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4K 対 UHD



The difference between 4K and UHD lies in the number of pixels per horizontal scan line. Specifically, the spatial resolutions are:

4K: 4096 (h) x 2160 (v)

UHD: 3840 (h) x 2160 (v)

You will note a few things about these resolutions. 4K creates an image width to height ratio of approximately 17:9 and is intended for cinematic experiences. UHD is 16:9 and is intended for television viewing. UHD is double the number of pixels in both width and height of the popular 1080i/p HDTV resolutions. This last attribute makes scaling and displaying UHD images on HDTV sets and monitors are rather straightforward process. It also facilitates the display of HDTV signals onto a UHD screen without geometric distortion.




The transport of 4K/UHD uncompressed baseband signals can be accomplished in a number of different ways based on today’s technology. On the HDMI interface, the new HDMI v2.0 specification can support both 4K and UHD resolutions up to 60 fps. The HDMI v1.4 specification only supports 4K/UHD up to 30 fps. Keep this in mind when purchasing that new UltraHD television or monitor.

Currently, the SDI interface can be used to support 4K/UHD up to 30 fps by using either two 3 Gbps signals or one 6 Gbps signal. 4K/UHD up to 60 fps can be supported using four 3 Gbps signals or two 6 Gbps signals. The goal, of course, is to achieve a cost-effective single 12 Gbps link to support 4K/UHD up to 60 fps that can be transported over copper or fiber.