David Mouen

By: David Mouen on May 14th, 2020

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DTT Evolution: Unified Headends for Spectrum Efficiency and New Compelling Streaming Services

An evolution is underway in the digital terrestrial television (DTT) environment. Major market and technology developments, including the rollout of 5G networks, are shifting consumer viewing habits and driving change.

Around the world, some broadcasters are faced with government mandates to free-up DTT spectrum to help accommodate 5G. In reaction to the loss of spectrum and the threat of streaming services, the objective of broadcasters is to improve the viewer experience by offering at least the same channel lineup, better video, and audio experiences and streaming services, as well as activate new revenue sources.

Broadcasters need solutions to face these market and technology changes as well as to ensure business continuity. Unified broadcast and streaming headend solutions are at the forefront of this change, based on the efficiency and cost-effectiveness they provide.

Short-term and long-term improvement of spectrum efficiency

Today, the majority of DTT services are transmitted in Europe via the DVB-T standard, relying on MPEG-4 as the video compression technology. The DVB-T2 standard and HEVC compression are the next frontiers for DTT, offering a capacity improvement that enables broadcasters to double the number of HD channels compared with DVB-T/MPEG-4.

The migration to next-generation DTT standards and compression technology will be slow and gradual. It’s a transition that is being driven by government guidelines and consumer device adoption. Currently, there are already tens of millions of DVB-T/MPEG-4 decoders in the field. Broadcasters won’t make the switch until at least +90% of TV sets can receive DVB-T2 / HEVC signals. And this will take some time, at least four to seven years, depending on the countries.

This long-term migration plan to DVB-T2/HEVC does not really match the 5G rollout time frame.  In many countries, the 5G rollout will ramp up in the next six to 18 months, and the 700 MHz band has been allocated to mobile operators for 5G use. In order to use less spectrum, broadcasters are looking at solutions that help them to optimize current DVB-T/MPEG-4 AVC spectrum efficiency

What are the DVB-T/MPEG-4 AVC optimizations broadcasters can deploy in the short term? First, improving the AVC video codec with machine learning and artificial intelligence algorithms is an effective short-term solution to boost bandwidth efficiency and still provide exceptional video quality. Machine learning and AI algorithms can achieve 20% bandwidth savings versus traditional encoding solutions. Second, delivering more streaming services is another option to reduce pressure on the spectrum and it’s a way to provide new compelling services, such as live UHD, time-shifted TV, VOD, and regional content.

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Streaming to boost the broadcast offering

Today’s DTT broadcasters have high expectations to constantly improve the user experience. Viewers today want more services, including regional content, better video quality, and immersive audio.

Streaming services may seem like a threat to broadcasters because viewers have access to a huge amount of content. But broadcasters can turn that threat into an opportunity by delivering streaming services in addition to their broadcast offering. This includes complementary linear services, time-shift TV (catchup, start over, nPVR), VOD, and more personalization.

Delivering a UHD service requires two to three times more bandwidth compared with HD. Some UHD DTT trials are underway today, but there are no known plans for DTT broadcasters to launch UHD in the short term, at least in Europe.

With advancements to the low latency scheme for streaming (i.e., DASH and HLS), it is now possible to mix and match broadcast and streaming services without a noticeable difference in delay between the two delivery mechanisms. Broadcasters can offer a UHD experience 24/7 by using other delivery channels for UHD, while HD is transmitted over the air (OTA).

So how does a broadcaster bridge to streaming? The HbbTV standard is a mature option. It’s currently deployed in 37 countries and offers a path to the streaming world. Through HbbTV, broadcasters can deliver broadcast and streaming services that seamlessly transition between each other and to connected TV and set-top boxes. Offering regular streaming services to any device is the second path into the streaming world.

Personalizing ads can unlock new revenue for broadcasters

With the changing streaming and video delivery contexts, broadcasters are looking to find new revenue sources. Delivering customized advertising based on region and individual households represents a huge opportunity for revenue generation. It’s also an opportunity to meet the viewer's demand for personalized, relevant content.  

In a few years, broadcasters will be able to deliver targeted advertising on HbbTV connected TVs using the future DVB-TA standard.

In the streaming environment, dynamic ad insertion (DAI) has emerged as a way to unlock new revenues. With DAI, broadcasters can insert advertising in a programmatic way into linear and nonlinear streaming services. They can also address individual viewers over any type of device. DAI is a server-side technology. This approach to ad insertion avoids interactions between the player and ad servers, which eliminates the adblocking, buffering, and latency when switching between content and ads.

Service continuity is a strategic requirement

Service continuity is critical for all types of broadcast. It’s probably even more important for DTT since many governments consider DTT to be a strategic infrastructure. The significant cost involved with building an additional headend for backing up content and ensuring service delivery is a challenge.

Securing the delivery of a major event for a few hours or day or securing the complete DTT platform is a must-have. Using a cloud-based SaaS platform for service continuity is cost-effective, as you pay only for what you use. It’s highly reliable and can be activated fast.  It becomes a clearly advantageous alternative compared with having to recreate the entire infrastructure with a second set of hardware.

Harmonic unified headends ease the migrations underway in DTT world

Delivering your broadcast and streaming service from a unified headend will help you streamline your infrastructure. For instance, the same sources are used for both deliveries, reducing operational costs. The same monitoring room, encoders, and distribution technology are also used, optimizing support through a single SLA.

Harmonic has already deployed unified headends, on-premises and in the public cloud, meeting all of our customers’ goals and requirements. A unified headend allows you to generate your DVB-T/T2 multiplexes and to deliver linear, nonlinear, and VOD services, as well as personalized content such as targeted advertising. And all this content is delivered simultaneously.

Boosted with the latest AI algorithms, the PURE Compression Engine™ brings at least a 20% improvement compared with current-generation encoders, solving the short-term spectrum efficiency challenge, as well as the longer-term migration to HEVC.

And with Harmonic’s cloud-native software and VOS®360 platforms, you can replicate all, or even just part of your on-premises workflows in the cloud, easily and in minutes. You can maintain business continuity with minimal effort. 

Want to learn more about how to optimize terrestrial broadcast service delivery?

Harmonic is an industry expert in DVB-T/DVB-T2, AI compression, UHD, DAI, HbbTV, cloud business continuity, and unified broadcast and streaming delivery. If you’re a player in the terrestrial broadcast world looking to leverage global change to create opportunity, then contact us today to start a discussion.