feat(core): Support AirPlay on MSE (#1692)

packages/core/src/dom/media/hls-js/airplay-bridge.ts

@@ -0,0 +1,87 @@
+import { isWebKitAirPlayCapable, listen, type WebKitVideoElement } from '@videojs/utils/dom';
+import type { Constructor } from '@videojs/utils/types';
+import Hls from 'hls.js';
+import type { HlsEngineHost } from './types';
+
+/**
+ * Adds an AirPlay-capable fallback `<source>` to the attached video element so
+ * Safari can hand the original HLS manifest off to AirPlay receivers while
+ * local playback continues through hls.js (MSE).
+ * When wireless-target changes, suspends hls.js loading so we don't double-fetch
+ * alongside the AirPlay receiver.
+ *
+ * Implements the WebKit-recommended pattern:
+ * https://webkit.org/blog/15036/how-to-use-media-source-extensions-with-airplay/
+ *
+ * No-op on non-WebKit platforms (Chromium, Firefox).
+ */
+export function HlsJsMediaAirPlayMixin<Base extends Constructor<HlsEngineHost>>(BaseClass: Base) {
+  class HlsJsMediaAirPlay extends (BaseClass as Constructor<HlsEngineHost>) {
+    #sourceEl: HTMLSourceElement | null = null;
+    #disconnect: AbortController | null = null;
+
+    constructor(...args: any[]) {
+      super(...args);
+
+      this.engine?.on(Hls.Events.MEDIA_ATTACHED, () => this.#init());
+      this.engine?.on(Hls.Events.MEDIA_DETACHED, () => this.#destroy());
+      this.engine?.on(Hls.Events.DESTROYING, () => this.#destroy());
+      this.engine?.on(Hls.Events.MANIFEST_LOADING, (_event, data) => {
+        if (this.#sourceEl) this.#sourceEl.src = data.url;
+      });
+    }
+
+    #init(): void {
+      this.#destroy();
+
+      const target = this.target;
+      if (!target || !isWebKitAirPlayCapable(target)) return;
+
+      // Counter the `disableRemotePlayback = true` that other code paths may
+      // set for MSE; AirPlay requires the picker to be available on this
+      // element.
+      target.disableRemotePlayback = false;
+      this.#attachSource(target);
+      this.#setupLoadControl(target);
+    }
+
+    #attachSource(target: WebKitVideoElement) {
+      this.#sourceEl = document.createElement('source');
+      this.#sourceEl.type = 'application/x-mpegURL';
+      this.#sourceEl.src = this.engine?.url ?? '';
+      target.append(this.#sourceEl);
+    }
+
+    #setupLoadControl(target: WebKitVideoElement) {
+      const sync = () => {
+        /*
+         * From HLS.loadStart "Depending on default config,
+         * client starts loading automatically when a source is set."
+         * Safari re-sets the source when we turn AirPlay off, so there
+         * is no need to call start load here when current playback
+         * target is not wireless.
+         */
+        if (target.webkitCurrentPlaybackTargetIsWireless) {
+          this.engine?.stopLoad();
+        }
+      };
+
+      this.#disconnect = new AbortController();
+      listen(target as EventTarget, 'webkitcurrentplaybacktargetiswirelesschanged', sync, {
+        signal: this.#disconnect.signal,
+      });
+
+      // AirPlay may already be active at (re)attach.
+      sync();
+    }
+
+    #destroy(): void {
+      this.#disconnect?.abort();
+      this.#disconnect = null;
+      this.#sourceEl?.remove();
+      this.#sourceEl = null;
+    }
+  }
+
+  return HlsJsMediaAirPlay as unknown as Base;
+}

packages/core/src/dom/media/hls-js/hls-js-only.ts

@@ -9,6 +9,7 @@ import type {
   MediaStreamTypeCapability,
 } from '../../../core/media/types';
 import { HTMLVideoElementHost } from '../video-host';
+import { HlsJsMediaAirPlayMixin } from './airplay-bridge';
 import { HlsJsMediaErrorsMixin } from './errors';
 import { HlsJsMediaLiveMixin } from './live';
 import { HlsJsMediaMediaTracksMixin } from './media-tracks';
@@ -73,12 +74,14 @@ interface HlsJsMediaCapabilities
   readonly error: MediaError | null;
 }
 
-const HlsJsOnlyMediaComposed = HlsJsMediaPreloadMixin(
-  HlsJsMediaLiveMixin(
-    HlsJsMediaStreamTypeMixin(
-      HlsJsMediaMediaTracksMixin(
-        HlsJsMediaMetadataTracksMixin(
-          HlsJsMediaTextTracksMixin(HlsJsMediaErrorsMixin(MediaTracksMixin(HlsJsOnlyMediaBase)))
+const HlsJsOnlyMediaComposed = HlsJsMediaAirPlayMixin(
+  HlsJsMediaPreloadMixin(
+    HlsJsMediaLiveMixin(
+      HlsJsMediaStreamTypeMixin(
+        HlsJsMediaMediaTracksMixin(
+          HlsJsMediaMetadataTracksMixin(
+            HlsJsMediaTextTracksMixin(HlsJsMediaErrorsMixin(MediaTracksMixin(HlsJsOnlyMediaBase)))
+          )
         )
       )
     )

packages/core/src/dom/media/hls-js/tests/airplay-bridge.test.ts

@@ -0,0 +1,198 @@
+import type { Constructor } from '@videojs/utils/types';
+import Hls from 'hls.js';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { HlsJsMediaAirPlayMixin } from '../airplay-bridge';
+import type { HlsEngineHost } from '../types';
+
+function createEngine(url = ''): Hls {
+  const listeners = new Map<string, Set<(...args: any[]) => void>>();
+  return {
+    url,
+    on(event: string, fn: (...args: any[]) => void) {
+      if (!listeners.has(event)) listeners.set(event, new Set());
+      listeners.get(event)!.add(fn);
+    },
+    off(event: string, fn: (...args: any[]) => void) {
+      listeners.get(event)?.delete(fn);
+    },
+    emit(event: string, ...args: any[]) {
+      for (const fn of listeners.get(event) ?? []) fn(event, ...args);
+    },
+    startLoad: vi.fn(),
+    stopLoad: vi.fn(),
+  } as unknown as Hls;
+}
+
+// The real engine host exposes `target` as a protected getter; the mixin reads
+// it internally. Here we model a minimal host with a writable `target` so tests
+// can simulate attachment, then bridge to the mixin's expected host shape.
+class FakeHost extends EventTarget {
+  engine: Hls | null;
+  target: HTMLMediaElement | null = null;
+
+  constructor(engine: Hls | null = null) {
+    super();
+    this.engine = engine;
+  }
+}
+
+const AirPlayHost = HlsJsMediaAirPlayMixin(
+  FakeHost as unknown as Constructor<HlsEngineHost>
+) as unknown as typeof FakeHost;
+
+function createVideo(initialWireless = false): HTMLVideoElement & { webkitCurrentPlaybackTargetIsWireless: boolean } {
+  const video = document.createElement('video') as HTMLVideoElement & {
+    webkitCurrentPlaybackTargetIsWireless: boolean;
+  };
+  let wireless = initialWireless;
+  Object.defineProperty(video, 'webkitCurrentPlaybackTargetIsWireless', {
+    configurable: true,
+    get: () => wireless,
+    set: (v: boolean) => {
+      wireless = v;
+    },
+  });
+  return video;
+}
+
+describe('HlsJsMediaAirPlayMixin', () => {
+  beforeEach(() => {
+    // Stub the WebKit AirPlay capability check (jsdom lacks it).
+    (globalThis as any).WebKitPlaybackTargetAvailabilityEvent = class {};
+  });
+
+  afterEach(() => {
+    delete (globalThis as any).WebKitPlaybackTargetAvailabilityEvent;
+  });
+
+  it('appends a fallback <source> element on MEDIA_ATTACHED', () => {
+    const engine = createEngine('https://example.com/master.m3u8');
+    const host = new AirPlayHost(engine);
+    const video = createVideo();
+    host.target = video;
+
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+
+    const source = video.querySelector('source');
+    expect(source).not.toBeNull();
+    expect(source?.type).toBe('application/x-mpegURL');
+    expect(source?.src).toContain('master.m3u8');
+  });
+
+  it('sets disableRemotePlayback = false on the target', () => {
+    const engine = createEngine();
+    const host = new AirPlayHost(engine);
+    const video = createVideo();
+    video.disableRemotePlayback = true;
+    host.target = video;
+
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+
+    expect(video.disableRemotePlayback).toBe(false);
+  });
+
+  it('updates the <source> src on MANIFEST_LOADING', () => {
+    const engine = createEngine('https://example.com/old.m3u8');
+    const host = new AirPlayHost(engine);
+    const video = createVideo();
+    host.target = video;
+
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+    (engine as any).emit(Hls.Events.MANIFEST_LOADING, { url: 'https://example.com/new.m3u8' });
+
+    expect(video.querySelector('source')?.src).toContain('new.m3u8');
+  });
+
+  it('calls stopLoad when AirPlay activates', () => {
+    const engine = createEngine();
+    const host = new AirPlayHost(engine);
+    const video = createVideo();
+    host.target = video;
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+    (engine.stopLoad as ReturnType<typeof vi.fn>).mockClear();
+    (engine.startLoad as ReturnType<typeof vi.fn>).mockClear();
+
+    video.webkitCurrentPlaybackTargetIsWireless = true;
+    video.dispatchEvent(new Event('webkitcurrentplaybacktargetiswirelesschanged'));
+
+    expect(engine.stopLoad).toHaveBeenCalled();
+    expect(engine.startLoad).not.toHaveBeenCalled();
+  });
+
+  it('does not call startLoad when AirPlay deactivates', () => {
+    // Safari re-sets the source when AirPlay turns off, so hls.js resumes
+    // loading on its own — the bridge never calls startLoad.
+    const engine = createEngine();
+    const host = new AirPlayHost(engine);
+    const video = createVideo(true);
+    host.target = video;
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+    (engine.startLoad as ReturnType<typeof vi.fn>).mockClear();
+
+    video.webkitCurrentPlaybackTargetIsWireless = false;
+    video.dispatchEvent(new Event('webkitcurrentplaybacktargetiswirelesschanged'));
+
+    expect(engine.startLoad).not.toHaveBeenCalled();
+  });
+
+  it('never calls startLoad across the connect burst', () => {
+    // WebKit fires `true → false → true` on first connect. The transient
+    // `false` must not resume loading against the MSE mid-handoff; the bridge
+    // only ever suspends, so startLoad is never called.
+    const engine = createEngine();
+    const host = new AirPlayHost(engine);
+    const video = createVideo();
+    host.target = video;
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+    (engine.startLoad as ReturnType<typeof vi.fn>).mockClear();
+
+    for (const wireless of [true, false, true]) {
+      video.webkitCurrentPlaybackTargetIsWireless = wireless;
+      video.dispatchEvent(new Event('webkitcurrentplaybacktargetiswirelesschanged'));
+    }
+
+    expect(engine.startLoad).not.toHaveBeenCalled();
+  });
+
+  it('suspends loading when AirPlay is already active at attach', () => {
+    const engine = createEngine();
+    const host = new AirPlayHost(engine);
+    const video = createVideo(true);
+    host.target = video;
+
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+
+    expect(engine.stopLoad).toHaveBeenCalled();
+  });
+
+  it('removes the <source> and stops listening on MEDIA_DETACHED', () => {
+    const engine = createEngine();
+    const host = new AirPlayHost(engine);
+    const video = createVideo();
+    host.target = video;
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+
+    (engine as any).emit(Hls.Events.MEDIA_DETACHED);
+
+    expect(video.querySelector('source')).toBeNull();
+
+    (engine.stopLoad as ReturnType<typeof vi.fn>).mockClear();
+    video.webkitCurrentPlaybackTargetIsWireless = true;
+    video.dispatchEvent(new Event('webkitcurrentplaybacktargetiswirelesschanged'));
+    expect(engine.stopLoad).not.toHaveBeenCalled();
+  });
+
+  it('no-ops when target lacks WebKit AirPlay APIs', () => {
+    delete (globalThis as any).WebKitPlaybackTargetAvailabilityEvent;
+    const engine = createEngine();
+    const host = new AirPlayHost(engine);
+    const video = document.createElement('video');
+    host.target = video;
+
+    (engine as any).emit(Hls.Events.MEDIA_ATTACHED);
+
+    expect(video.querySelector('source')).toBeNull();
+    expect(engine.stopLoad).not.toHaveBeenCalled();
+    expect(engine.startLoad).not.toHaveBeenCalled();
+  });
+});

packages/core/src/dom/media/video-host.ts

@@ -38,6 +38,10 @@ export class HTMLVideoElementHost extends HTMLMediaElementHost<HTMLVideoTargetLi
     setProp(this, 'disablePictureInPicture', value);
   }
 
+  get webkitCurrentPlaybackTargetIsWireless() {
+    return (this.target as WebKitVideoElement | null)?.webkitCurrentPlaybackTargetIsWireless;
+  }
+
   get webkitPresentationMode() {
     return (this.target as WebKitVideoElement | null)?.webkitPresentationMode;
   }

packages/utils/src/dom/index.ts

@@ -44,7 +44,6 @@ export type {
 export {
   isWebKitAirPlayCapable,
   supportsWebKitAirPlay,
-  type WebKitAirPlayMedia,
   type WebKitDocument,
   type WebKitFullscreenElement,
   type WebKitPresentationMode,

packages/utils/src/dom/webkit.ts

@@ -1,13 +1,10 @@
-/** WebKit-only addition to HTMLMediaElement exposing the active AirPlay flag. */
-export interface WebKitAirPlayMedia extends HTMLMediaElement {
-  readonly webkitCurrentPlaybackTargetIsWireless: boolean;
-}
-
 /** WebKit presentation mode values for iOS Safari. */
 export type WebKitPresentationMode = 'inline' | 'fullscreen' | 'picture-in-picture';
 
 /** Extended HTMLVideoElement with WebKit vendor APIs. */
 export interface WebKitVideoElement extends HTMLVideoElement {
+  /**  Whether the current playback target is wireless (WebKit) */
+  webkitCurrentPlaybackTargetIsWireless?: boolean;
   /** Current WebKit presentation mode (iOS Safari). */
   webkitPresentationMode?: WebKitPresentationMode;
   /** Set WebKit presentation mode (iOS Safari). */
@@ -39,6 +36,6 @@ export function supportsWebKitAirPlay(): boolean {
 }
 
 /** Whether `media` exposes WebKit's AirPlay APIs. */
-export function isWebKitAirPlayCapable(media: EventTarget): media is WebKitAirPlayMedia {
+export function isWebKitAirPlayCapable(media: EventTarget): media is WebKitVideoElement {
   return supportsWebKitAirPlay() && 'webkitCurrentPlaybackTargetIsWireless' in media;
 }