#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)(.*feat.*?)(\s*\(?feat.*\)\s*)(\.[^\.]+)$"
Local $sString = "Artist - Song (feat. OtherArtist) (feat. OtherArtist).mp4" & @CRLF & _
"Artist - Song (feat. OtherArtist) (Radio Edit) (feat. OtherArtist).mp4"
Local $sSubst = "$1$3"
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm