Vegas Adds Letterbox When Rendering As .MOV But Not When Rendering As .WMV or AVI

[johnjm22]

The original video is a 1280x720 .MOV file and IS NOT letterboxed. My Vegas session is set at 1280x720, and I'm rendering as 1280x720. If I check off the "stretch video to fill output frame size (do not letterbox)" option in the render as menu, the finished render is still letterboxed. If I DO NOT check off the option, it's letterboxed as well; there's no difference.

If I render as a WMV, it's comes out perfectly; no letterboxing. (This is WITHOUT the aforementioned option being checked off). The problem is, I need this to be a .MOV file or an .AVI file, not a WMV file.

Can someone help me out? I just want my rendered video to be basically the same as my original video that I'm editing. (1280x720 / .MOV / 8 KBPS (data rate) / 29 fps)

EDIT: I'm using Vegas Pro 9.0e

[Midnight Blue]

The only thing I know of that would do this is if you don't have the correct Pixel aspect ratio set. If your origional footage is 1280x720 and the project settings are 1280x720 and you are rendering at 1280x720 I don't know how you manage to get a letter box on your final output. I tried it and had to change the pixel aspect to less than 1 (square) to do it.