I know that a piece of software called "KRAD
RADIO" can do this kind of
stuff. Though it's still in a stage of development where things change
often and redically, version tagged as "13" in github is quite stable:
https://github.com/krad-radio/krad_radio/archive/Version_13.tar.gz
I had problems with compiling that tarball.
./waf configured barfed:
So I used git tags:
After you build from source, you basically fire up a
"station", set the
(output) resolution and framerate, add the X11 capture for the live
image, add a jack input for the audio and set up the
"record-to-file"-part, specifying the codecs (WebM by default).
All commands needed are documented here:
https://wiki.mozilla.org/Krad_Radio/Commands
and some example "sessions" can be found here:
https://wiki.mozilla.org/Krad_Radio/Snippets
Live streaming the output is also possible.
If you have any questions, you can visit the devs in IRC at
irc://orc.mozilla.org/#kradradio or ask me:)
Best regards,
Jannis