Yes and No.
It is trivial with any router to see what sites you access and what URL you access. So they more than likely could see the name of the file/video you look at. Being able to actually see the content of the video stream is another matter. Since it is not encrypted it is technically possible but because many of the sites try to prevent you from copying the stream it is not a easy thing to do.
Down load a copy of wireshark and install it on your machine and capture your own traffic. You will see it is not a trivial thing to spy on people