Separate audio channel from .avi file using simulink

Hi..... I'm working on my graduation project which includes processing videos.. I need to separate the audio channel and video channel from .avi file, as I need to do some processing on them, then reconstruct an .avi file containing the modified channels... I'm working on matlab 2009a, so system object MultimediaFileReader and MultimediaFileWriter are not supported by this version and consequently, I decided to use simulink from multimedia file.. If it's possible, can anyone help me in that? I'll appreciate any help.. thanks