Brackets Help

I have a bunch of music MP3 files in a folder. Some of them have their title tag set as, for example:

Back Up [Feat. xx] [Album Version]

I want to create an action that will define, if title tag has two pairs of square brackets "[]", the first pair should be replaced with round ones "()"

Back Up (Feat. xx) [Album Version]

Is it possible to create such action (expression) ?

I did find a similar post that does the reverse of what I want so maybe it could be adopted to my needs.

Brackets HELP

Thanks!

Original from the thread:
$regexp(%TITLE%,'^([^(]+?)\s(([^(]+?))\s(([^(]+?))$','$1 ($2) [$3]')
My suggestion:
$regexp(%TITLE%,'^([^(]+?)\s[([^(]+?)]\s[([^(]+?)]$','$1 ($2) [$3]')

This does not work, it gives me a regex error:-

REGEXP ERROR: Regular expression

Found a closing ) with no corresponding openening parenthesis. The error occurred while parsing the regular expression fragment: ')s[([^(]+?>>>HERE>>>)]s[([^(]+'.

Copy & Paste error?

I just tested it with the Tag-Tag-Converter:
$regexp('Back Up [Feat. xx] [Album Version]','^([^(]+?)\s[([^(]+?)]\s[([^(]+?)]$','$1 ($2) [$3]')

and it leads to
Back Up (Feat. xx) [Album Version]

I see the problem, the forum or a human has lost the double backslashes.

Your code does work with double backslashes.

1=$regexp(%TITLE%,'^([^(]+?)\\s\\[([^(]+?)\\]\\s\\[([^(]+?)\\]$','$1 ($2) [$3]')

Thanks!

I have been editing the .mta action file directly with a text editor, double slashes work.