HDR Video: Next Year’s Buzzword?

HDR video. High-density rendering? Nope. Happy Days Radio?Nope again. It’s high dynamic range video,and while it’s not a buzzword yet, it will be in the next couple of years. Whatis HDR video, and why will it be more important?

What is HDR?

If you are a photographer, you may be familiar with HDRphotography. In still photography, you take (usually) three exposures of animage: one correctly exposed, one slightly underexposed (too dark), and oneoverexposed (too light), but not by too much. Then the three images arecombined with special software to get the best highlights (brightest) and viewsof the deep shadows (darkest) in an image. Since video moves along at 24 or 30(or more) frames per second, it gets more complex. At 30 frames per second,you’d need 90 frames combined into 30 frames every second. That’s a lot ofprocessing. What combining the frames does is allow you to shoot a scene, say,from the inside of a fairly dark room to the outside. Normally, either you’dhave the interior really dark and the outside exposed properly, or you’d havethe inside looking good and the outside all smashed out. HDR is the solution.

What is HDR video?

HDR video all starts with dynamic range. High dynamic rangeis really an optical illusion. But it’s a good optical illusion. It fools theviewer into thinking the video they’re watching is more lifelike by a hugemargin over today’s video displays.

Your eyes see a lot better than sensors in most videocameras. Your eye is also more sensitive to color than the best color displays.And there are two devices you need if your HDR video is going to work at all:an HDR video camera to shoot your video and an HDR video display to show it on.

Displays first: They’re inherently less complex thancameras. There are only a few HDR displays, and they are at the top end inprice—not quite mainstream. To make matters even more complex, there aremultiple standards for HDR video. It’s sort of like Betamax vs. VHS is happeningagain right now. There are also what are known as “locally lit” displays. Eachpixel not only shows an RBG color, it can also be bright or dim. I’ve seen oneof these kinds of displays in demo mode, and it is indeed spectacular. Thereare several in production and they are enormously expensive, as are all newthings tech. A little 36-inch-or-so display still costs about $3,500.

The human eyeball has a dynamic range that can go as high as20 f-stops (about 1 million to 1) contrast. That simply means we can see thingsthat are really, really dim and we can see things that are really, reallybright. This 1-million-to-1 ratio happens in different lighting conditions, sothe human eye is also adaptive. Video cameras (even many very expensivecameras) have a dynamic range of 8 – 10 f-stops. That’s a huge difference.There are also video cameras that shoot in the “video raw” format. They can goas high as 14 or 15 f-stops. Explaining f-stops and dynamic range of light iscomplex, and this is an overview, so I’m not going to go into more depth aboutthem in this article.

The problem

Since HDR video isn’t about resolution, it’s aboutsomething. Resolution is pixels, and past a certain point, you can’t see the added detail more pixels give. Really. It’s all aboutexposure—and more than one exposure at that. Still photography is easy: Justtake three different shots at different exposures and combine them. It’s apiece of cake when you’re doing something like a landscape (and it’s notwindy), but gets more difficult when you’re shooting a portrait, and impossiblewhen you’re shooting action like car racing or even something slower. Videoexacerbates the problem by having all those pesky frames get in the way: 24 or30 of those frames each and every second. And to make matters more difficult,your subject is moving, even if the movement is nothing more than their lipsflapping. So instead of still HDR exposures, in which we can take three shotsin rapid succession, video is a wholly different story.

The event horizon is now

A few years ago, a few video camera makers introduced consumer-levelHDR video cameras. Are they any good? It doesn’t matter in a sense. Thesecameras are all under $1,000. And that was in 2015. Here’s a little articleabout the Panasonic cameras for HDR video production. The cameras do make two exposures and “blend”them on the fly, but it’s not quite HDR. Other makers like Sony have similarcameras and use similar algorithms to create their HDR image. This is about asfar as the HDR processing can go today. Real HDR is spectacular. On a largescreen like a movie, we only look at one thing at a time on the screen. Thatone thing covers about 10 percent of the entire viewing area. DSLRs always seemto be behind video cameras in their features, but none of them can do HDR videoyet. You can hack some Canon models to make HDR video, but because it’s a hack itvoids any warranties. So if you’ve got an older Canon, maybe it’s worth it. Thecamera still needs to make two or three exposures pretty much simultaneously.

We’llsee a lot about HDR video in the next few years as the display prices begin tocome down and cameras get better at it, and—and this is the big and—we start seeing content for HDR.I personally wouldn’t care if it’s HD video or 4K video. I’ll see it the same, andso will you. HDR changes almost everything we know about video and how we’llperceive what we watch. Even better for eLearning. The more we can show ourlearners and the clearer it is, the more we can all learn.