How to change display aspect ratio without recoding?

[Nick Less]

I have a clip made in Divx 6.4.0 and it's displayed as a 4:3 (or something close to it) but instead it should be 16:9. MPEG Modifier doesn't accept the file and reports error: This is not a valid MPEG-4 video (startcode not found at beginning of the frame).

GSpot reports the following aspect ratios (http://img295.imageshack.us/img295/436/gspotxs0.jpg).

Now, i know i can't change the aspect ratio itself without recoding, but is there another tool like MPEGModifier that would allow me to change display aspect ratio without recoding?

[CWR03]

If you're only playing it back on a PC, you can resize it with ffdshow, or you can create an .avs script that will allow it to play back at the proper aspect with no changes made to the original file in either case.