fix: stabilize IPTV playback and implement request throttling

- Add playback lock to XtreamService to delay EPG during stream init
- Increase MPEG-TS stash buffer to 512KB for better stability
- Enable liveBufferLatencyChasing to prevent stream drift
- Tune HLS parameters for balanced speed and reliability

lib/features/iptv/screens/player_screen.dart

@@ -140,6 +140,12 @@ class _PlayerScreenState extends ConsumerState<PlayerScreen> {
         streamUrl = service.getLiveStreamUrlTs(currentStreamId);
       }
 
+      // STABILIZATION: Lock background requests during stream init
+      service.isPlaybackLoading = true;
+      Future.delayed(const Duration(seconds: 10), () {
+        service.isPlaybackLoading = false;
+      });
+
       _currentStreamUrl = streamUrl;
 
       final encodedUrl = Uri.encodeComponent(streamUrl);

lib/features/iptv/services/xtream_service.dart

@@ -15,6 +15,13 @@ class XtreamService {
 
   PlaylistConfig? _currentPlaylist;
 
+  /// Flag to indicate that a playback is currently loading
+  /// Used to throttle background requests (EPG, images)
+  bool isPlaybackLoading = false;
+
+  /// Minimum delay for background requests when playback is loading
+  static const _throttleDelay = Duration(seconds: 8);
+
   XtreamService() {
     _dio = Dio(
       BaseOptions(
@@ -616,6 +623,11 @@ class XtreamService {
   Future<List<EpgEntry>> getShortEpg(String streamId) async {
     if (_currentPlaylist == null) throw Exception('No playlist configured');
 
+    if (isPlaybackLoading) {
+      debugPrint('[XtreamService] Throttling short EPG for $streamId');
+      await Future.delayed(_throttleDelay);
+    }
+
     try {
       final response = await _dio.get(
         _wrapWithProxy(_currentPlaylist!.apiBaseUrl),
@@ -653,6 +665,11 @@ class XtreamService {
   Future<xm.ShortEPG> getShortEPG(String streamId) async {
     if (_currentPlaylist == null) throw Exception('No playlist configured');
 
+    if (isPlaybackLoading) {
+      debugPrint('[XtreamService] Throttling short EPG metadata for $streamId');
+      await Future.delayed(_throttleDelay);
+    }
+
     try {
       final response = await _dio.get(
         _wrapWithProxy(_currentPlaylist!.apiBaseUrl),

web/player.html

@@ -253,15 +253,15 @@
             const isTurbo = urlParams.get('turbo') === 'true';
 
             const hls = new Hls({
-                maxBufferLength: isTurbo ? 30 : 45,
+                maxBufferLength: isTurbo ? 45 : 50,
                 enableWorker: true,
-                liveSyncDurationCount: isTurbo ? 2 : 4,
+                liveSyncDurationCount: isTurbo ? 3 : 4, // Improved stability
                 // Turbo-Start specific
                 startLevel: isTurbo ? 0 : -1,
                 initialLiveManifestSize: 1,
                 abrEwmaDefaultEstimate: 500000,
-                manifestLoadingRetryDelay: 500,
-                levelLoadingRetryDelay: 500
+                manifestLoadingRetryDelay: 800,
+                levelLoadingRetryDelay: 800
             });
             window.hlsInstance = hls;
             hls.loadSource(url);

web/player_lite.html

@@ -245,18 +245,18 @@
             const isTurbo = urlParams.get('turbo') === 'true';
 
             const hls = new Hls({
-                maxBufferLength: isTurbo ? 30 : 60,
-                maxMaxBufferLength: isTurbo ? 60 : 120,
+                maxBufferLength: isTurbo ? 45 : 60,
+                maxMaxBufferLength: isTurbo ? 90 : 120,
                 enableWorker: true,
-                liveSyncDurationCount: isTurbo ? 2 : 5, // Aggressive sync for Turbo
-                liveMaxLatencyDurationCount: isTurbo ? 10 : 15,
+                liveSyncDurationCount: isTurbo ? 3 : 5, // Improved stability
+                liveMaxLatencyDurationCount: isTurbo ? 15 : 20,
                 lowLatencyMode: true,
                 // Turbo-Start specific
-                startLevel: isTurbo ? 0 : -1, // Lowest bitrate first
+                startLevel: isTurbo ? 0 : -1,
                 initialLiveManifestSize: 1,
-                abrEwmaDefaultEstimate: 500000, // Start with conservative estimate
-                manifestLoadingRetryDelay: 500,
-                levelLoadingRetryDelay: 500
+                abrEwmaDefaultEstimate: 500000,
+                manifestLoadingRetryDelay: 800,
+                levelLoadingRetryDelay: 800
             });
 
             window.hlsInstance = hls;
@@ -292,9 +292,12 @@
                 url: url
             }, {
                 enableWorker: true,
-                stashInitialSize: isTurbo ? 128 * 1024 : 512 * 1024, // Tiny stash for Turbo zapping
-                enableStashBuffer: !isTurbo, // Direct pass-through for Live TV Turbo
-                lazyLoad: false
+                stashInitialSize: isTurbo ? 512 * 1024 : 1024 * 1024, // 512KB for better stability
+                enableStashBuffer: true, // Re-enable stash buffer for stability
+                liveBufferLatencyChasing: true, // Correct drift
+                liveBufferLatencyChasingOnPaused: true,
+                lazyLoad: false,
+                maxStashSize: 1024 * 1024 // 1MB Max
             });
 
             player.attachMediaElement(video);

web/player_mobile.html

@@ -231,18 +231,18 @@
                 const isTurbo = urlParams.get('turbo') === 'true';
 
                 const hls = new Hls({
-                    maxBufferLength: isTurbo ? 30 : 60,
-                    maxMaxBufferLength: isTurbo ? 60 : 120,
-                    liveSyncDurationCount: isTurbo ? 2 : 5,
-                    liveMaxLatencyDurationCount: isTurbo ? 10 : 15,
+                    maxBufferLength: isTurbo ? 45 : 60,
+                    maxMaxBufferLength: isTurbo ? 90 : 120,
+                    liveSyncDurationCount: isTurbo ? 3 : 5, // Improved stability
+                    liveMaxLatencyDurationCount: isTurbo ? 15 : 20,
                     enableWorker: true,
-                    lowLatencyMode: !isTurbo, // Prioritize stability unless Turbo requested
+                    lowLatencyMode: true,
                     // Turbo-Start specific
                     startLevel: isTurbo ? 0 : -1,
                     initialLiveManifestSize: 1,
                     abrEwmaDefaultEstimate: 500000,
-                    manifestLoadingRetryDelay: 500,
-                    levelLoadingRetryDelay: 500
+                    manifestLoadingRetryDelay: 800,
+                    levelLoadingRetryDelay: 800
                 });
                 hls.loadSource(streamUrl);
                 hls.attachMedia(video);