The easiest thing to do would be to nest those videos in a composition of the size you want.
If you want to see what the region of interest size is you just open the info panel and look. You can't set it numerically but you can see the values.
If you want to crop the videos or even resize them the best option for your workflow would be to:
- Make sure that the 720 X 480 videos are interpreted correctly because they will be non square pixels and either widescreen or 4:3
- Create a new 240 X 480 square pixel comp because this frame size is NEVER non square pixels
- Drag your existing non square pixel 720 DV videos into the new comp and reposition or scale them uniformly to show what you want to show.
That's it. There is not much use for 240 X 480 videos. Are you sure you know what you are doing? That frame size is not supported by h.264 - mp4 compression, which is standard and it's not a standard frame size for any known video format. Make sure you know what you are doing or your video will not be compatible with most devices.
My videos are 720x480, but I don't want to crop them into 240x480, that was a random example.
Thank you for your suggestion, I will try that out!
If the videos are all 720 X 480 they should be non square pixels. if you choose another size you should make it a standard frame size with square pixels.