What is 4K Ultra HD resolution?

Here are few elements that make up 4K Ultra HD:

  • More frames per second (fps)
  • Higher pixel resolution
  • Greater color depth
  • HDR (High Dynamic Range)

Note that some 4K devices may not support all the above ingredients and the capability of their support may also vary.

Whether you plan on purchasing a Roku® streaming player or Roku TV that supports 4K or 4K HDR, it is important to understand the requirements for streaming 4K or the requirements for streaming 4K HDR.

What are frames per second (fps)?

The fps is also important for the User Interface, or UI. In general, the frame rate needed to avoid jerky motion during video playback and when using the UI is about 60fps. Images at 60 fps are smoother with more details. The more fps, the sharper the content.

What is pixel resolution?

Your TV is made up of super tiny dots called pixels. These pixels line up like a grid to create images on your TV screen. The more pixels there are, the sharper and more realistic images look. When we can see individual pixels, images look blocky and less lifelike, so we usually prefer displays with a higher resolution, and 4K is very high resolution indeed. That is why it is sometimes known as "4K Ultra High Definition".

The name 4K comes from the fact that there are roughly four thousand pixels on the horizontal side, which gives 4K four times as high a resolution as 1080p, which is what we normally mean today when we describe a screen as "Full HD".

What is color depth?

“Color depth” refers to the total number of possible colors that can be displayed on a screen. The higher the color depth, the more shades of every color that can be displayed. This results in a richer, more realistic image, coming closer to what the human eye can perceive in the real world.

Full HD (1080p) delivers 8-bit color depth, but 4K Ultra HD makes up to 10-bit color depth possible (dependent on your TV).

What is HDR?

For more information, read the detailed support article about HDR.

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