strip invalid xml chars

MediaBrowser.Api/Playback/StreamState.cs

@@ -80,7 +80,7 @@ namespace MediaBrowser.Api.Playback
                             return 6;
                         }
 
-                        return 10;
+                        return 6;
                     }
 
                     if (IsSegmentedLiveStream)

MediaBrowser.XbmcMetadata/Savers/BaseNfoSaver.cs

@@ -16,9 +16,10 @@ using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Text;
+using System.Text.RegularExpressions;
 using System.Threading;
 using System.Xml;
-
+using MediaBrowser.Controller.Extensions;
 using MediaBrowser.Model.Extensions;
 using MediaBrowser.Model.IO;
 using MediaBrowser.Model.Xml;
@@ -353,7 +354,8 @@ namespace MediaBrowser.XbmcMetadata.Savers
 
                 if (!string.IsNullOrEmpty(stream.Language))
                 {
-                    writer.WriteElementString("language", stream.Language);
+                    // https://emby.media/community/index.php?/topic/49071-nfo-not-generated-on-actualize-or-rescan-or-identify
+                    writer.WriteElementString("language", RemoveInvalidXMLChars(stream.Language));
                 }
 
                 var scanType = stream.IsInterlaced ? "interlaced" : "progressive";
@@ -422,6 +424,19 @@ namespace MediaBrowser.XbmcMetadata.Savers
             writer.WriteEndElement();
         }
 
+        // filters control characters but allows only properly-formed surrogate sequences
+        private static Regex _invalidXMLChars = new Regex(
+            @"(?<![\uD800-\uDBFF])[\uDC00-\uDFFF]|[\uD800-\uDBFF](?![\uDC00-\uDFFF])|[\x00-\x08\x0B\x0C\x0E-\x1F\x7F-\x9F\uFEFF\uFFFE\uFFFF]");
+
+        /// <summary>
+        /// removes any unusual unicode characters that can't be encoded into XML
+        /// </summary>
+        public static string RemoveInvalidXMLChars(string text)
+        {
+            if (string.IsNullOrEmpty(text)) return string.Empty;
+            return _invalidXMLChars.Replace(text, string.Empty);
+        }
+
         public const string DateAddedFormat = "yyyy-MM-dd HH:mm:ss";
 
         /// <summary>