#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?<=watch\?v=|/videos/|/shorts/|/live/|embed\/|youtu.be\/|\/v\/|\/e\/|watch\?v%3D|watch\?feature=player_embedded&v=|%2Fvideos%2F|embed%2F|youtu.be%2F|%2Fv%2F)[^#\&\?\n]*"
Local $sString = "https://www.youtube.com/live/jfKfPfyJRdk?si=w62kL85ADoUnGlOQ"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYFULLMATCH)
; Present the entire match result
_ArrayDisplay($aArray, "Result")
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