I'd like to use filebot to rename my tv-recordings.

Usually I add stl 1x8 to the title, for the renamer to know what episode it is.

So the filename would be something like
20170908 1131 - SomeBelgianChannel - Firefly.ts

I'd change that into
20170908 1131 - SomeBelgianChannel - Firefly 1x1.ts ...