The 4K version of Blu-ray, which supports content at 3840x2160 resolution using double-layer 66GB discs. In late 2015, players emerged that also support DVDs and regular Blu-ray. However, there is little original 4K content as most movies were shot in 2K resolution and upscaled to the Ultra HD 4K format. To gain the benefit of Ultra HD Blu-ray, the HDMI ports on A/V receivers must be at Version 2.0a, which support high dynamic range (HDR) and the wide color gamut (WCG) of 4K Ultra HD. See
Blu-ray,
4K TV and
HDMI versions.