You naturally save a video as a 480 by 720 video. But how do you save one as a 1280 x 720 Widescreen video? I don't want black bars, I want the whole shape of the video box fill a widescreen monitor.
Was your video shot in widescreen mode, or 4:3? You see, telling us that your video is 720x480 doesn't help, because that's the same resolution for both 4:3 and widescreen DV footage.
Also, there's no reason to export at 1280x720 (unless your playback device requires it to be as such). If your footage is widescreen DV, then export at 872x480 instead, with pixel aspect ratio 1.000.
Well here is more specfics, say I want to take 4 little different 4:3 videos playing at the same time, and shrink them to make them fit in the same screen, and that is when I want to make the whole screen 720x480. I just want the shape of the video to be that rectangle shap, and no black bars included in the vid. Just like when you view movie trailers off of quick time in it's quicktime player.
You need to tell us the resolution AND aspect ratio of your 4 clips, and how you want to export exactly (e.g. 720x480 and WITH WHAT aspect ratio). You are forgetting the aspect ratio aspect in your comments, which is something that's needed to give you an informed solution.
Okay, I'm wanting to take say, two different wmv 720X480 videos and have them sitting side by side to each other, piece them together into a 1280 X 720 video that will not have black bars showing when you play it. You know when you save a movie trailer off of quicktime, and the quicktime file is always playing in it's rectangular shape and no black bars? I want my videos to turn into something like that.
This assumes that your 720x480 videos have aspect ratio 1.000. If they are widescreen videos themeslves, then you won't be able to avoid letterboxing -- unless you crop them or squeeze them.