For now, always encode mp4

MediaBrowser.Api/HttpHandlers/VideoHandler.cs

@@ -28,7 +28,7 @@ namespace MediaBrowser.Api.HttpHandlers
 
             // For now we won't allow these to pass through.
             // Later we'll add some intelligence to allow it when possible
-            if (currentFormat.Equals("mkv", StringComparison.OrdinalIgnoreCase) || currentFormat.Equals("m4v", StringComparison.OrdinalIgnoreCase))
+            if (currentFormat.Equals("mp4", StringComparison.OrdinalIgnoreCase) || currentFormat.Equals("mkv", StringComparison.OrdinalIgnoreCase) || currentFormat.Equals("m4v", StringComparison.OrdinalIgnoreCase))
             {
                 return true;
             }