Friday, April 7, 2017

HDR10 - TV setup







Anyone has already thought this through?

1 comment:

Robin Green said...

For the last 20 years we've been living in a Rec.709 world where RGB "just works". You take a picture on your cellphone, move it to your PC, cast it to your TV screen and it just works. That's because all of those devices have been Rec.709 (ok, flat panels use BT1886 to correct for gamma, but that's a small detail). Welcome to the bad old days of 1990's color displays and printing, the days before the HDTV standard. Remember picking your "color intent" before printing a document? They're back!

The problem is that the SDR signal is mapped according to the Rec.709 standard where the maximum intensity of your (1,1,1) pixel is 100 nits. But almost no TV or monitor you use today follows that convention, they on average use 300-nits for a (1,1,1) pixel and further "vividness" controls rotate the RGB colors out of the rec.709 colorspace into something more saturated. You are used to over-sugared content.

The Rec.2100 standard was designed to convert SDR signals to Rec.709 values, so you have to add back the sugar you are used to. Scale your SDR content to 300-nits and rotate your Rec.709 colors into Rec.2100 colorspace before encoding it to PQ for output - that's the basic transform that will solve the "too dim" or "too unsaturated" problems.

After that you can start to tame overbright pixels or start generating Wide Color Gamut values using WCG content, filmic curves and all the bells and whistles.