Television has used the same color primaries and gamma for decades. The world of HDR and WCG has brought confusion due to multiple color spaces and gamma functions. In this webinar, IABM’s CTO, Stan Moote, grills SRI Sarnoff’s Norm Hurst on what you need to know on both the production and the technical side.
Before HDR, we considered the peak range of a video signal. We knew that 0 to 100 IRE would be fully reproduced on any display in some relative brightness. Now with HDR10, code values are assigned to absolute brightness values, so displays make a “best effort” approach, often compromising or crushing white highlights. Display brightness is measured in Nits (candela per square meter).
On the production side, we set SDR video levels relative to “peak white”. But HDR provides many more f-stops of dynamic range, so we can now expose for the midtones, like they’ve done in photography for many years, and let peak white go where it may – although not entirely. We still must be concerned about how bright the graphics are. So now we have two kinds of “peak white”: specular and diffuse.
Norm Hurst has been designing test patterns for decades that both help reveal real life issues and aid with setups. Both Norm and Stan are SMPTE Digital Processing Medal Recipients and will assist your learning with questions like: How can I determine brightness limits? And how do I determine that tone map? And what happens when bright colors get clipped? Do the colors shift?