Yes, this ONLY works on a device with 4.4. Have tried it with my Nexus 7, but I get some odd decoder error/warning that I haven’t dug deeper into yet. It does however work.
So, how do you do it?
FIrst off: you can’t unless you’ve got root start it on the device itself, but you have to do it from a computer.
This page gives you all the commands needed for it. It’s not a pretty solution but it kinda works.
Simple start with (in a command line)
which opens the adb shell on your device, continue with
screenrecord --time-limit 20 /sdcard/demo.mp4
Which gives you a 20 second recording to demo.mp4, or leave out the time limiter and simply let it record the 180 seconds that are maximum what it can do or press CTRL-C to stop it. That’s pretty much it.
Exit the adb shell
Or you can combine both the ADB SHELL and SCREENRECORD command
adb shell screenrecord /sdcard/demo.mp4
And pull the video you recorded off your device with
adb pull /sdcard/demo.mp4