changing video picture ratio?

Archived from groups: rec.video.desktop (More info?)

I recently recorded video off Sky satellite TV while I was away.
When I played it back I got a letter box effect as there were wide
black lines on the top and bottom of the picture.
It was recorded on a DVD video recorder. I tried to copy it on to a
DVD disc and play it back on my DVD player with a setting of 16:9 but
it made no difference to the letterbox type of picture.

If there some software I can use on my computer for converting the
picture to a different ratio (such as stretching the picture
vertically) and re-saving the video to a DVD disc?

Regards Brian