Probably would be better carefully tap into the signal lines to the LCD panel, and record and decode that data to then make a video. However if we assume that even the cable going to the panel is encrypted and the board on the panel is decrypting it. (although I have never messed with a panel like that). However it still has to got to drive the rows and columns of the display, so then data to column and row drivers is still in the open.
If we were to even assume the Column/Row drivers chips only accepted encrypted data they still have the individual traces coming out of them. The pitch of the traces is super tiny, but still possible to tap, but would be a massive pain, but still do able.
Although you can get devices that strip the encryption from an HDMI signal these days so it's kinda moot. So it's not exactly something anyone would need to do these days.
If we were to even assume the Column/Row drivers chips only accepted encrypted data they still have the individual traces coming out of them. The pitch of the traces is super tiny, but still possible to tap, but would be a massive pain, but still do able.
Although you can get devices that strip the encryption from an HDMI signal these days so it's kinda moot. So it's not exactly something anyone would need to do these days.