fix(jellyfin): avoid side-loading negotiated subtitles

lib/services/file_info_parser.dart

@@ -22,6 +22,8 @@ typedef JellyfinStreamFields = ({
   String? displayTitle,
   bool isDefault,
   bool isForced,
+  bool isExternalFile,
+  bool usesExternalDelivery,
   bool isExternal,
   String? deliveryUrl,
   int? channels,
@@ -30,7 +32,8 @@ typedef JellyfinStreamFields = ({
 
 JellyfinStreamFields parseJellyfinStreamFields(Map<String, dynamic> s, {int fallbackIndex = 0}) {
   final deliveryMethod = (s['DeliveryMethod'] as String?)?.toLowerCase();
-  final isExternal = deliveryMethod != null ? deliveryMethod == 'external' : s['IsExternal'] == true;
+  final isExternalFile = s['IsExternal'] == true;
+  final usesExternalDelivery = deliveryMethod == 'external';
   return (
     type: (s['Type'] as String?)?.toLowerCase(),
     index: flexibleInt(s['Index']) ?? fallbackIndex,
@@ -41,7 +44,9 @@ JellyfinStreamFields parseJellyfinStreamFields(Map<String, dynamic> s, {int fall
     displayTitle: s['DisplayTitle'] as String?,
     isDefault: s['IsDefault'] as bool? ?? false,
     isForced: s['IsForced'] as bool? ?? false,
-    isExternal: isExternal,
+    isExternalFile: isExternalFile,
+    usesExternalDelivery: usesExternalDelivery,
+    isExternal: isExternalFile || usesExternalDelivery,
     deliveryUrl: s['DeliveryUrl'] as String?,
     channels: flexibleInt(s['Channels']),
     frameRate: flexibleDouble(s['RealFrameRate']) ?? flexibleDouble(s['AverageFrameRate']),
@@ -231,7 +236,8 @@ class JellyfinFileInfoStreamReader implements FileInfoStreamReader {
       selected: f.isDefault,
       forced: f.isForced,
       key: f.isExternal ? f.deliveryUrl : null,
-      external: f.isExternal,
+      external: f.isExternalFile,
+      usesExternalDelivery: f.usesExternalDelivery,
     );
   }
 }

lib/services/jellyfin_client/parts/images_downloads.dart

@@ -89,7 +89,7 @@ mixin _JellyfinImageDownloadMethods on MediaServerCacheMixin {
               if (raw is! Map<String, dynamic>) continue;
               if (raw['Type'] != 'Subtitle') continue;
               final fields = parseJellyfinStreamFields(raw);
-              if (!fields.isExternal) continue;
+              if (!fields.isExternalFile) continue;
               final index = raw['Index'];
               if (index is! int) continue;
               final codec = fields.codec?.toLowerCase();

lib/services/jellyfin_client/parts/playback.dart

@@ -150,7 +150,7 @@ mixin _JellyfinPlaybackMethods on MediaServerCacheMixin {
     );
     var effectiveSourceId = bundle.selectedSourceId;
     var effectiveContainer = bundle.container;
-    var externalSubtitles = _buildExternalSubtitles(metadata.id, effectiveSourceId, mediaInfo);
+    var includeExternalSubtitleDelivery = false;
 
     String? videoUrl;
     String? playSessionId;
@@ -187,7 +187,6 @@ mixin _JellyfinPlaybackMethods on MediaServerCacheMixin {
             chapters: bundle.chapters,
             trickplay: bundle.trickplay,
           );
-          externalSubtitles = _buildExternalSubtitles(metadata.id, effectiveSourceId, mediaInfo);
         }
 
         final negotiatedPlaySessionId = negotiation['PlaySessionId'];
@@ -208,6 +207,7 @@ mixin _JellyfinPlaybackMethods on MediaServerCacheMixin {
           videoUrl = _withApiKey(transcodingUrl);
           playMethod = 'Transcode';
           isTranscoding = true;
+          includeExternalSubtitleDelivery = true;
         } else if (directStreamUrl is String && directStreamUrl.isNotEmpty) {
           capturePlaySessionId(directStreamUrl);
           videoUrl = _withApiKey(directStreamUrl);
@@ -224,6 +224,12 @@ mixin _JellyfinPlaybackMethods on MediaServerCacheMixin {
 
     final effectiveAudioStreamId = _resolveJellyfinAudioStreamId(requestedAudioStreamId, mediaInfo);
     mediaInfo = _withSelectedJellyfinAudioStream(mediaInfo, effectiveAudioStreamId);
+    final externalSubtitles = _buildExternalSubtitles(
+      metadata.id,
+      effectiveSourceId,
+      mediaInfo,
+      includeExternalDelivery: includeExternalSubtitleDelivery,
+    );
     final pinnedSourceId = bundle.pinnedSourceIdForItem(metadata.id);
     videoUrl ??= buildDirectStreamUrl(metadata.id, container: effectiveContainer, mediaSourceId: pinnedSourceId);
 
@@ -316,10 +322,15 @@ mixin _JellyfinPlaybackMethods on MediaServerCacheMixin {
     return path.startsWith('/') ? path : '/$path';
   }
 
-  List<SubtitleTrack> _buildExternalSubtitles(String itemId, String? mediaSourceId, MediaSourceInfo mediaInfo) {
+  List<SubtitleTrack> _buildExternalSubtitles(
+    String itemId,
+    String? mediaSourceId,
+    MediaSourceInfo mediaInfo, {
+    bool includeExternalDelivery = false,
+  }) {
     final externalSubtitles = <SubtitleTrack>[];
     for (final track in mediaInfo.subtitleTracks) {
-      if (!track.isExternal) continue;
+      if (!track.isExternalFile && !(includeExternalDelivery && track.usesExternalDelivery)) continue;
       final path = track.key ?? _jellyfinSubtitleFallbackPath(itemId, mediaSourceId, track);
       if (path == null) continue;
       // Jellyfin's subtitle URL is a path relative to baseUrl; build the

lib/services/jellyfin_mappers.dart

@@ -424,7 +424,7 @@ class JellyfinMappers {
           channels: f.channels,
           frameRate: f.frameRate,
           forced: f.isForced,
-          sidecarPath: f.isExternal ? f.deliveryUrl : null,
+          sidecarPath: f.isExternalFile ? f.deliveryUrl : null,
         ),
       );
     }

lib/services/jellyfin_media_info_mapper.dart

@@ -169,6 +169,7 @@ List<MediaSubtitleTrack> _withDefaultSubtitleSelection(List<MediaSubtitleTrack>
         forced: track.forced,
         key: track.key,
         external: track.external,
+        usesExternalDelivery: track.usesExternalDelivery,
       ),
   ];
 }