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Automating HDR Look Management With Real-time Color Transforms

The global high dynamic range (HDR) market is expected to surpass $126 million by 2030, according to Allied Market Research. The projection shouldn’t come as a shock to media and entertainment (M&E) professionals who have been delivering HDR content for platforms like Netflix, Hulu, Disney+, and others for years. Meanwhile, HDR-capable displays have become standard in most production and post environments and across consumer displays. With these developments, HDR has emerged as the preferred production standard, and with just cause; HDR enhances imagery in ways resolution alone can’t while making for a more dynamic audience experience.

However, achieving a consistent, color-accurate look from lens to delivery in HDR productions can be challenging. A combination of HDR and SDR source footage must move across many different types of production gear, including cameras, lenses, monitors, and workstations, with the potential for varying colorspace support on each. Thankfully technological advancements are streamlining this process, making real-time color transforms much more accessible to ensure productions can fully realize their desired final look.

The Case For Real-time Color Transforms

Broadcasters and studios are creating content around the clock, yet projects often demand complex workflows for rendering, uploading, and sharing content. This can lead to costly logistical headaches, but it doesn’t have to. When it comes to look management, teams can take steps early on to cut out unnecessary media generation and ensure a more streamlined workflow and faster turnaround, such as embracing a predictable real-time color transform pipeline.

Between the myriad SDR and HDR sources at play in a given production, real-time color transform pipelines can help you manipulate a live signal along its path. This way, teams can easily pass the signal from device to device or generate accurate imagery for displays. One often sees this in live production and on-set production, post, and delivery.

Content is often tweaked, adjusted, and rethought depending on creative decisions – potentially multiple times. The result is massive files, which require long render times and increase pipeline costs, especially in a world where cloud storage adoption is growing.

If your preferred HDR palette transforms are described and transported along the path, you can manipulate the content live and maintain image quality without adding extra rendering steps. For example, suppose you’re moving content through a replay system. In this case, you can deliver the source material to that replay system in the necessary format (i.e., SDR), return that replay source feed, and use technology to convert it into HDR in real-time successfully. Additionally, having high-quality source footage with all the necessary information attached and laid out at the start of a project enables post houses to accelerate deliverable turnaround.

At the end of the day, being able to see and monitor color transforms in real-time can deliver unmatched efficiency and storage savings. Flexibility is also crucial, as there are various approaches to creating and managing Look Up Tables (LUTs), digital files that transform the color and tone of imagery.

LUT Methodology Considerations

While LUT approaches vary based on factors like environment, personal preference, or the broadcaster’s terms, there are two primary paths. One method produces predictable results, whereas the other provides more creative flexibility. For a live sports production, a crew might opt for a “set and forget” strategy using NBCU or BBC HLG conversion LUTs. Yet, others may prefer to maintain creative intent with proven color science like Colorfront offers. Still, some opt to use floating-point math to ensure greater precision via ORION-CONVERT or generate customized LUTs that meet their specific “look” criteria for live or scripted productions. Additionally, productions may desire a specific “Look” LUT, based upon creative decision-making, that they would like processed into the final HDR delivery format, whether HLG or PQ. The industry demand here is flexibility.

Each approach holds unique benefits, but technological advancements are making it easier to combine them. Using a real-time LUT color transform tool like AJA ColorBox and the AJA Color Pipeline, a crew can load an NBCU or BBC HLG LUT and combine it with a custom production LUT. They can then tweak the color and luminance signals with ProcAmp and color correction tools to achieve their desired outcome.

Examining Look Management Demands On-set And In Post And Live Environments

On set, DITs need a solid, reliable LUT box for 4K/UHD SDR or HDR monitoring and to apply color processing pipelines in real-time, especially since you may start with a particular camera’s log signal. Ideally, the box integrates with on-set color and look management tools like Pomfort’s Livegrade Studio and Livegrade Pro, and Assimilate’s Live Looks and Live Assist, which AJA’s ColorBox does. These integrations help DITs adjust content decision lists (CDLs) in their preferred software and see the output in their target format in real-time. ColorBox offers configurable on-screen overlays to display pipeline configuration data, such as loaded LUTs, video formats, and customizable user text fields; this is key for keeping decision-makers informed. Unique 4K frame capture and recall capabilities of the input or processed output further ensure DITs can provide the highest resolution reference images to others in the production pipeline.

For dailies and post production, tweaking or auditioning looks in real time must be straightforward. To this end, access to LUTs used earlier in the day for application during playback is immensely helpful and can be done with ColorBox and an HDR-capable display. You can upload a LUT directly to the ColorBox, negating the need to render footage from an NLE or color grading software so that editors can test and preview different looks in real-time during post.

To maintain a consistent look for live production, having support for LUTs is another consideration. One needs to be able to instantly convert SDR sources into a master HDR production format (or vice versa). This approach allows your team and others to mix all feeds in the same dynamic range and color space to the production switcher, then convert the program output to multiple different deliverable formats. AJA ColorBox is particularly helpful in this respect, as it processes video in less than half of a video line, which is within the input timing window of most production switchers, ensuring no delay.

In virtual production environments, a LUT device like ColorBox can be used to apply a color grade and transfer it to a viewing station on-set to fine-tune looks on the real-time composites. Whatever the environment, communication is key.

The Importance Of Communication

The value of communicating information about the intended look – including the LUT and color space conversion – as it moves across key production stakeholders cannot be underestimated. Tools like ColorBox that allow pipeline configuration overlays with text fields can ensure configuration data is retained and shared accurately. DITs and other team members can then enter custom information (i.e., camera and lens type, standard or high dynamic range, etc.) and node status (i.e., on, off, enabled, disabled, file loaded, etc.) and overlay the information onto a video output, or to a high-quality 12-bit .tiff file or other standard image formats, via its integrated 4K framestore. All the image details and file names used to create it can be baked into the image for communication downstream with the proper context, providing accurate high-resolution reference images to anyone who needs them.

ColorBox also offers presets that allow multiple parties across the production chain (i.e., on-set, editorial, grading, etc.) to share and access presets so that everyone works from the same look. All settings and associated files loaded into AJA Color Pipeline nodes can easily be exported as a single preset file with all the others nested inside. When a team member shares the original image created on set, they can load the preset, and the device automatically populates the library with all the files used to create the look. It configures the color pipeline as it was seen on-set.

Color management is becoming more pivotal than ever to the content chain, but it doesn’t have to be a task that professionals dread. AJA’s ColorBox addresses all the standard LUTs used on set and enables algorithmically based in-line color transforms for true, real-time color management. It provides a reliable nexus where professionals can handle the real-world challenges that color transforms pose for projects requiring multiple deliverables, whether HDR or SDR. Given the amount of HDR roundtripping required in modern productions, the device also offers a conduit between the most popular HDR, SDR, and WCG transformation approaches.

With support for NBCU or BBC HLG LUTs, as well as ORION-CONVERT and Colorfront methodologies, it allows teams to maintain creative intent. Plus, it brings the flexible AJA Color Pipeline, which features support for 1D LUTs, 3D LUTs, and 3x3 matrices, as well as ProcAmp and color correction controls. Packed into a compact and portable design, AJA ColorBox provides an unprecedented range of options specifically designed to address color management needs on-set, and in post and live production settings. It’s a one-of-a-kind device providing unparalleled flexibility and real-time customization.