Python + openCV + video

The purpose here is to play video in rPi using python + openCv. However, the avi file i call do not load as expected. I stripped off all the other code pieces, and focus on the loading to cheack what is wrong: and it printed False, which means it cant read my video format a quick google brought me here. I will need to download mplayer¬†first and use the memcoder in it to convert the format. and now, it runs perfectly The complete code to play video: