[phh]

"HDR" contains multiple components: - Electro-Optical Transfer Function. That's the famous "gamma" of the display which is no longer a gamma - color space (which real-life color does RGB = 100%, 0%, 0% match) - Absolute brightness. There are metadata in the video files that say that RGB=100%, 100%, 100% mean 2000cd/m2 (and gives the average frame brightness like 10%, which helps scales for displays not capable of 2000cd/m2 everywhere) - Increased bit depth

Display-P3 is only the color space (and maybe the EOTF). This video uses the "absolute brightness" feature of HDR to increase brightness.