Part 1: Understanding HDR

The video industry seems to have a new “hot” technology come along at the same rate as Ben & Jerry’s comes up with new ice cream flavors.  Some prove to be nothing more than a flash in the pan, while others go on to change the industry for many years to come.  We believe that HDR is a game-changer. It offers a significant improvement to the viewing experience, and most importantly the technology is already being widely adopted across various industries.  This is required for any new technology to really take hold, rather than just stumbling along for a few years and then dying (Ahem…Laserdisc, DIVX).

In this first of two articles about HDR (High Dynamic Range), we will first be taking a look at some basics of HDR technology, and how it improves the viewing experience.  The second article will provide a more in-depth look at how HDR works within our industry specifically, as well as how NovaStar is supporting the HDR experience.

HDR photography has been around for years now, and most people are pretty familiar with the result it can achieve, but many make the mistake of thinking that HDR video and HDR photography are the same technology.  HDR photos use a particular type of capture process, combining several shots into a single image that can look more (or less) lifelike than a single image. HDR video, on the other hand, is a display process, allowing a screen to recognize and display content that has been created specifically for HDR.

HDR relies on two major factors to improve the viewing experience: wider dynamic range(contrast ratio) and broader color gamut.

First let’s take a look at how a higher dynamic range can affect the overall image quality. Simply put, dynamic range is the difference between the brightest and darkest parts of the image. Picture a scene where a family is sitting around a bright, glowing campfire, with the surrounding woods being very dark. Peeking out of the woods is a curious black bear.  In the old world of SDR video, the display would have to make a very tough choice at this point.  It could show the darker highlights of this scene, allowing you to pick out the dark bear against the dark woods, but the campfire would seem washed out, losing its bright glow.  Or, the campfire could be shown in all it’s white-hot beauty, but you would never see the bear lurking in the dark background.  HDR, with it’s ability to simultaneously display much brighter whites and much darker blacks, would allow you to easily show off both these important parts of the scene.

The second factor that goes into making HDR video more lifelike is a wider color gamut.  In the past, most displays were only able to display about 17 million colors.  This seems like a lot, but the human eye is able to differentiate between a much greater range of colors than this. HDR is able to push this number up to over 1 billion colors, bringing the video much closer to what we can see with the human eye.  We can look at a simplified example of this to easily understand how important a wider color gamut is.  Imagine an image in which a boy in a light red shirt is holding a dark red lollipop while standing next to a stop sign as a fire truck passes by. If we didn’t have enough shades of red to choose from, we would we would have to make a compromise when deciding which red to use on each object in the image. This would result in the colors not only being slightly different from what we expect to see, but also an overall “washing out” of the image, as there would be a less detailed contrast between the different reds we were seeing.

This all results in an image that is more clear, multidimensional, and “present.” In other words, more lifelike.  HDR video can be hard to describe without seeing it, but once you’ve experienced how much more an HDR video seems to pull you in, it can be hard to go back to enjoying original SDR videos. Hopefully this primer has given everyone a little better understanding how HDR video can change the viewing experience. In the next article of this two-part series, we will go a little more in-depth, taking a look at some technical requirements of HDR video, as well as how NovaStar can help you realize a beautiful HDR solution for your clients.