my trouble was an AVI file with a different codec. when i used AVIREAD in matlab, it gave me an error that it wasnt able to find the codedc or the frames are not known.
one option that is FREE:
use FFMPEG im downloading the executable for windows from this URL
ffmpeg is a command line tool, so in order to convert to a raw video to use in maatlab you use this command:
c:/> ffmpeg -i foo.avi -vcodec rawvideo bar.avi
foo.avi is your compressed video file
bar.avi is your new raw video file name that you will use in MATLAB