fix(watch): drop the Web Audio reroute, keep Media Session for iOS background audio (0.57.2)

Reported: on iPad Brave a shared video's audio still stopped when backgrounded, while youtube.com
keeps playing. Root cause: routing the element's audio through createMediaElementSource pulls it out
of the normal media pipeline the browser's background-playback feature (and iOS) hooks into, and iOS
then suspends the AudioContext on background — the opposite of the goal. YouTube uses a plain media
element + Media Session and lets the browser background it. So drop the Web Audio graph entirely and
keep only the Media Session metadata + play/pause handlers, leaving native background handling in
charge. Frontend-only.

VERSION

@@ -1 +1 @@
-0.57.1
+0.57.2

frontend/src/components/WatchPage.tsx

@@ -5,57 +5,19 @@ import { Download, Link2, Lock, PlayCircle } from "lucide-react";
 // tree (no auth, no providers) — like the /privacy and /terms pages. Uses plain fetch and a tiny
 // self-contained i18n dict (the public viewer has no app language preference).
 
-// Keep audio playing when the page is backgrounded (iOS Safari/Brave otherwise suspend a <video>
-// the moment you leave the tab — the "background playback" a native app / YouTube Premium gets). Two
-// pieces: (1) route the element's audio through a Web Audio graph — once that graph is live, iOS
-// keeps the audio session running in the background while the video frame freezes; (2) Media Session
-// metadata + handlers, which give lock-screen controls AND signal the OS that media is active. The
-// file is same-origin (served by us), so createMediaElementSource isn't CORS-tainted. All of it is
-// best-effort: any unsupported bit falls back to the plain <video>. Set up lazily on the first play
-// (a user gesture — required to create/resume an AudioContext) and only once (a second
-// createMediaElementSource on the same element throws).
-function useBackgroundAudio(
+// Advertise the playing video to the OS via the Media Session API: lock-screen / control-center
+// metadata + play/pause handlers. This is also what lets a browser's own "background playback"
+// feature keep the audio going when the page is backgrounded — it's exactly how youtube.com stays
+// playing in the background on Brave iOS. We deliberately do NOT route the audio through the Web
+// Audio API: `createMediaElementSource` pulls the element out of the normal media pipeline that the
+// background feature (and iOS) hooks into, and iOS then suspends the AudioContext on background —
+// which STOPPED playback instead of keeping it alive (measured on iPad Brave). A plain <video> +
+// MediaSession leaves the browser's native background handling in charge.
+function useMediaSession(
   videoRef: React.RefObject<HTMLVideoElement | null>,
   meta: Meta | null,
   ready: boolean,
 ) {
-  const ctxRef = useRef<AudioContext | null>(null);
-  const wiredRef = useRef(false);
-
-  useEffect(() => {
-    const video = videoRef.current;
-    if (!video || !ready) return;
-    // Only iOS suspends a backgrounded <video> — and only there does rerouting the audio through
-    // Web Audio buy anything. Every other platform backgrounds media audio natively, so we leave
-    // their <video> untouched rather than risk the reroute leaving foreground audio silent if the
-    // AudioContext can't resume. (iPadOS reports as MacIntel + touch.)
-    const isIOS =
-      /iP(hone|ad|od)/.test(navigator.userAgent) ||
-      (navigator.platform === "MacIntel" && navigator.maxTouchPoints > 1);
-    if (!isIOS) return;
-    const wire = () => {
-      if (wiredRef.current) {
-        ctxRef.current?.resume().catch(() => {});
-        return;
-      }
-      try {
-        const Ctx =
-          window.AudioContext ||
-          (window as unknown as { webkitAudioContext?: typeof AudioContext }).webkitAudioContext;
-        if (!Ctx) return;
-        const ctx = new Ctx();
-        ctx.createMediaElementSource(video).connect(ctx.destination);
-        ctxRef.current = ctx;
-        wiredRef.current = true;
-        ctx.resume().catch(() => {});
-      } catch {
-        /* unsupported / already wired — plain <video> still plays, just not in the background */
-      }
-    };
-    video.addEventListener("play", wire);
-    return () => video.removeEventListener("play", wire);
-  }, [videoRef, ready]);
-
   useEffect(() => {
     if (!ready || !meta || !("mediaSession" in navigator)) return;
     const video = videoRef.current;
@@ -73,15 +35,6 @@ function useBackgroundAudio(
       /* MediaMetadata / handlers unsupported — ignore */
     }
   }, [ready, meta, videoRef]);
-
-  // Recover if the context gets suspended (e.g. iOS suspends it on background) once we're back.
-  useEffect(() => {
-    const onVisible = () => {
-      if (document.visibilityState === "visible") ctxRef.current?.resume().catch(() => {});
-    };
-    document.addEventListener("visibilitychange", onVisible);
-    return () => document.removeEventListener("visibilitychange", onVisible);
-  }, []);
 }
 
 type Meta = {
@@ -160,7 +113,7 @@ export default function WatchPage() {
   const [error, setError] = useState<string | null>(null);
   const [unlocking, setUnlocking] = useState(false);
   const videoRef = useRef<HTMLVideoElement>(null);
-  useBackgroundAudio(videoRef, meta, status === "ready");
+  useMediaSession(videoRef, meta, status === "ready");
 
   useEffect(() => {
     if (!token) {

frontend/src/lib/releaseNotes.ts

@@ -14,6 +14,13 @@ export interface ReleaseEntry {
 }
 
 export const RELEASE_NOTES: ReleaseEntry[] = [
+  {
+    version: "0.57.2",
+    date: "2026-07-28",
+    chores: [
+      "Sharing: the shared-video page now advertises playback to the OS via the Media Session API only, dropping a Web Audio workaround that interfered with the browser's own background playback on iOS (it left the audio to be suspended when the tab was backgrounded, the opposite of the goal) — so background audio is left to the browser's native handling, the way it works for youtube.com.",
+    ],
+  },
   {
     version: "0.57.1",
     date: "2026-07-28",