The difference is: An actual “4K”, i.e., UltraHD Blu-ray Disc, player, supports actual 4K disc content, and will play “UltraHD Blu-ray Disc” branded discs. A “4K Upscaling” Blu-ray Disc player only supports Blu-ray Discs, but upscales them to 4K for output to your TV. ... It just upscales regular HD to a 4K video format.