This repo has two scripts: one for starting an ffmpeg instance that runs in the background capturing the tty display and internal mic for audio; and another for stopping this process since it's running in the background.
To start streaming, type the following in a bash prompt:
$ ttygrab
Enter file name (including .mkv):
testing.mkv
Because this requires root privileges to grab directly from framebuffer devices (/dev/fb0), sudo will ask for your password.
To stop recording, use:
$ endstream
This will issue a killall command for ffmpeg, again requiring root privileges.
The video will be owned by root and write-protected. You'll need to run a chown/chmod accordingly to modify video permissions if needed.