Tosca, BBC2 Live stream, Saturday - How?

[Clive]

Hello,

You helped me capture the live R3 audio broadcast of Tosca a couple of 
months ago and now the BBC is broadcasting the video of the same on BBC2 
on Saturday afternoon. As it is music and the ROH, I do not know if it 
will be available from iplayer later so would like to capture is live 
just in case. Can I do this ... or, how can I do this?

I use Terminal on Linux or the command prompt on Windows. I have viewed 
source in Chrome with live BBC2 playing but can't see anything that 
looks like a streaming url in a similar format to that used on the R3 
capture.

Thank you for your (continued) assistance.

Clive