Add option to always burn in subtitles if transcoding is triggered (#12430)

MediaBrowser.Model/MediaInfo/LiveStreamRequest.cs

@@ -13,6 +13,7 @@ namespace MediaBrowser.Model.MediaInfo
         {
             EnableDirectPlay = true;
             EnableDirectStream = true;
+            AlwaysBurnInSubtitleWhenTranscoding = false;
             DirectPlayProtocols = new MediaProtocol[] { MediaProtocol.Http };
         }
 
@@ -40,6 +41,8 @@ namespace MediaBrowser.Model.MediaInfo
 
         public bool EnableDirectStream { get; set; }
 
+        public bool AlwaysBurnInSubtitleWhenTranscoding { get; set; }
+
         public IReadOnlyList<MediaProtocol> DirectPlayProtocols { get; set; }
     }
 }