Naming downloaded videos automatically is tricky. The issue is that all sites stream in different formats and manners. Much of the time the stream Replay Media Catcher records comes from a completely different site than that hosting the video. We use a variety of techniques to try and detect the best name possible for a downloaded/recorded stream - the majority of the time Replay Media Catcher gets it right.
In the cases Replay Media Catcher can't find a good video name, you can rename files directly from within Replay Media Catcher. Just right-click the stream and chooseRename from the menu.
If you wish to send us web site(s) that consistently give gobbly gook file names then please do so - provide as many details as possible.