I am learning English and I want to record this stream.
It's using Flash Player and in addition include PDF doc.
Thanks for your interest.
Video Production Stack Exchange is a question and answer site for engineers, producers, editors, and enthusiasts spanning the fields of video, and media creation. It only takes a minute to sign up.Sign up to join this community
Use a browser plugin such as https://addons.mozilla.org/en-US/firefox/addon/video-downloadhelper/.
When you go to the page after installing, an icon will alert you to downloadable media and provide you different formats if they are available.
I don't know about legal part of downloading video from youtube... But you can do it without installation of any side softwere:
Write "ss" in the link before "youtube.com" part. So, if it was