======Maintainer's notes======
=====Video=====
Grab video (994x746) with 30 pixel top-offset.
ffmpeg -r 24 -f x11grab -s 994x746 -i :0.0+0,30 -threads 0 -vcodec libx264 /tmp/out.mkv
The 994x746 video size matches the minimum window size of Ardour, and the 30 pixel verticla offste matches my toolbar at the top of the screen. In other words, this command records the entire Ardour window when positioned in the upper left corner of my screen and sized to the minimal size allowed by Ardour.
=====Audio=====
jack_rec -f /tmp/showcase.wav 'ardour:master/audio_out 1' 'ardour:master/audio_out 2' -b 16 -d100000
NOTE: Without the -d option it seems the recording is terminated immediately...\\
NOTE: Ardour and jackd must be started before this command is activated.
\\
Here is another version that also records from the first channel of the soundcard (as a third channel!!!):
jack_rec -f /tmp/showcase.wav 'ardour:master/audio_out 1' 'ardour:master/audio_out 2' 'system:capture_1' -b 16 -d100000
Since this will result in a three channel wav this might not be what you want.
Start the initial command instead and connect the system:capture_1 channel to the jack_rec using the qjackctl "Connections" window. This will make it possible to mix the channels instead.
=====Transcode=====
Transcode said video to ogg format (html5 video tag compatible):
ffmpeg2theora /tmp/out.mkv