How to set size in of video clip playback

I am using BSPlayer to play MPEG1 clips within an interactive CD. I invoke BSPlayer using Maestro (an autorun menu program) and give it the commands to play the specific clip and supply it with the proper options.

How can I set the options so that the size of the playback is at a chosen size (ie 720x480). Is this the -res setting? I want the clips to all play over a background window which looks like a frame for the video.

-Thanks,

Marc