December 17, 2013 4:17pm PT by Carolyn Giardina
Dolby Proposing Disruptive New Imaging Format, But Can It Slow The 4K Train?
While 4K TV has been building momentum with January's International CES approaching, Dolby is looking to put the “icing on Ultra HD” by proposing not just more resolution, but higher frame rates, wider color gamut and higher luminance.
The difference is noticeable enough that it has Hollywood's engineering community considering this proposal as a way to bring greater perceived value to consumers--and Dolby confirms that there will be major third-party set makers unveiling consumer displays supporting it recommendation at CES.
But this is easier said than done, as it would require a revision to the Ultra HD standard that the International Telecommunication Union set just 18 months ago. That could effectively render currently-shipping Ultra HD TVs out of date as they don’t support Dolby’s recommendation.
It also creates another ‘chicken or the egg’ scenario. On the consumer side, TVs supporting this imaging recommendation would be needed in the home.
On the production side, there would be a need for content shot and graded to support this recommendation. According to Dolby, high-end digital cinematography cameras—such as Sony’s 4K F65, Red’s Epic or Arri’s Alexa shooting Arriraw, for example—can be used for production. It also requires color grading that meets the requirement, and Dolby said it is developing a plug-in for existing color grading systems that would offer this support.
A reference monitor would also needed so that filmmakers could see this color during production and post.
To that end, Dolby has started to preview a prototype reference monitor, which it said has the same 2K panel as its PRM4200 professional reference monitor, but with increased backlight of about four times more LEDs. In the demonstration, Imagery graded to meet the Dolby recommendation was shown on this prototype display, with a side-by-side comparison of the same imagery playing on its existing PRM4200. The improvement to the image on the prototype display was remarkably evident.
Dolby confirmed that there are only a few of these prototypes available, and we could expect to see these arriving at clients’ facilities for further experimentation. Dolby declined to comment when asked if there would be movie production beginning this coming year that would use this recommended format.
The thinking behind Dolby’s proposal is this: Digital television pictures are made up of building blocks called “pixels,” and to improve a picture, the industry can address a few parameters. First, it can add more pixels (known as resolution), for instance with 4K, which is four times the number of pixels found in today’s HD.
It can also offer faster pixels (higher frame rates), which addresses image artifacts such as motion blur. The third variable – so called “better” pixels --involves a higher luminance range (brighter and darker pixels) and wider color gamut (more colorful pixels). Dolby believes that if the industry is to move to a new format, all three should be addressed.
“You can see [a difference] with more pixels, but only when you are close up,” said Pat Griffis, Dolby’s executive director of technology strategy. “Brighter pictures you can see from across the room, so ‘better’ pixels may well be the low hanging fruit to consumer-perceived value.”
“Better” pixels involves examining the wider range that the human eye can perceive. Using “nits” as the measurement of light intensity, Griffis related that direct sunlight can reach 1.6 billion nits while starlight can be 0.0001 nits.
Griffis pointed out that while it’s unlikely that any single image will vary that dramatically, a still outdoor image (see the above example), might include direct sunlight that could produce 330,000 nits on a car, while the light on nearby foliage might only reach 40 nits.
According to the exec, today’s TV displays have a far more limited range that only reaches approximately 100-120 nits for the brightest white, while cinema caps at just 48 nits (14 FootLamberts) for the brightest white. In contrast, the aforementioned prototype display, he said, is capable of reaching as much as 4000 nits.
Dolby is recommending that a next-generation Ultra HD format should range from zero nits to 10,000 nits, which it believes is an achievable goal. On bandwidth requirements, Griffis said that it would effectively double for 4K [using HEVC compression] and “better” pixels would add another 25 percent or so compared to what is used for today’s HD [using AVC compression].”
The Hollywood Reporter previously provided a look at Dolby's research here http://www.hollywoodreporter.com/behind-screen/why-4k-might-not-be-636485