Fix the preproc filters for dvbsub burn-in (#11034)

Signed-off-by: nyanmisaka <nst799610810@gmail.com>

MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs

@@ -2988,7 +2988,7 @@ namespace MediaBrowser.Controller.MediaEncoding
             {
                 return string.Format(
                     CultureInfo.InvariantCulture,
-                    @"scale=-1:{1}:fast_bilinear,crop,pad=max({0}\,iw):max({1}\,ih):(ow-iw)/2:(oh-ih)/2:black@0,crop={0}:{1}",
+                    @"scale=-1:{1}:fast_bilinear,scale,crop,pad=max({0}\,iw):max({1}\,ih):(ow-iw)/2:(oh-ih)/2:black@0,crop={0}:{1}",
                     outWidth.Value,
                     outHeight.Value);
             }