HDR is one of the latest advances in video technology. Like the dawn of 4K, it means new standards and processes for video creators, and with it, video editors definitely need to learn what it means to their workflow.
HDR, as a term, is thrown around a lot these days and it’s not as commonly understood as other paradigm shifts in video technology. The resolution changes from Standard Definition (SD) video to High Definition (HD) video, and from HD to 4K, were easy to grasp as concepts: the resolution size of the video frame increased. As a result, the fidelity and quality of the video image increased as well.
HDR is a new change, it’s not dependent on the resolution of the video frame. Instead, HDR is an increase in the dynamic range of the image’s luminance values. This means an increase in the intensity of colors on screen, with greater detail in the shadows and highlights. Standard-Dynamic Range (SDR) video, the Rec. 709 color gamut standard of traditional video, displays roughly 6 steps of dynamic range. HDR, Rec. 2020, is a wide gamut color range with close to 18 steps of dynamic range. This results in higher details across intense areas of color and luminance, while at the same time contributing to significantly less color banding in the output video.
There are different formats of HDR, the reason being their promotion, support and development by different entities within the video industry. They offer slightly different but similar capabilities and varying versatility.
The two most common formats are HDR10 and Dolby Vision. HDR10 was one of the earliest HDR formats and Dolby Vision is being widely adopted as a format by Hollywood studios. One thing to note, is that many monitors and TVs that work with the Dolby Vision format can also playback HDR10. This isn’t necessarily reciprocal because Dolby Vision is a proprietary format and HDR10 is often used to avoid licensing from Dolby. Other formats include HDR10+, Hybrid-Log Gamma (HLG), and SL-HDR1. HDR that is in the HLG standard can be made backward compatible to work with SDR display devices.
HDR delivers such rich visual information that standard monitors, even high-grade monitors, won’t be able to display the range and color of a true HDR image. It’s important to use an HDR reference monitor. Fortunately, the price for HDR monitors has dropped significantly over the last couple of years. A reference monitor is a critical piece of equipment to edit and grade HDR footage.
A reference monitor is a critical piece of equipment to edit and grade HDR footage.
Depending on the setup of the edit bay, the reference monitors used, and the user’s computer, a video input/output device might be needed or at least desired to serve as an intermediary between the computer and reference monitor in order to maintain the highest possible quality image.
The good news is that most computers that are capable of editing 4K video, and support the current versions of major video editing applications (Final Cut Pro X, Adobe Premiere Pro CC, DaVinci Resolve, Avid Media Composer), are able to handle the editing and grading of HDR footage.
As stated, most major video applications are capable of editing and grading HDR footage. You should consider the platform that fits best into your workflow and is efficient in your set-up. Tools such as DaVinci Resolve have a robust environment for color grading and offer a great deal of creative possibilities.
While video editing programs are capable of working with HDR footage, you’ll still need to set your platform up to work with the increased dynamic range. During the project set up, make sure your color space is set to handle HDR. Normally, there will be a drop down menu under color space and the options will have a listing similar to: High-Dynamic Range, Wide Gamut HDR, Rec. 2020, etc. One thing to note, set up the color space in your editing program to match what you’ll eventually output. Adjustments made in an HDR color space won’t always translate to an SDR output and can look muddied or muted. One way to work through this is to do two grades to the footage, with one being a first pass that adjusts the overall image, enough to translate to SDR footage. The second grade will then be a detailed grade that adjusts the detailed areas of the image.
Working with HDR footage is similar in theory to working with SDR footage, but it takes some time to adjust because of the drastically increased latitude within the image. This gives you a lot more to work with and means you’ll need to spend more time with the image paying attention to the increased details. Some editors feel this hyper-detailed imagery allows them to move away from video scopes, but the truth is that the video scopes in any grading suite are one of the most reliable tools available to an editor. Video scopes work the same with HDR as they do for SDR, the only difference is that they are scaled differently. The clipping point for luminance in HDR is much higher than in SDR.
HDR imagery is one of the most visibly noticeable advances in video technology. The rich details and colors that are maintained are drastically different from even the highest quality SDR footage. If video editors want to show their audience the world, they can’t paint a much better picture than what they’ll get with HDR.
Chris “Ace” Gates is a four-time Emmy Award-winning writer and producer.