You might be seeing bad files, especially if you're searching for a really new/popular video. There's a lot of junk around! Check the file before download with Bitzi. Right click the file > advanced > look up file with Bitzi. If other users have rated the file, you'll get some idea of content & quality. If a video file has heaps of sources but no Bitzi rating, chances are that it's a fake or junk.

There's info about how to use Bitzi within the thread below
Fake files showing up in search results

And some good info & tips here as well.
How to find music (tips for video also)