Want to see the Dolby Vision HDR format in action? You can check it out at the El Capitan Theatre on Hollywood Boulevard, where Disney’s Tomorrowland—the first film graded for Dolby Vision—is enjoying a four-week run. AMC has the system installed in one auditorium each at the AMC North Point Mall 12 in Atlanta, the AMC BarryWoods 24 in Kansas City, and the AMC Deerbrook 24 in Houston. On May 29, those theaters replaced Tomorrowland with San Andreas, the first Dolby Vision title from Warner Bros. Pixar’s Inside Out, opening June 19, will be the next fix for HDR junkies who crave brighter whites and broader dynamic range
The key to efficiently encoding all of the brightness information in a HDR picture for Dolby Vision is something called the perceptual quantizer, or PQ for short. Dolby researched human visual perception of luminance changes, then developed a new quantization curve based on those findings. The goal was to specify brightness levels from 0 to 10,000 cd/m2 using 10-bit or 12-bit encoding. The resulting PQ curve, approved as SMPTE Standard 2084, replaces gamma for Dolby Vision image encoding. In post-production, this means the image must be graded twice—one time for the standard P3 color space that most cinema viewers will see, and then again in the PQ format that specifies characteristics of the HDR version. Read this 2014 SMPTE presentation by Dolby Labs researcher Scott Miller for the nitty-gritty.
Tomorrowland was graded on DaVinci Resolve at Company 3, where Stephen Nakamura said his goal in the 31.5 foot-lambert Dolby Vision pass was to make sure the picture took advantage of the expanded dynamic range while still retaining the feel of the standard 14 foot-lambert version. He elaborated on the grading process, and the thinking behind some of the creative decisions, in a statement released through Blackmagic.