I've recently had to buy a new TV as my old plasma screen broke down and couldn't be repaired. I'm not that savvy when it comes to AV matters so would appreciate some advice. My new TV is 4K. The installers did not connect up my existing DVD player because the connectors were wrong, but they did connect my existing Sky box. Am I right in thinking that I need to upgrade to a 4K DVD player, and also possibly a 4K Sky box, in order to get decent picture quality?