What You Need to Know Before Buying a New HDR-Ready TV

LG UHD TV - S 2016
Courtesy of LG

Before you buy that new HDR-ready TV, consider this: In the eyes of many professionals, HDR, which stands for high dynamic range, brings a “wow” factor to television with dazzling images that have a wider range between the whitest whites and blackest blacks. But while the current generation of HDR-ready TVs support content from the HDR-ready Ultra Blu-Ray format and streaming services such as Netflix and Amazon, they may not be able to properly display content from HDR broadcasts, since a standard has yet to be decided.

In fact, since there are varying ways of producing, distributing and displaying such images, an HDR format war could be coming. The question is, will it be avoided through professional standardization efforts or will the problem escalate to a protracted and public battle?

At last week’s National Association of Broadcasters Show in Los Vegas, there were lots of HDR-related content announcements (Universal and Netflix have more 4K Ultra HD and HDR content on the way), new supported products (consumer TVs and production tools) and plans to include HDR in developing the next generation of television broadcast standards.

But despite a lot of forward movement, a lack of standards, particularly in how to handle broadcasting for live events such as sports, might mean problems down the road — for both consumers and Hollywood. While consumers might have to decide between sets supporting different HDR formats, Hollywood may need to make multiple versions of each movie or TV series to accommodate the different delivery methods, and that could mean added time and expense. “It’s a mess right now,” in the words of one insider.

“[Hollywood] has no control of what the broadcasters do, but it will have ramifications on how content is made. That’s why they have a nervous eye on what the broadcasters do when it comes to HDR,” Howard Lukk, SMPTE director of standards (and former director of production technology at Disney), told The Hollywood Reporter.

“From the Fox studio perspective, we spend a lot of time and effort to master content in the best possible way, and we want distribution to preserve the creative intent as much as possible,” said 20th Century Fox CTO Hanno Basso, who also chairs the UHD Alliance. “We’d prefer it be one master.”

There are primarily two approaches to broadcasting that are being reviewed by standards bodies, and broadcasters ultimately will decide which one to use. The two are Perceptual Quantizer (PQ), which was primarily developed and led by Dolby, and Hybrid Log Gamma (HLG), developed by The BBC and Japan public broadcaster NHK.

The PQ effort already has some traction in Hollywood, as it is the basis of both Dolby Vision and HDR10, two HDR formats that are currently supported by the new Blu-Ray standard, as well as content from certain streaming services and select studios. While TVs from Sony and Samsung support HDR10, LG and Vizio offer TVs that can play both formats. In fact, many think both Dolby Vision and HDR10 could continue to co-exist, and Dolby asserts that an HDR10 version can be extracted from a Dolby Vision master without requiring a second, full postproduction process.

The HLG approach aims to use one master for both HDR TVs as well as today’s standard dynamic range TVs. “New Ultra HD TVs are selling like hotcakes, but we can't ignore existing TVs,” said The BBC’s Andrew Cotton, explaining that the idea for HLG started in early 2013 when BBC execs saw the Dolby Vision HDR system. “They showed spectacular TV pictures … but it would have required a complicated encoding system to deliver to both standard dynamic range [today’s TVs] as well as HDR displays. And it would have needed two separate color grades [for each version]. We just couldn’t see how we could deliver that type of experience to our audiences. TV is run on a shoestring budget and can’t afford two color grades.

“Also I can not see how you can realistically use PQ for TV workflows where you have to have a continuous output,” he added. “Dolby has shown demos of PQ … but they don’t fully represent the complexity of TV’s challenges.”

On the Hollywood side of the equation, numerous pros argue that the HLG approach would compromise the quality when the image is displayed on HDR-supported TVs, since the system is trying to accommodate both versions. To that point, Cotton responded, “The HLG picture is pretty much identical to the PQ; you will not see a difference. We did some tests ... and it’s a compromise we have to make for standard dynamic range, anyway; we can't afford to do two grades.”

Dolby argues the opposite. Said one exec: "At the point of encoding, the broadcaster has the option to add dynamic metadata which will work with Dolby Vision-enabled devices to render back a better picture regardless of the color volume of the playback device. So bottom line, you don't need a separate version or grade for a live PQ workflow."

Ultimately, these are among issues that standards bodies and broadcasters must make decisions about.

It’s quite possible that both HLG and PQ could end up in use, either in different countries or used by different broadcasters. NHK, which demonstrated HLG at NAB, is scheduled to begin test broadcasting of its 8K Super Hi Vision system this summer during the Rio de Janeiro Olympics.

The in-development  "ATSC 3.0" next-generation TV broadcast system, which will be proposed as an option in the U.S. market, also was demonstrated at the Las Vegas convention. But its makers haven’t yet finalized which HDR approach it will take.

Technology manufacturers seem to think both PQ and HLG will prevail. Widely used postproduction tools that already support both PQ and HLG include Blackmagic Design’s DaVinci Resolve, FilmLight’s Baselight, SAM’s (formerly Quantel) Rio and SGO’s Mistika.