HDR and SDR Content Management and Optimization Strategies for Streaming Service Providers
For many providers, high dynamic range (HDR) has been an “add-on” operating separately from long-standing production, distribution and consumption workflows. As demand for HDR content continues to rise, streaming service providers are wrestling with how best to manage the dynamic transition from a predominantly standard dynamic range (SDR) environment.
Consequently, leaders in the over-the-top (OTT) community are exploring ways to integrate and optimize their SDR and HDR operations to simultaneously deliver live and on-demand content in a technically effective and economically rational manner.
We caught up with Alan Stein, vice president of technology at InterDigital, for an overview of the options and issues streaming providers should consider as the market continues to evolve.
Here is what he had to say:
Q: What is the state of high-dynamic range (HDR) adoption in the streaming medium environment?
Alan Stein: It is actually in a pretty interesting state because, while HDR is pervasive, it is also very fragmented.
Here is what I mean: Almost every major streaming provider offers HDR content today. The challenge is that the content is created, managed and distributed in several different formats. Because of the nature of HDR’s evolution, there isn’t a clear winner in terms of a dominant HDR format across the different streaming service providers.
It is equally complicated at the endpoint. Current devices in the market — including set-top boxes, televisions, mobile phones and tablets — support some HDR formats…but not all.
So, it’s chaotic.
Having said that, a growing number of TV manufacturers offer HDR experiences. The reason is that consumers are much more likely to notice viewing improvements from HDR-equipped TVs than when they watch 4K-capable TVs. In other words, high-definition (HD – 2K) television with HDR compares quite favorably — often better — than UHD (4K) TVs displaying SDR.
As a result, there is growing consumer awareness of the difference between HDR and 4K, though the two are often bundled as “Ultra HD”
This is not lost on OTT streaming service providers. This is why they are embracing HDR for new content. The challenge is that — while the volume of HDR content is growing — SDR accounts for the majority of content in most libraries.
Q: What are the implications of this dynamic for OTT providers?
Alan Stein: Because the primary bread and butter of many streaming service providers is their library of content, we are now seeing growing interest in converting SDR libraries to HDR. This, however, raises an interesting series of creative, technical and economic questions.
On the creative front, content owners need to ensure that they maintain the creative intent captured in SDR when up-converting to HDR. Simply making content brighter can unacceptably alter the story artists were trying to tell. As a result, thought — and appropriate action — must be invested to preserve the essence of the original work.
There are significant technical consequences to making the same content available in SDR and HDR. Beyond addressing storage and distribution implications, there are issues around managing the various versions of content that must be encoded to support different applications. Improperly managed, this can raise the technical level of complexity.
Finally, there are the financial implications. Streaming service providers must understand how the encoding costs and time are managed as they develop their ladders.
A ladder is the number of different encodes that are created to support different resolutions, bit rates, and frame rates. Any given piece of content will likely require seven to 10 encodes. This number doubles if providers are doing different encodes for SDR and HDR. The video industry has recently worked toward mitigating the redundancy of encodes to support MPEG-DASH and HTTP live Streaming (HLS) ladders, but they have not yet addressed the HDR and SDR encoding overhead in any meaningful way.
Q: How can these complexities be managed?
Stein: The key is to harmonize encoding. One of the best tools, Advanced HDR by Technicolor, has a tool called, Intelligent Tone Management (ITM) that can up-convert SDR-produced content into HDR for distribution. The ITM tool has several configurable parameters that enable providers to deliver a look and feel suitable for different brands and content creators and can support both live and archival content.
Advanced HDR by Technicolor also includes single layer HDR (SL-HDR1) technology that allows a single-bit stream to be encoded and delivered as both SDR and HDR using metadata. This means that providers only need to encode content once to meet their ladder needs. It cuts in half the number of encodes and storage units, simplifying many distribution pain points.
One of the huge benefits of the SL-HDR1 approach is that upper layer signaling is not required. Content is delivered as SDR, and when it hits devices that support Advanced HDR by Technicolor, the low-level video decode identifies the SL-HDR1 metadata that enables HDR reconstruction. This strategy not only simplifies the process, but also consumes very little overhead resources while content is en route.
It is a capability that is not available in other solutions, so it is a key differentiator for Advanced HDR by Technicolor.
Q: Set-top boxes and smart TVs can read the metadata and make appropriate decisions, but what about cell phones and tablets?
Stein: Even when there is no chipset support for SL-HDR1, we can decode and reconstruct HDR through a GPU. Since all modern smart phones have a GPU, we can decode the video using the cell phone or tablet hardware decoder and subsequently process the SL-HDR metadata – which allows reconstruction of HDR– on the GPU.
Q: What other benefits does Advanced HDR by Technicolor solutions offer?
Stein: A very interesting conversation is emerging around the issue of sustainability. Video, for instance, represents a large (if not the largest) portion of internet traffic, which in turn accounts for nearly 4% of global carbon emissions.
One key benefit of utilizing a solution like Advanced HDR by Technicolor is that it offers a major opportunity for OTT providers to reduce their carbon footprint. As a result, an analysis is underway to determine how the three domains of streaming services — production, distribution and consumption — can be streamlined.
The tools in Advanced HDR by Technicolor can really make a difference in the overall energy consumption.
Q: What role does Advanced HDR by Technicolor play in elevating the streaming live entertainment experiences?
Stein: When people think of live events, they most often think about sports. While the broadcasting community has focused heavily on sports and news as one of their main consumer value propositions, we are starting to see live sports move to streaming. This raises a whole different set of issues around latency and scale.
Again, Advanced HDR by Technicolor offers a path forward for live content, as seen in its adoption and deployment in ATSC 3.0 over-the-air broadcast. Having one unified single workflow for HDR and SDR is a huge benefit for live, whether delivered via broadcast or OTT streaming.