Streaming ... But No Download
In addition, you are infringing by copying and displaying the clips, regardless of whether people can download the material. (By the way, modern software products make it possible to capture any streaming video.) You may be able to successfully claim fair use -- courts have considered clips of 15 seconds and 41 seconds to be fair use (scroll down this page to the audiovisual cases) and in addition, your use seems transformative. By the way, there is also a code of "best practices" for creating online videos and you may want to take a look at that, as well as the Yes, You Can! manifesto.