We have different copyright laws in Australia, but I think in America it's called 'creative commons' or something like that.
Basically it means that as long as you're not claiming someone else's work as your own or making money from it it means you're permitted to use it in things like online projects, unless the owner requests that it is removed or has a specific request that it isn't used.
Websites like peekvid and Ebaum'sWorld exploit this thing and CAN actually make money off of it through a bunch of legal loopholes, but it doesn't look like you're doing that so go for your life.
By the way, don't go on Ebaum'sWorld.com, it's evil.
No really.