Yep pretty much it shreds the image and builds a new valid frame from it, some quite often do some separate things to the chroma and luminescence carriers with drones really depends because some times if you are transmitting multiple black and white images you can cheat an multiplex them together and basically instead of extrapolating the correct color from each field you can extrapolate 2 different images. 
Because it&#x27;s analogue data you always getting an image regardless if you have the correct key or not, and because of the limitations of the encryption&#x2F;scrambling it self once you get a key which is close enough you being to reconstruct various parts of the correct image even in a form of artifacts so things like edges become apparent very quickly.