2016-05-22, 23:07
HDR Video Explained
Sunset HDR
HDR video works by mastering content in a way that maximizes peak white luminance to allow for brighter highlights and more texture detail in bright image areas. Colorists have worked with a peak brightness limit of 100 nits for BT.709 HD content for decades. However, current displays are now much brighter than 100 nits and have been so for a long time, so this legacy SDR contrast range is severely restrictive and often leads to clipping at the top of the range and the need to compress high-contrast footage.
HDR enhancement also defines reference white (normal diffuse white) as 100 nits, but avoids clipping the brightest details by leaving room for specular highlight detail up to 10,000 nits. Because most of what we can see was already contained in the SDR range, the Average Picture Level, or APL, of HDR video still remains largely under 100 nits, but the increased range of brightness allows for the creation of scenes with more natural contrast and lighting with realistic brightness peaks for very bright elements like the midday sun or the chrome reflection on a car.
This increase in peak brightness doesn’t just benefit the highlights. Many colors are now able to be brighter and more colorful in HDR, even current BT.709 colors in the SDR range, due to the freedom provided by a much higher peak white limit. Combined with an expanded color gamut, the result can be images with significantly improved color volume and contrast.
Understanding UHDTV Displays with PQ/HLG HDR and WCG
High Dynamic Range (HDR): An Explanation of Dynamic Range, Resolution, Color, and Calibration
TVs Are Only Getting Brighter, but How Much Light Is Enough?
Comparison Photos of HDR and SDR and Information on HDR Mastering
Grading, Mastering, and Delivering HDR
HDR Video & Color Volume
The HDR Ecosystem Tracker (mid-2019)
Sunset HDR
HDR video works by mastering content in a way that maximizes peak white luminance to allow for brighter highlights and more texture detail in bright image areas. Colorists have worked with a peak brightness limit of 100 nits for BT.709 HD content for decades. However, current displays are now much brighter than 100 nits and have been so for a long time, so this legacy SDR contrast range is severely restrictive and often leads to clipping at the top of the range and the need to compress high-contrast footage.
HDR enhancement also defines reference white (normal diffuse white) as 100 nits, but avoids clipping the brightest details by leaving room for specular highlight detail up to 10,000 nits. Because most of what we can see was already contained in the SDR range, the Average Picture Level, or APL, of HDR video still remains largely under 100 nits, but the increased range of brightness allows for the creation of scenes with more natural contrast and lighting with realistic brightness peaks for very bright elements like the midday sun or the chrome reflection on a car.
This increase in peak brightness doesn’t just benefit the highlights. Many colors are now able to be brighter and more colorful in HDR, even current BT.709 colors in the SDR range, due to the freedom provided by a much higher peak white limit. Combined with an expanded color gamut, the result can be images with significantly improved color volume and contrast.
Understanding UHDTV Displays with PQ/HLG HDR and WCG
High Dynamic Range (HDR): An Explanation of Dynamic Range, Resolution, Color, and Calibration
TVs Are Only Getting Brighter, but How Much Light Is Enough?
Comparison Photos of HDR and SDR and Information on HDR Mastering
Grading, Mastering, and Delivering HDR
HDR Video & Color Volume
The HDR Ecosystem Tracker (mid-2019)
