What do you mean by "using?"
If you are just watching the videos, probably not, because you are not making a "copy" of the video (although your computer does arguably cache at least a partial copy while you are viewing, this is unlikely to be considered a "copy" for the purpose of copyright infringement).
If you are making a copy of the video, or hosting it on your own site, or something like that, then yeah, you could be liable for copyright infringement.