How to decode mp3 file

how get the artist of a mp3 file using lisp

(let ((in (open "test.mp3" :direction 
        :input 
        :element-type '(unsigned-byte 8))))
 (when in
   (loop for line =  (read-byte 'utf-8 in)

      开发者_如何转开发while line do (format t "~a" line ))
    (close in)))

A complete ID3 (MP3 tag) parser is described in the book Practical Common Lisp, chapter 25.