What is this and how do I fix it?

paul cliff

The blocky effect, this is Gotham on Netflix but happens on everything. 65” 4K Sony

next010

Macroblocking from the looks of it.

Typically the result of video compression though that is not the only cause, I would imagine Netflix video encodes try to minimize that so it might be your TV settings, like contrast/brightness is set too high or some other contrast post processing effect is highlighting the artifacts in the compressed video stream.

noiseboy72

That level of solarisation and blocking suggests that the brightness and colour settings on the TV are way too hot.

Download a set of test charts - these: AVS HD 709 - Blu-ray & MP4 Calibration - AVS Forum | Home Theater Discussions And Reviews are good. Follow the instructions to set up the backlight,  brightness and contrast correctly. You can then set up the colour to give natural skin tones and adjust the gamma to give good contrast without highlights either being blown out or things disappearing into the black too much. Use the Movie setting as a basis, as this will be pretty close in terms of colour management, as you need a meter to do anything much in terms of grey scale and gamma.

You should end up with a slightly dimmer image, but with better colour matching and less artifacts.  

Worth checking your internet feed if this is worse on streamed movies, as it may be defaulting to a lower quality setting.