Exploring the Role of Static Diffuse White Feature for Effective Graphics Management

Q: Are we approaching a tipping point where more live production content is captured in HDR rather than SDR?

Valerie Allié: Absolutely. We’ve already experienced a huge uptick in live sporting events that are now captured in HDR instead of SDR. We are also seeing companies like Sinclair Broadcast Group (SBG) move forward rapidly in enabling dozens of their affiliate stations in the United States to broadcast 24-hours a day in ATSC 3.0 and HDR, including live sporting events from SBG’s sports properties such as the Tennis Channel.

Live sports is an area where HDR has become mainstream. However, even when the production is in HDR, there is still a need for delivery in both HDR and SDR. This means the constraint to produce HDR and SDR simultaneously on complex workflows is still part of the overall production and broadcast equation.

Q: For a long time, the HDR discussion has focused on upconversion — enabling SDR signals to be consumed in HDR — because of the lack of original HDR content. Does the growing availability of HDR shift attention to addressing new workflows that ensure effective down conversion to SDR?

David Touzé: The short answer is…yes. As we capture more content in HDR there is a growing requirement to create streamlined workflows in which a single master production for HDR content can also be seamlessly down converted to SDR. This is very important because there are still a lot of SDR devices in the market. But we have to ensure the complete coverage of end devices in a technically-effective and cost-efficient manner. A single workflow for producing HDR and SDR is critical for this to happen.

This is part of an ongoing conversation that has been taking place in the industry for years. When HDR productions were first introduced, it created concerns about ensuring SDR quality, which limited the effects of HDR. This created a dialog within the community about being conservative in HDR production.

However, this is changing.

The community now recognizes that it is possible for content shot in HDR to be of exceptionally high quality. As a result, there is a growing consensus that the best way to preserve this quality is to shoot without constraints to capture as much detail and lighting variance as possible and then use an effective conversion process to derive the SDR content. This approach, however, has some challenging issues that must be addressed when down-converting SDR streams.

Q: What are the challenges that need to be addressed?

Allié: The main issue revolves around the fact that current single master workflows rely on static conversion solutions. This approach has known limitations, including difficulty managing light-changing conditions, color consistency and loss of detail.

In addition, static approaches exist with multiple settings requiring manual adaptation for each production, often resulting in interoperability conflicts and complicated workflows. As a result, additional solutions were needed to solve these issues while preserving premium HDR and good SDR quality.

That is why we have been working on creating a dynamic approach to developing single master workflows that deliver uncompromised quality, consistency and fidelity to creative intent for both HDR and SDR content production.

Q: Can you explain how a dynamic approach works to create single master workflows?

Touzé: Dynamic solutions adapt to the content, preserving detail in the bright and dark areas of content being captured, depending on the scene and lighting conditions. They provide more flexibility and freedom for the content producer when creating HDR content. When converting HDR to SDR, dynamic solutions offer the added benefit of frame-based conversion.

Graphics insertion also presents a constraint in single master workflows. As graphics are inserted in the HDR single master, they must be properly managed and remain stable when converted to the SDR output stream.

Dynamic down-mapping solutions are able to address this challenge, ensuring graphics remain stable in down-converted SDR streams and still maintain the creative intent of the HDR content.

Q: Can you tell us how Advanced HDR by Technicolor is helping the industry address these issues?

Touzé: Advanced HDR by Technicolor has a new static diffuse white feature to help broadcasters and content creators better manage conversions by carefully managing luminance levels.

When you effectively manage luminance levels that fall below the diffuse white – with all the details and colors – and the speculars that fall above the diffuse white, you can deliver the best image quality across HDR and SDR content.

The new static diffuse white feature in Advanced HDR by Technicolor was specifically designed for graphics. It combines the dynamic nature of down-conversion with the fixed static diffuse white level.

The feature sets a fixed HDR diffuse white level corresponding to the white level at which the graphics are inserted in HDR content and a fixed SDR diffuse white level corresponding to the SDR level to which the HDR diffuse white level is converted.

All the HDR content below that HDR diffuse white setting is dynamically down-converted to SDR, up to the SDR diffuse white setting. This ensures the most appropriate conversion and allows content creators and broadcasters to adjust the content’s brightness, saturation, and contrast.

All the specular HDR content above that HDR diffuse white setting is converted to SDR above the SDR diffuse white setting, allowing the preservation of highlights.

Q: Does this process preserve backward compatibility between today’s dynamic workflows and legacy static LUTs processes?

Allié: With this new static diffuse white feature, Advanced HDR by Technicolor ensures compatibility with existing static workflows. This allows the industry to transition smoothly from static to dynamic solutions and ensure premium HDR and SDR content delivery to consumers.

EDITORIAL NOTE: The new Advanced HDR by Technicolor feature will be showcased during the NAB 2023 conference at Cobalt Digital’s booth #C2108.