Fix BIF scrub preview aspect ratio and raise desktop size limit

lib/media/media_source_info.dart

@@ -25,6 +25,9 @@ class MediaSourceInfo {
   /// null here and uses [partId] + the BIF service instead.
   final Map<int, TrickplayInfo>? trickplayByWidth;
 
+  /// Display aspect ratio of the video stream (width / height).
+  final double? videoAspectRatio;
+
   MediaSourceInfo({
     required this.videoUrl,
     required this.audioTracks,
@@ -36,6 +39,7 @@ class MediaSourceInfo {
     this.defaultAudioStreamIndex,
     this.defaultSubtitleStreamIndex,
     this.trickplayByWidth,
+    this.videoAspectRatio,
   });
   int? getPartId() => partId;
 }

lib/services/bif_thumbnail_service.dart

@@ -4,6 +4,7 @@ import 'dart:typed_data';
 import 'plex_client.dart';
 import 'scrub_preview_source.dart';
 import '../utils/app_logger.dart';
+import '../utils/platform_detector.dart';
 
 /// A single BIF thumbnail entry: timestamp in milliseconds + JPEG bytes.
 typedef BifEntry = ({int timestampMs, Uint8List imageBytes});
@@ -66,14 +67,20 @@ List<BifEntry> _parseBifBytes(Uint8List bytes) {
 class BifThumbnailService implements ScrubPreviewSource {
   List<BifEntry>? _entries;
 
+  double? _aspectRatio;
+
   /// Download and parse the BIF file for [partId].
   /// Returns silently on failure (thumbnails simply won't be available).
-  Future<void> load(PlexClient client, int partId) async {
+  Future<void> load(PlexClient client, int partId, {double? aspectRatio}) async {
+    _aspectRatio = aspectRatio;
     _entries = null;
     try {
       final bytes = await client.downloadBifFile(partId);
       if (bytes == null || bytes.isEmpty) return;
-      if (bytes.length > 50 * 1024 * 1024) {
+      const fiftyMb = 50 * 1024 * 1024;
+      const twoHundredMb = 200 * 1024 * 1024;
+      final maxBytes = PlatformDetector.isDesktopOS() ? twoHundredMb : fiftyMb;
+      if (bytes.length > maxBytes) {
         appLogger.w('BIF file too large (${bytes.length} bytes), skipping');
         return;
       }
@@ -91,7 +98,7 @@ class BifThumbnailService implements ScrubPreviewSource {
   ScrubFrame? getFrame(Duration time) {
     final bytes = getThumbnail(time);
     if (bytes == null) return null;
-    return BytesScrubFrame(bytes);
+    return BytesScrubFrame(bytes, aspectRatio: _aspectRatio ?? 16 / 9);
   }
 
   /// Return the JPEG bytes for the thumbnail nearest to [time].

lib/services/plex_client.dart

@@ -3505,7 +3505,7 @@ class PlexClient
     if (partId == null) return null;
     final service = BifThumbnailService();
     try {
-      await service.load(this, partId);
+      await service.load(this, partId, aspectRatio: mediaSource.videoAspectRatio);
       return service;
     } catch (e, st) {
       appLogger.w('BIF thumbnail load failed for part $partId', error: e, stackTrace: st);

lib/services/plex_playback_mapper.dart

@@ -59,6 +59,7 @@ PlexVideoPlaybackData parsePlexVideoPlaybackDataFromJson(
             chapters: chapters,
             partId: part['id'] as int?,
             displayCriteria: PlexMappers.displayCriteriaFromJson(media as Map<String, dynamic>?, streams.videoStream),
+            videoAspectRatio: ((media as Map?)?['aspectRatio'] as num?)?.toDouble(),
           );
         }
       }

lib/services/scrub_preview_source.dart

@@ -17,9 +17,7 @@ sealed class ScrubFrame {
   double get aspectRatio;
 }
 
-/// Plex BIF: standalone JPEG bytes ready for [Image.memory]. Plex doesn't
-/// expose per-BIF dimensions out-of-band; servers virtually always use
-/// 16:9, which matches the default tooltip box.
+/// Plex BIF: standalone JPEG bytes ready for [Image.memory].
 class BytesScrubFrame extends ScrubFrame {
   final Uint8List bytes;
   @override