I am learning english and I want record this stream.It's using flash player and in addition include PDF doc. thanks for your interest
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
- https: //www.youtube.com/watch?v=Bpc2jmNpL78
- https: //www.ssyoutube.com/watch?v=Bpc2jmNpL78