TV cable and socket question

[Tod]

Hi All,

I have a TV socket in my living room but I want to place the TV in my bedroom. I would need 10-20 metres of cable to extend the socket to my bedroom.
The cable is normally round and I would have problem closing the bedroom door. Are there flat TV cables out there? Where would I buy them? I assume that the normal round ones would be available in places like Fust and Coop but what about the flat ones?

Any special German name I should be aware of? Would appreciate your help.
Saint Google did not provide many answers for "flat TV cable".

Thanks