Changing a part of the track name

I'd like to change just a part of the track name:

[Original Mix] -> [original mix]

  1. Before this action, I will replace the () parentheses with [] parentheses.
  2. Anythings within [] parentheses should be replaced by lowercase text.

I thought I saw kind of script programming withing MP3TagEditor, though I cannot find any information about how to do this now.

ANY idea is highly appreciated.
Thank you.

create an action of the type "replace with regular expression"
as regular expression enter:

(.)([.])(.*)

as replace string enter

$1$lower($2)$3

(the ususal safety precautions apply: try it first to see if it fits then use it on the tracks that have best been selected with a filter)

Thank you for very fast response.
Your tip is perfect.