yt-dlp cookies: from a browser or a file (cookies.txt or extension JSON), per site, private; server --yt-dlp-cookies

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/desktop/lib/src/playback/playback_controller.dart

@@ -16,7 +16,7 @@ import '../sync/state_diff.dart';
 import '../sync/user_seek.dart';
 import 'frame_watchdog.dart';
 import 'media_marks.dart';
-import 'yt_dlp_app.dart' show ytdlFormat;
+import 'yt_dlp_app.dart' show AppYtDlp, ytdlFormat;
 
 /// Owns one mpv [Player] (and its [VideoController]) per session: created
 /// by [init] on join, released by [dispose] on leave, swapped by
@@ -65,21 +65,31 @@ class PlaybackController {
   void Function(String error)? onYtdlError;
 
   /// Points mpv's yt-dlp hook at [path] (the app's managed copy) for web
-  /// page links, at most 1080p. Once per player.
+  /// page links, at most 1080p, once per player; its cookies
+  /// (`ytdl-raw-options`) whenever they changed.
   Future<void> useYtDlp(String path) async {
     final p = _player;
-    if (p == null || identical(p, _ytdlSetOn)) return;
+    if (p == null) return;
     try {
       final dynamic platform = p.platform;
-      await platform?.setProperty('script-opts', 'ytdl_hook-ytdl_path=$path');
-      await platform?.setProperty('ytdl-format', ytdlFormat);
-      _ytdlSetOn = p;
+      if (!identical(p, _ytdlSetOn)) {
+        await platform?.setProperty('script-opts', 'ytdl_hook-ytdl_path=$path');
+        await platform?.setProperty('ytdl-format', ytdlFormat);
+        _ytdlSetOn = p;
+        _ytdlRaw = '';
+      }
+      final raw = await AppYtDlp.instance.mpvRawOptions();
+      if (raw != _ytdlRaw && identical(p, _player)) {
+        await platform?.setProperty('ytdl-raw-options', raw);
+        _ytdlRaw = raw;
+      }
     } catch (e) {
       debugPrint('yt-dlp path not set: $e');
     }
   }
 
   Player? _ytdlSetOn;
+  String _ytdlRaw = '';
 
   /// Fingerprint of the picture on screen, installed by the video view
   /// (`ShownFrameProbe.sample`). Without it the watchdog stays idle.

apps/desktop/lib/src/playback/yt_dlp_app.dart

@@ -28,6 +28,16 @@ class AppYtDlp {
   /// update check afterwards).
   void warmUp() => unawaited(ytDlp.then((y) => y.ensure()).catchError((_) => null));
 
+  /// mpv's `ytdl-raw-options` for the cookies in the yt-dlp folder ('' for
+  /// none; see [YtDlpCookies]).
+  Future<String> mpvRawOptions() async {
+    try {
+      return (await ytDlp).cookies.mpvRawOptions();
+    } catch (_) {
+      return '';
+    }
+  }
+
   final _probes = <String, (DateTime, Future<LinkProbe>)>{};
   static const _probeTtl = Duration(minutes: 10);