Emulator video recording with correct aspect ratio

[Kweepa]

Hi,
I'm planning to make a promo video for Vic Doom, and I wanted to make sure the aspect ratio was correct.
I haven't found a good way to make this happen.
I have a fraps license, but if I use VICE (which I think I need, to get d64 support) either it's stretched or it's stretched and clipped.
Is there a good free video editor that allows for readjustment of the aspect ratio?

[tokra]

I think AVIDEMUX can do what you want:

http://avidemux.org/

Load a video, select a codec under "Video" - then goto Filters and select "Transform"-then double-click on "Resize".