Fix YouTube relay instabile e timer LIVE a zero in app

ffmpeg: probesize/analyzeduration su _air, restart più rapido e avvio relay
al go_live. App: sincronizza started_at dal server e fallback al passaggio live.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app/services/mediamtx/publisher_sync.rb

@@ -17,7 +17,9 @@ module Mediamtx
           # RTMP ancora connesso in pausa: non forzare live/reconnect.
         elsif @session.may_go_live?
           @session.go_live!
-          Streams::Overlay::Refresh.call(@session.reload)
+          @session.reload
+          Streams::Overlay::Refresh.call(@session)
+          Streams::YoutubeRelay.ensure_publishing!(@session) if @session.platform == "youtube"
         elsif @session.reconnecting? && @session.may_reconnect?
           @session.reconnect!
           cancel_timeout

backend/app/services/streams/youtube_relay.rb

@@ -56,10 +56,13 @@ module Streams
         return if session.stream_key.blank?
         return unless Streams::OverlayRelay.running?(session.id)
 
+        pid = pid_for(session.id)
+        clear_pid(session.id) if pid.present? && !process_alive?(pid.to_i)
+
         return if running?(session.id)
 
         last_restart = redis.get(restart_debounce_key(session.id)).to_i
-        return if last_restart.positive? && (Time.now.to_i - last_restart) < 20
+        return if last_restart.positive? && (Time.now.to_i - last_restart) < 5
 
         start(session)
         redis.set(restart_debounce_key(session.id), Time.now.to_i, ex: 300)
@@ -75,6 +78,7 @@ module Streams
         [
           "ffmpeg", "-nostdin", "-hide_banner", "-loglevel", "warning",
           "-fflags", "+genpts+discardcorrupt", "-use_wallclock_as_timestamps", "1",
+          "-analyzeduration", "10000000", "-probesize", "10000000",
           "-rw_timeout", "15000000",
           "-i", intake,
           "-f", "lavfi", "-i", "anullsrc=channel_layout=mono:sample_rate=48000",

mobile/lib/features/camera_mode/camera_screen.dart

@@ -41,6 +41,7 @@ class _CameraScreenState extends ConsumerState<CameraScreen> {
   static const _previewKey = ValueKey<String>('camera_streaming_preview');
 
   Timer? _elapsedTimer;
+  Timer? _sessionSyncTimer;
   Timer? _telemetryTimer;
   Timer? _statsTimer;
   Timer? _scorePullTimer;
@@ -75,6 +76,9 @@ class _CameraScreenState extends ConsumerState<CameraScreen> {
             );
       }
     });
+    _sessionSyncTimer = Timer.periodic(const Duration(seconds: 15), (_) {
+      unawaited(_syncSessionStartedAt());
+    });
     _telemetryTimer = Timer.periodic(const Duration(seconds: 10), (_) => _sendTelemetry());
     _statsTimer = Timer.periodic(const Duration(seconds: 30), (_) => _fetchStats());
     _scorePullTimer = Timer.periodic(const Duration(seconds: 2), (_) {
@@ -263,6 +267,20 @@ class _CameraScreenState extends ConsumerState<CameraScreen> {
     } catch (_) {}
   }
 
+  /// Il server imposta `started_at` solo al primo go_live; sincronizza per il timer LIVE.
+  Future<void> _syncSessionStartedAt() async {
+    final current = ref.read(sessionProvider).session;
+    if (current == null || current.startedAt != null || !current.isLive) return;
+    try {
+      final fresh = await ref.read(apiClientProvider).fetchSession(widget.sessionId);
+      if (!mounted || fresh.startedAt == null) return;
+      ref.read(sessionProvider.notifier).setSession(
+            fresh,
+            match: ref.read(sessionProvider).match,
+          );
+    } catch (_) {}
+  }
+
   Future<void> _lockOrientations() async {
     await SystemChrome.setPreferredOrientations([
       DeviceOrientation.landscapeLeft,
@@ -497,6 +515,7 @@ class _CameraScreenState extends ConsumerState<CameraScreen> {
   @override
   void dispose() {
     _elapsedTimer?.cancel();
+    _sessionSyncTimer?.cancel();
     _telemetryTimer?.cancel();
     _statsTimer?.cancel();
     _scorePullTimer?.cancel();

mobile/lib/providers/session_provider.dart

@@ -111,6 +111,8 @@ class SessionNotifier extends StateNotifier<SessionState> {
         state = state.copyWith(cameraDevice: device);
         return;
       }
+      final startedAt = s.startedAt ??
+          ((incoming == 'live' || incoming == 'reconnecting') ? DateTime.now() : null);
       state = state.copyWith(
         session: StreamSession(
           id: s.id,
@@ -127,7 +129,7 @@ class SessionNotifier extends StateNotifier<SessionState> {
           privacyStatus: s.privacyStatus,
           qualityPreset: s.qualityPreset,
           targetBitrate: s.targetBitrate,
-          startedAt: s.startedAt,
+          startedAt: startedAt,
           disconnectionCount: s.disconnectionCount,
           score: s.score,
           devices: s.devices,