When you play a 4K video on a 1080p screen, the video will be downscaled to match the resolution of the screen. This means that the 4K video will be compressed into a 1080p resolution, which can affect the overall quality of the video. The picture may look slightly blurry or soft compared to native full HD content. The process of downsampling reduces the native 4K UHD video to the TV's 1080p Full HD resolution. Each 4K pixel gets mapped to a block of 4 pixels when condensed into 1080p. However, even though the video is downscaled, it will still appear as a higher quality than video captured using 1080p cameras.