The video-dynamic-range CSS media feature can be used to test the combination of brightness, contrast ratio, and color depth that are supported by the video plane of the user agent and the output device.
Some user agents, including many TVs, render video and graphics in two separate planes (bi-plane) with distinct screen characteristics. The video-dynamic-range feature is used to test the characteristics in the video plane.
Syntax
The video-dynamic-range feature is specified as a keyword value chosen from the list below.
standard-
This value matches any visual device and excludes devices lacking visual capabilities. A user agent or an output device that matches
highwill also match thestandardvalue. high-
This value matches user agents and output devices that support high peak brightness, high contrast ratio, and color depth greater than 24 bit or 8 bit per color component of RGB. Peak brightness refers to how bright the brightest point a light-emitting device, such as an LCD screen, can produce. In the case of a light-reflective device, such as paper or e-ink, peak brightness refers to the point that at least absorbs light. Contrast ratio refers to the ratio of the luminance of the brightest color to that of the darkest color that the system is capable of producing. Currently, there is no precise way to measure peak brightness and contrast ratio, and the determination of what counts as high peak brightness and high contrast ratio depends on the user agent.