its your answer
http://www.mathworks.com/help/matlab/ref/audioread.html
http://www.mathworks.com/matlabcentral/fileexchange/13852-mp3read-and-mp3write
http://www.mathworks.com/matlabcentral/fileexchange/13852-mp3read-and-mp3write/content/mp3readwrite/html/demo_mp3readwrite.html