HDR Explained

Shining light on the most significant recent development in home video

- Kris Deering

MY EXPERIENCE covering home video extends back to the early days of DVD. But of all the new technologies and formats I’ve covered in that time, none has generated as much confusion as high dynamic range (HDR). In this article, I will attempt to demystify the subject of HDR, a technology that I find to be the most significant development to hit home video in years.

LIFELIKE DEFINED

Dynamic range in audio or video describes the difference between the lowest and the highest levels of information available in a signal. So, to describe something as having a “high dynamic range” is to state that it offers a wider dynamic range than was previously available. What are the implications for the viewing experience? In simplest terms, it means there is an increase in the number of brightness levels the display is capable of reproducing. This results in a more “true to life” image: no more muted headlights on dark highways, or dim stars against the black of space. But it doesn’t stop there.

While HDR photography is well established, HDR video is relatively new. Much of it results from work done by Dolby Laboratories, which first launched HDR in theaters with Dolby Cinema and later brought it to Ultra HD Blu-ray and streaming via Dolby Vision. The most common HDR format is HDR10, a bare-bones version derived from the work the company did with Dolby Vision that was provided to the industry royalty-free. Additional HDR formats include Hybrid Log Gamma (HLG), Technicolor’s Advanced HDR, and HDR10+, but all of these are either in early development or have limited available content. I’ll touch on them more in a bit.

LIGHT, BRIGHT: SDR VS. HDR