[andrewstuart2]

My quick and dirty solution. Worked at least for my (Linux) laptop.

1. Chrome > Dev tools > Network tab > Search "webm" (everybody uses html5 video, right?) > Right click a request, "copy as CURL".

2. Insert into CLI, remove &range=- parameter, and redirect output to some file (or use -o curl option)

3. mplayer somefile.webm -rootwin -vf scale=1920:1080 (or whatever)

I'm sure there's a better/easier way, but it's a start.