Why is 700mb file converting to a 3mb AMV file?

So I download (via torrent) a couple of 700mb movies.

I upload them to my (trial version) AMV Convertor Studio and put C:/My Videos as the location.

It converts them (in a couple of seconds) yet when I go into the My Videos file the two movies are there as 3mb & 4mb .amv files respectively.

And when I move them to my generic (ebuyer) MP4 player they are about 20 seconds long.

What’s the problem / solution??

Cheers

My best guess would be corruption in the data stream. It probably aborted when it encountered stuff it couldn’t read/decode/convert. Don’t know if there’s a solution besides re-encoding the whole video.