Terje-
There must be a reason you chose to render to a frame size of 736×416. Could you explain what that is? A specific device perhaps? File had to fit in a pre-designed web page? Other?
Also, what is the Nero encode’s frame size and bitrate? Is it the same as what you told Vegas to render with MC/AVC? How about the profile, framerate, field order… are those also the identical, or very close?