?4K? resolution is a generic term for display devices or content having horizontal resolution in the order of 4,000 pixels. For consumer electronics products (such as TV and Blu-ray players), 4K resolution means 3840 x 2160 pixels (at a 16:9, or 1.78:1 aspect ratio). Our player not only can support image source of 4K, but also upscale images of lower resolution. After upscaling, the image quality would be much improved. For best image quality, get 4K image source whenever possible.