PACIFIC PALISADES—As stakeholders and standards organizations continue developing the “next big thing” designed to expand visual storytelling and sell new display technology, the discussions have focused mostly on resolution—spatial resolution, as in 4K, 8K and beyond, or temporal resolution as in high frame rate. A third way to increase the amount of image detail, high dynamic range—which we’ll call HDR, even though other names, such as extended dynamic range have been used—is also finding interest within the industry.
Dolby, through its Dolby Vision product, is among the companies most advanced in developing HDR video technologies. People in various aspects of production and post have viewed material mastered for Dolby Vision and presented on the company’s prototype monitor. The images, with their significantly increased contrast range—more detailed and brighter highlights, as well as shadows, more pronounced differences throughout the gray scale and wider color gamut‑have impressed many who’ve reviewed them.
Among those involved in HDR testing is former Disney technology executive turned director Howard Lukk (the short, “Make Believe”), who decided to make a live-action short, “Emma,” with HDR in mind. Produced by Pannon Entertainment’s Andrea Dimity, who collaborated on Lukk’s, “Make Believe,” “Emma” was designed to work within the dynamic range of standard HD display and theatrical projection, but also to benefit from HDR.
“We picked dark colors that other productions avoid,” Dimity said. “We have a dark car in low light with bright taillights. It’s the kind of situation that filmmakers would either stay away from or use lighting techniques so the differences from light to dark aren’t so extreme. But this was exactly the kind of scene our cinematographer, Daryn Okada wanted to experiment with.”
Lukk said, “We will still be able to make the scenes work with traditional displays but we’ll have to do what you always do in the color grading process and tone map the images to ‘fit’ within the contrast range of the display. So you always either ‘flatten’ them out a bit or you use windows to bring particular portions into the range that you’re going to be able to display. For ‘Emma,’ we also did a second grading pass that can take advantage of a higher dynamic range display.”
It is important here to make a key distinction between the HDR display and HDR image capture. The latter is an expression of how many stops of information a sensor (or piece of film neg) can record. Cameras such as the ARRI Alexa, Sony F65 and Red Epic boast advances in dynamic range through sensor and processing technology. But when those images are mastered for display, they all still need to be tone mapped to “fit” into the dynamic range of the display. This will still be the case no matter what the dynamic range is of the display. Mankind may never see a panel that can display the true brightness of the Sahara Desert at noon, but a higher dynamic range gets us that much closer than today’s HD spec and therefore gives us images that look closer to reality.
Dolby has developed technology to display images mastered specifically for EDR (Extended Dynamic Range) in displays, with a wider color space and greater bit-depth than the .rec 709 standard. Companies including Adobe and color corrector manufacturers FilmLight and SGO, among others have embraced Dolby Vision technology, as have Netflix, Amazon and other content distributors. Manufacturers, including Sharp and TCL are also working with Dolby Vision as the technology develops. At this point it is not clear to what extent the .rec 2020 spec would be involved.
Although their plan is to sell their IP to set manufacturers, they have built a prototype monitor. The processing technology,“will soon be available to manufacturers to enhance the contrast ratio of their displays,” said Roland Vlaicu, Dolby Laboratories vice president of Consumer Imaging. “It is important not just to make displays better but to make the signal going into the displays better than that 20-year-old .rec 709 signal that is limited to 8-bits [per channel] and has such low fidelity in terms of dynamic range and color.
“We are working on this HDR concept by changing the delivery mechanism itself,” Vlaicu said. “We are building an entire ecosystem, similar to what we’ve done with surround sound audio.”
While he admits that it would be completely impractical for any manufacturer to attempt to mass produce a display with the dynamic range of Dolby’s very power-hungry prototype monitor, Vlaicu emphasized that future developments could change that. Furthermore, Dolby Vision is designed to be scalable so that a TV with less dynamic range than their prototype but significantly more than today’s HD panels, could ingest the images mastered for the highest dynamic range and tone map it on the fly (through internal circuitry designed by Dolby) to work for that screen.
This scalability could allow programming mastered for the highest possible display dynamic range to offer the benefits of increased display dynamic range—say on next year’s sets—and that same signal could make use of the even greater dynamic range in three years when the sets can offer “Super High Dynamic Range.”
Throughout the industry, creative professionals like Lukk and Okada are experimenting with the artistic possibilities offered by high dynamic range displays while manufacturers are working on ways to monetize and standards groups are figuring out how to write new standards or adapt the next-gen HD specs from recent months that may already be out of date.
In short: whole thing is almost as confusing as it is exciting.
