How Many Seconds From TV Show?

Dear Rich, I would like to ask you how long/how many seconds we can use from movies and, well any video material. I think the answer is like 5 seconds or something. What I mean is that can we mix in with our own material with some material that is copyrighted? I am building a 'TV intro' to be used on my website that is an upcoming Online Business Incubator. I live in Sweden. It would be so great if there were a "five-second rule" or something similar. Alas, any assurance of safety based on the number of seconds borrowed is a myth. The same is true for the so-called "8-bar" and "8-note" rules. The U.S. Congress refuses to quantify the border between permissible borrowing and infringement and the legislators leave the heavy lifting to the judges. In the U.S., the only course is to review the fair use caselaw to see what's been permitted in the past (and why). By the way, as a very general rule, it's not the amount of time taken but the importance of the section taken and the context in how it is used. Also, our usual disclaimers here: our staff doesn't know Swedish copyright law although a cursory look seems to indicate there is no fair use equivalent.