update interlaced detection

MediaBrowser.MediaEncoding/Encoder/MediaEncoder.cs

@@ -292,11 +292,11 @@ namespace MediaBrowser.MediaEncoding.Encoder
                 return false;
             }
 
-            var formats = (video.Container ?? string.Empty).Split(',').ToList();
-
             // If the video codec is not some form of mpeg, then take a shortcut and limit this to containers that are likely to have interlaced content
             if ((videoStream.Codec ?? string.Empty).IndexOf("mpeg", StringComparison.OrdinalIgnoreCase) == -1)
             {
+                var formats = (video.Container ?? string.Empty).Split(',').ToList();
+
                 if (!formats.Contains("vob", StringComparer.OrdinalIgnoreCase) &&
                     !formats.Contains("m2ts", StringComparer.OrdinalIgnoreCase) &&
                     !formats.Contains("ts", StringComparer.OrdinalIgnoreCase) &&