The best way to know what you are downloading is to use Bitzi, this thread will explain how to use it...
http://www.gnutellaforums.com/showthread.php?t=37676
Generally you will know if the movie is full length by the size of the file...
You can also preveiw your downloads, but wait until they have at least 10% done..
The codes at the side are the formats that the movie is in...