Turn the transmuxing worker back off: it is webpack-only

apps/web/src/client/tv.js

@@ -82,14 +82,32 @@ export function isTvBrowser(userAgent) {
 export function playerConfig(_isTv) {
   return {
     /*
-     * Demux on a worker thread.
+     * NOT on a worker thread, and this one is a trap worth the paragraph.
      *
-     * A transport stream at broadcast bitrate is real work, and on the main
-     * thread it competes with rendering the page it is playing on -- which
-     * shows up as dropped frames rather than as an error. mpegts.js builds the
-     * worker from a blob URL; we serve no CSP, so there is nothing to allow.
+     * Demuxing a broadcast-bitrate transport stream on the main thread competes
+     * with rendering the page it is playing on, so `enableWorker: true` looks
+     * like free performance, and media-streamer's live TV player does set it.
+     * It cannot be copied here.
+     *
+     * mpegts.js builds its worker by STRINGIFYING `__webpack_modules__` --
+     * webpack's internal module registry -- in `utils/webworkify-webpack.js`.
+     * That global exists in media-streamer, which is Next.js and therefore
+     * webpack. This bundle is built by Bun, where there is no such global, so
+     * the worker it assembles is broken.
+     *
+     * And it fails in the worst available way. `Transmuxer` wraps the worker
+     * setup in a try/catch and falls back to inline transmuxing -- but only a
+     * SYNCHRONOUS throw reaches that catch. A Worker that constructs from a
+     * blob whose body then fails is an asynchronous failure: nothing throws,
+     * nothing falls back, the init segment never arrives, and the player sits
+     * there having reported no error at all. That is not a dropped frame, it is
+     * "the stream does not play", which is what shipping this caused.
+     *
+     * Everything else in this profile came over from the television's, which
+     * had been running in production for weeks. This was the one line that had
+     * never run anywhere but under webpack.
      */
-    enableWorker: true,
+    enableWorker: false,
 
     /*
      * Read ahead, on every screen.

test/player-codecs.test.js

@@ -307,11 +307,25 @@ describe('the buffering profile follows the screen', () => {
     expect(config.stashInitialSize).toBe(384 * 1024);
   });
 
-  test('the demuxer runs off the main thread', () => {
-    // Broadcast-bitrate demuxing competes with rendering the page it plays on,
-    // and loses as dropped frames rather than as an error. We serve no CSP, so
-    // mpegts.js can build its blob worker unimpeded.
-    expect(playerConfig(false).enableWorker).toBe(true);
+  test('the demuxer does NOT run off the main thread', () => {
+    /*
+     * A regression test with a real outage behind it.
+     *
+     * `enableWorker: true` reads like free performance and media-streamer's
+     * live TV player does set it, so it was copied over -- and every stream
+     * stopped playing. mpegts.js builds its worker by stringifying
+     * `__webpack_modules__`, webpack's internal module registry. media-streamer
+     * is Next.js, so that global is there. This bundle is built by Bun, so it
+     * is not, and the worker is broken.
+     *
+     * The failure is silent: Transmuxer's try/catch only sees a SYNCHRONOUS
+     * throw, and a Worker that constructs from a bad blob fails asynchronously.
+     * Nothing throws, nothing falls back to inline transmuxing, no init segment
+     * ever arrives, and the player reports no error at all.
+     *
+     * Do not turn this on again without changing how this file is bundled.
+     */
+    expect(playerConfig(false).enableWorker).toBe(false);
   });
 
   test('both profiles still drop what has been watched, and never idle', () => {