As TV audiences prepare to gorge themselves on a feast of sport over the summer, it is being argued that there is a misconception within the industry that HDR is associated solely with 4K content.
The team behind Advanced HDR by Technicolor—a collaboration between Philips, InterDigital and Technicolor—suggest that adopting high-dynamic range (HDR) strategies for content creation and distribution can help broadcasters and streaming services improve the user experience with better video quality, faster load times, intuitive interfaces, and seamless integration with other devices and services.
According to the head of business development for wireless and HDR at Phillips, Rick Dumont, streaming services that leverage HDR in HD can offer audiences content with improved colour, contrast, and greater overall image quality.
“The market does not understand that HDR—especially Advanced HDR by Technicolor—allows for a better viewing experience on HD TVs. This is significant because, globally, the lion’s share of available content is still in HD (2K) and not UHD (4K),” states Dumont.
“Many people assume that HDR is married with 4K content, but that is not the case. By implementing HDR technology on full HD content, viewers can enjoy improved colour, contrast, and overall image quality. They can have a more immersive and visually appealing experience.
“In fact, HDR over HD has a more significant visual impact than SDR over UHD because HDR presents more accurate colours, smoother light and colour shading, and more detailed images.
Dumont adds utilising HDR over HD content reduces bandwidth requirements by a factor of four because HD uses only one-fourth of the pixels.
“This leaves us with the challenge of providing high-quality HDR with 8-bit coding when, theoretically, a 10-bit colour depth is needed. However, this issue can be effectively addressed,” he continues.
“The bottom line is that HDR on HD is ideal for meeting the requirements of broadcasters and service providers that seek a bandwidth-efficient streaming or broadcasting solution for delivering significantly more vibrant video content.”
HDR uses 10-bit bit depth to prevent coding artefacts like “banding”, but with SL-HDR preprocessing, the dynamic or adaptive nature allows coding to be used more efficiently compared to the static coding allocation of formats like HDR10 and HLG, states Dumont. “Where HDR10 needs a 10-bit bit-depth and typically HEVC coding, SL-HDR can use AVC in 8-bit as used by legacy systems, making it less bandwidth hungry and at the same time backward compatible with legacy SDR systems.”
From a content creation perspective, HDR over UHD content creation means more data is processed during editing, colour grading, and special effects rendering, he continues. But in contrast, HDR over HD content involves smaller file sizes and less demanding processing requirements.
“The single-layer HDR (SL-HDR) pre-processing done by Advanced HDR by Technicolor optimises 8-bit quantisation, leaving no visible coding artefacts like banding,” says Dumont. “In addition, the HDR and SDR formats can be stored and distributed in a single stream, halving storage space for the coding ladders.”
As most viewers are still watching on SDR-capable TV sets, broadcasters and streaming services will need to offer simultaneous support of SDR and HDR for video streaming and broadcast for some time. Dynamic HDR content conversion will allow native HDR video to remain uncompromised and be distributed at the best possible quality, while also making sure that the SDR video is of optimal quality and remains consistent, says Dumont.
“Dynamic conversions are also critical when capturing content, especially for live outdoor sporting events. Without dynamic conversion, the brightness levels of the HDR content would need to be manually adjusted continuously as lighting conditions can dramatically change when the action moves from a bright sunlight to shaded area,” he adds.
“Consider a football moving from bright sunlight to a shaded part of a stadium. Without a dynamic conversion from HDR to SDR this results in compromised viewing experiences for consumers with HDR TVs and suboptimal viewing experiences for those with only SDR-capable TVs.
“Hence, by automating the conversion process, HDR content can be delivered to the viewer in a stable and reliable manner, regardless of the viewing conditions or changes in lighting conditions.”
