With a lot of these techniques, you can't just start with better source material. The frames have to be resized before going through the neural net, so that the

With a lot of these techniques, you can't just start with better source material. The frames have to be resized before going through the neural net, so that they fit its expectations. So if you want to start from a 4k source, you have to train your network on 4k data, and that becomes a ludicrously expensive exercise quite quickly.