DVD screencaps?

Hi, I was wondering if any one knows of a good automatic screen cap program for DVDs? I'm having problems with KMPlayer, which I usually use for screen caps, it won't open my DVDs, and my computer freezes every time I try. If anyone has any other programs they use where you can set the frame rate, I'd love to hear about it! I also checked through the tags and didn't find anything about this! Thanks in advance!