Applescript (PDF to iTunes): How to extract and/or write metadata with special characters? Help please :-)
You can use perl to convert escaped unicode character from ASCII text :

tell application "iTunes"
    set sel to the selection
    if sel is {} then display dialog "Please select something" buttons {"Cancel"}
    set tc to count sel
    repeat with i from 1 to tc
        tell (get item i of sel)
            set loc to location
            set authorfield to my getAuthors(loc)
            if authorfield is not "" then set artist to authorfield &amp; "-"
        end tell
    end repeat
end tell

on getAuthors(f)
    do shell script "mdls -name kMDItemAuthors  " &amp; (quoted form of POSIX path of f) &amp; " | /usr/bin/perl -ne 'if (m/^ /) {s/^ +[\"]?|\"$//g;s/\\\\u([[:xdigit:]]{1,4})/chr(eval(\"0x$1\"))/egi;print}' "
end getAuthors


Or python :

do shell script "export PYTHONIOENCODING=UTF-8; /usr/bin/python -c 'import sys; print (sys.argv[1].replace(\"\\U\",\"\\u\").decode(\"unicode-escape\"))' \"$(mdls -name kMDItemAuthors  " &amp; (quoted form of POSIX path of f) &amp; " |  sed -nE 's/\"$//;s/^ +[\"]?//p')\""