ext === "sup") return "pgs";
+	if (mime.includes("vtt") || ext === "vtt") return "vtt";
+	return "native";
+};
+
+export const isCustomSubtitle = (subtitle: {
+	mimeType?: string;
+	link: string;
+}): boolean => {
+	const format = getSubtitleFormat(subtitle);
+	return format === "ass" || format === "pgs";
+};
 
 export class WebOmniPlayer implements OmniPlayer {
 	_store: VideoPlayerStore;
@@ -22,12 +54,25 @@ export class WebOmniPlayer implements OmniPlayer {
 	_source: Source | null = null;
 	private _showNotification = false;
 
+	// Selected ASS/PGS subtitle (drawn by the overlay); `null` when the active
+	// subtitle is native or off. Exposed as an external store so the view can
+	// react to selection changes.
+	private overlaySubtitle: Subtitle | null = null;
+	private overlayListeners = new Set<() => void>();
+
 	get source(): Source | null {
 		return this._source;
 	}
 
 	set source(source: Source | null) {
 		this._source = source;
+		// Drop the overlay subtitle if it is not part of the new source.
+		if (
+			this.overlaySubtitle &&
+			!source?.subtitles.some((s) => s.id === this.overlaySubtitle?.id)
+		) {
+			this.setOverlaySubtitle(null);
+		}
 		this.updateMediaSession();
 	}
 
@@ -156,27 +201,53 @@ export class WebOmniPlayer implements OmniPlayer {
 		tracks.selectAudioTrack(audio.id);
 	}
 
+	private get overlaySubtitles(): Subtitle[] {
+		return (this._source?.subtitles ?? []).filter(isCustomSubtitle);
+	}
+
 	get subtitles(): Track[] {
-		return this._store.textTrackList
-			.map((x, i) => ({
-				id: i.toString(),
-				kind: x.kind,
-				label: x.label,
-				language: x.language,
-				selected: x.mode === "showing",
-			}))
-			.filter((x) => x.kind === "subtitles" || x.kind === "captions");
+		const textTracks = selectTextTrack(this._store.state)?.textTrackList ?? [];
+		const native = textTracks
+			.filter((x) => x.kind === "subtitles" || x.kind === "captions")
+			.map((track) => ({
+				id: track.id!,
+				label: track.label,
+				language: track.language,
+				selected: track.mode === "showing",
+			}));
+		const overlay = this.overlaySubtitles.map((sub) => ({
+			id: sub.id,
+			label: sub.label,
+			language: sub.language,
+			selected: this.overlaySubtitle?.id === sub.id,
+		}));
+		return [...native, ...overlay];
 	}
 
 	selectSubtitle(subtitle?: Track): void {
-		for (let i = 0; i < this._store.textTrackList.length; i++) {
-			const track = this._store.textTrackList[i]!;
-			if (track.kind !== "subtitles" && track.kind !== "captions") continue;
-			track.mode =
-				subtitle && i.toString() === subtitle.id ? "showing" : "hidden";
-		}
+		const overlay = subtitle
+			? this.overlaySubtitles.find((s) => s.id === subtitle.id)
+			: undefined;
+
+		const tracks = selectTextTrack(this._store.state);
+		tracks?.selectSubtitlesTrack(overlay || !subtitle ? "off" : subtitle.id);
+		this.setOverlaySubtitle(overlay ?? null);
 	}
 
+	private setOverlaySubtitle(sub: Subtitle | null): void {
+		if (this.overlaySubtitle === sub) return;
+		this.overlaySubtitle = sub;
+		for (const listener of this.overlayListeners) listener();
+	}
+
+	// External store used by the view to render the ASS/PGS overlay.
+	subscribeOverlaySubtitle = (callback: () => void): (() => void) => {
+		this.overlayListeners.add(callback);
+		return () => this.overlayListeners.delete(callback);
+	};
+
+	getOverlaySubtitle = (): Subtitle | null => this.overlaySubtitle;
+
 	get rendition(): Rendition[] {
 		function isSameRendition(
 			a: MediaVideoRendition,

src/types/source.ts

@@ -2,6 +2,9 @@ export interface Source {
 	src: VideoSrc[];
 	startTime?: number;
 	subtitles: Subtitle[];
+	// fonts that can be used by ass subtitles on the web (native will use
+	// embedded fonts)
+	fonts?: string[];
 	metadata?: Metadata;
 	mixAudio?: MixAudioMode;
 }

src/types/subtitles.ts

@@ -0,0 +1,16 @@
+export interface SubtitleAssets {
+	jassub?: {
+		/** URL of `jassub-worker.js`. */
+		workerUrl?: string;
+		/** URL of `jassub-worker.wasm`. */
+		wasmUrl?: string;
+		/** URL of `jassub-worker-modern.wasm`. */
+		modernWasmUrl?: string;
+		/** URL of a fallback font used when the ASS file references none. */
+		fontUrl?: string;
+	};
+	pgs?: {
+		/** URL of `libpgs.worker.js`. */
+		workerUrl?: string;
+	};
+}

src/types/view.ts

@@ -1,4 +1,8 @@
+import type { SubtitleAssets } from "./subtitles";
+
 export interface OmniViewProps {
 	autoplay?: boolean;
 	autoPip?: boolean;
+	/** Web-only: URLs for the ASS/PGS subtitle renderer assets. */
+	subtitleAssets?: SubtitleAssets;
 }

src/utils/lazy-ref.ts

@@ -2,5 +2,5 @@ import { useState } from "react";
 
 export const useLazyRef = <T>(init: () => T): T => {
 	const [ret] = useState<T>(init);
-	return ret
+	return ret;
 };

src/view.tsx

@@ -1,3 +1,5 @@
+import { memo } from "react";
+import type { ViewStyle } from "react-native";
 import {
 	getHostComponent,
 	type HybridViewMethods,
@@ -7,14 +9,18 @@ import { usePlayer } from "./provider";
 import type { OmniPlayer } from "./specs/omni-player.nitro";
 import type { Props } from "./specs/omni-view.nitro";
 import type { OmniViewProps } from "./types/view";
-import type { ViewStyle } from "react-native";
-import { memo } from "react";
 
 const NativeView = memo(
 	getHostComponent<Props, HybridViewMethods>("OmniView", () => OmniConfig),
 );
 
-export const OmniView = memo((props: OmniViewProps & { style: ViewStyle }) => {
-	const player = usePlayer() as OmniPlayer;
-	return <NativeView player={player} {...props} />;
-});
+export const OmniView = memo(
+	({
+		// Web-only; not forwarded to the native view.
+		subtitleAssets: _subtitleAssets,
+		...props
+	}: OmniViewProps & { style: ViewStyle }) => {
+		const player = usePlayer() as OmniPlayer;
+		return <NativeView player={player} {...props} />;
+	},
+);

src/view.web.tsx

@@ -1,33 +1,100 @@
 import type { HlsMediaConfig } from "@videojs/core/dom/media/hls-js";
 import { HlsJsVideo } from "@videojs/react/media/hlsjs-video";
 import { Video } from "@videojs/react/video";
-import { type CSSProperties, useMemo, useRef } from "react";
-import type { WebOmniPlayer } from "./player.web";
-import { usePlayer } from "./provider";
-import { VideoPlayer } from "./provider.web";
-import type { Subtitle } from "./types/source";
+import {
+	type CSSProperties,
+	type RefObject,
+	useEffect,
+	useMemo,
+	useRef,
+	useSyncExternalStore,
+} from "react";
+import {
+	getSubtitleFormat,
+	isCustomSubtitle,
+	type WebOmniPlayer,
+} from "./player.web";
+import { usePlayer, VideoPlayer } from "./provider.web";
+import type { SubtitleAssets } from "./types/subtitles";
 import type { OmniViewProps } from "./types/view";
 
-const SubtitleTracks = ({ subtitles }: { subtitles: Subtitle[] }) => (
-	<>
-		{subtitles.map((subtitle) => (
-			<track
-				key={subtitle.id}
-				kind="subtitles"
-				src={subtitle.link}
-				srcLang={subtitle.language}
-				label={subtitle.label ?? subtitle.language ?? subtitle.id}
-			/>
-		))}
-	</>
-);
+const SubtitleOverlay = ({
+	video,
+	assets,
+	fonts,
+}: {
+	video: RefObject<HTMLVideoElement>;
+	assets?: SubtitleAssets;
+	fonts?: string[];
+}) => {
+	const player = usePlayer() as WebOmniPlayer;
+	const subtitle = useSyncExternalStore(
+		player.subscribeOverlaySubtitle,
+		player.getOverlaySubtitle,
+		() => null,
+	);
+	const assetsRef = useRef(assets);
+	assetsRef.current = assets;
+	const fontsRef = useRef(fonts);
+	fontsRef.current = fonts;
+
+	useEffect(() => {
+		const el = video.current;
+		if (!el || !subtitle) return;
+		let renderer: { destroy(): void } | null = null;
+		let cancelled = false;
+		const attach = (created: { destroy(): void }) => {
+			if (cancelled) created.destroy();
+			else renderer = created;
+		};
+
+		if (getSubtitleFormat(subtitle) === "ass") {
+			const jassub = assetsRef.current?.jassub;
+			const fonts = fontsRef.current;
+			import("jassub").then(({ default: JASSUB }) => {
+				const instance = new JASSUB({
+					video: el,
+					subUrl: subtitle.link,
+					...(fonts?.length && { fonts }),
+					...(jassub?.workerUrl && { workerUrl: jassub.workerUrl }),
+					...(jassub?.wasmUrl && { wasmUrl: jassub.wasmUrl }),
+					...(jassub?.modernWasmUrl && { modernWasmUrl: jassub.modernWasmUrl }),
+					...(jassub?.fontUrl && {
+						availableFonts: { "liberation sans": jassub.fontUrl },
+						defaultFont: "liberation sans",
+					}),
+				});
+				attach({ destroy: () => instance.destroy() });
+			});
+		} else {
+			const pgs = assetsRef.current?.pgs;
+			import("libpgs").then(({ PgsRenderer }) => {
+				const instance = new PgsRenderer({
+					video: el,
+					subUrl: subtitle.link,
+					...(pgs?.workerUrl && { workerUrl: pgs.workerUrl }),
+				});
+				attach({ destroy: () => instance.dispose() });
+			});
+		}
+
+		return () => {
+			cancelled = true;
+			renderer?.destroy();
+		};
+	}, [video, subtitle]);
+
+	return null;
+};
 
 export const OmniView = ({
 	style,
 	autoplay,
+	subtitleAssets,
 }: OmniViewProps & { style: CSSProperties }) => {
 	const player = usePlayer() as WebOmniPlayer;
 	const containerRef = useRef<HTMLDivElement>(null);
+	const ref = useRef<HTMLVideoElement>(undefined!);
 
 	const src = player.source?.src[0];
 	const Tech = src?.uri.endsWith("m3u8") ? HlsJsVideo : Video;
@@ -47,23 +114,38 @@ export const OmniView = ({
 	}, [src?.headers]);
 
 	return (
-		<VideoPlayer.Container ref={containerRef} style={style}>
+		<VideoPlayer.Container
+			ref={containerRef}
+			style={{ position: "relative", ...style }}
+		>
 			{src && (
 				<Tech
+					ref={ref}
 					src={src.uri}
 					config={config}
 					autoPlay={autoplay}
 					playsInline
 					crossOrigin="anonymous"
-					style={{
-						width: "100%",
-						height: "100%",
-						objectFit: "contain",
-					}}
+					style={{ width: "100%", height: "100%", objectFit: "contain" }}
 				>
-					<SubtitleTracks subtitles={player.source?.subtitles ?? []} />
+					{(player.source?.subtitles ?? [])
+						.filter((subtitle) => !isCustomSubtitle(subtitle))
+						.map((subtitle) => (
+							<track
+								key={subtitle.id}
+								kind="subtitles"
+								src={subtitle.link}
+								srcLang={subtitle.language}
+								label={subtitle.label ?? subtitle.language ?? subtitle.id}
+							/>
+						))}
 				</Tech>
 			)}
+			<SubtitleOverlay
+				video={ref}
+				assets={subtitleAssets}
+				fonts={player.source?.fonts}
+			/>
 		</VideoPlayer.Container>
 	);
 };