The HbbTV standard was introduced to enable hybrid broadcast broadband services, enabling broadcasters to provide catch-up TV and red-button style interactivity like news feeds, voting and quiz participation. It also offers a roadmap towards addressable TV advertising that is independent of Pay TV operators.
The technology means that when someone tunes to a participating broadcast channel, the HbbTV app is opened and the broadcaster becomes aware that this household is watching their broadcast signal (probably digital terrestrial or satellite). Broadcasters with developed data strategies can establish a link between the Internet-connected television set or STB and other IP-enabled devices in the home, and use this as the basis to ‘profile’ the household – one of the key building blocks for targeted advertising.
Using standard digital ad servers, and with no meaningful changes at the broadcaster backoffice, digital ads can be served to the hybrid broadcast/IP device over the open Internet. The viewing device is told to switch screen output from the broadcast (DTT/satellite) signal to the IP video advertising stream that is arriving.
The IP delivered advertisement temporarily replaces the broadcast signal. The device then switches back from the IP input to the broadcast signal. Broadcasters can choose how they use the IP-into-broadcast insertion. One option is to show an advertisement as soon as someone tunes into a channel belonging to the broadcaster. Another is to replace broadcast ads with IP ads within existing advertising breaks.
In commercial deployment, HbbTV has been largely used in Europe to insert graphical ads, with a classic example being the ‘overlay’ of IP-delivered L-shaped graphics around the programme that is arriving on the broadcast signal. These graphical ads can be interactive and can lead to more advertiser content if viewers want to explore them.
HbbTV advertising gets exciting when you explore the potential for inserting video ads rather than graphics-based ones. There is a well-documented and realistic roadmap that can lead the European broadcast industry towards IP-into-broadcast video ad replacement, but a recent Videonet webcast (‘Implementing Broadcaster Addressable TV using HbbTV’) left the impression that it could be years, rather than months, before we see HbbTV-based addressable TV deployed commercially on a large scale.
Frode Hernes, SVP of Product Management at Vewd, the TV software provider that enables HbbTV support on devices, gave an overview of the capabilities in each version of the HbbTV specification that help to enable IP advertising insertion.
In the version that is widely deployed on television sets in Europe, v1.5, you have auto-start of applications on tune-in (required since the original v1.0 spec to enable red-button type experiences), stream event signalling and support for HTTP adaptive streaming in the form of MPEG-DASH. HbbTV 1.5 supports the insertion of IP video into broadcast signals but lacks later features that make frame-accurate insertion possible.
HbbTV 2.0 was introduced in 2015 and was quickly replaced with HbbTV 2.0.1. Once you are working with this specification, frame accurate video insertion becomes possible. With 2.0.1 you get precise timing for synchronisation of broadcast and broadband streams plus support for pre-buffering/pre-caching.
In the world of HbbTV, pre-caching does not mean loading a series of 30 seconds advertisements onto a DVR. It can mean pre-loading a few seconds of IP video into the device buffer while the consumer is still watching the broadcast signal. And as Hernes made clear, the amount of video you can load into the buffer is device-dependent and could be 90 seconds in a high-end television or as little as 2-3 seconds on an entry-level television set.
When inserting IP ads into broadcast signals, the broadcaster provides markers to show when an ad break is coming and then when the ad has arrived. The digital ad server treats these as ‘load stream’ and ‘play stream’ signals. The digital ad server makes decisions about which advertisement to serve to that precise household.
The ad server is informed around 30 seconds before an ad break arrives, typically. Speaking on the Videonet webcast Leon Siotis, GM Revenue Europe at SpotX, the video advertising platform and programmatic pioneer that is part of the RTL Group, said the ad server can start delivering the content earlier than it would otherwise do if the receive device can handle pre-buffering. Post-impression, broadcasters are sent reports showing that an ad was viewed and how long it was watched.
Germany is one of the most proactive HbbTV markets and a firm leader in the use of HbbTV for advertising, with ProSiebenSat and RTL both using the technology for graphical ad insertion. RTL has tested HbbTV for true video ad replacement, as well. Siotis reported that in this market, SpotX ad servers are connecting to 18 million different HbbTV-enabled devices per month, most of them television sets.
When it comes to the specification version supported on these devices, “2.0+ support is a low percentage of the figure – between 5-10%”, Siotis told the Videonet webcast audience.
There are no quick fixes for getting more 2.0+ boxes into the market; some manufacturers do not even support the higher specification yet. Vewd’s Hernes pointed out that TV manufacturers will only add the higher specification if broadcasters create compelling services that need the higher spec, beyond 1.5, and so create consumer demand.
For this reason, Hernes thinks we need to focus on how the industry achieves a ‘good-enough’ user experience using the 1.5 specification, which means without frame-accurate ad insertion. He believes this is possible using what amounts to a fairly simple concept – starting and finishing each ad break with a broadcaster ident/logo that effectively buys you time while the television/STB is switching between the broadcast signal and IP stream.
He pitched the idea of lining up a fully prepared replacement ad break on the server side, too. This would require that the IP ads being served to the home are chosen slightly earlier. And even if you wanted the household to see a couple of the ‘original’ broadcast ads you would have to make these same ads available on the digital ad server (since the full broadcast ad break is going to be replaced, and not just individual ads within it).
The chief merit of the fully prepared replacement ad break is that you have only two stream switches – into the (new IP) break and then out of the (IP) break and back to the broadcast signal.
Siotis at SpotX pointed out that HbbTV 1.5 can be used today to fully replace broadcast ads at scale. “What is missing is some features that improve the experience, like pre-loading.” His company provides a ‘Get out of jail free’ card when it comes to the ad insertion user experience, anyway.
“To ensure the user experience is as smooth as possible, we check the bandwidth and the device in advance of serving ads. Our ad server makes a judgement call on whether we feel a television set is capable of running the video and maintaining the user experience a broadcaster expects. If it is decided that a suitable UX is not possible, we ignore the opportunity for an ad impression.”
The ‘load stream’ signal from the broadcast is the cue to instigate the health check. This check would apply to any kind of ad (graphical or full video) on any of the HbbTV specification versions.
RTL still needs convincing that full ad replacement can be deployed commercially across the current device footprint. The broadcaster uses HbbTV for graphical ad insertion but as you can read in a separate story, Henry Rivero, VP Advanced Advertising & Innovation at RTL Group, has concerns about the UX and the consistency of devices across markets when it comes to full ad replacement. For full ad replacement, HbbTV is viewed as a test-and-learn process today at RTL. “The ad replacement is what we need to work on next with the standard,” Rivero told the webcast audience.
As more features are introduced to the specification, the danger is that a larger experience gap develops between devices that support the latest spec and those that support ‘only’ v1.5. Rivero at RTL highlighted the need to achieve consistency across devices for at least a minimum performance threshold that he, as a broadcaster, can rely upon for large-scale commercial use.
“It is important to be able to sign off device families and say, ‘We know for sure that they adhere to not only the standards implementation but to the necessary performance requirements’.
“One area that [the HbbTV] specifications have not really touched upon, up to now, is the notion of minimum requirements when we talk about capabilities like buffering and switching,” Rivero continued. “These features are specified but there is no indication about the minimum buffering or switching performance that is necessary.”
Hernes agreed that minimum performance guarantees would enable broadcasters to trust in the UX outcome in each home, and he noted that the HbbTV community is discussing how this can be achieved. The challenge, of course, is that CPU power and RAM cost money. “Low-end TVs will always have less RAM and will switch more slowly than high-end TVs,” he pointed out.
A trade-off will be needed where the minimums are set reasonably high but not so high that they prevent manufacturers of cheaper TVs from participating in the higher specification end the HbbTV market.
Hernes highlighted an alternative approach that could raise standards even higher, at all ends of the device market. “That would need a way to channel money back [from the broadcasting and ultimately advertising industries that benefit from the ad replacement and targeting] to manufacturers. Then there is a business incentive to implement this [the higher specs with higher minimum performance guarantees].”
The webcast highlighted one other potential approach to improving the user experience for IP-into-broadcast content substitution (and therefore ad replacement). Hernes noted how the BBC (whose interest in HbbTV has nothing to do with advertising, and is driven by the possibilities for more personalised content, like regional news feeds) has demonstrated the ability to split the video and audio streams so the replacement (IP-delivered) audio can start playing ahead of the replacement (IP-delivered) video. There is a belief that hearing audio leaves consumers with the impression that the video began earlier.
Audio/video splitting requires HbbTV 2.0.1 and the synchronised broadcast/broadband timing that comes with it. With frame accuracy established, you can start playing the audio from the IP-inserted stream and then add the IP video when it arrives, slightly later. The audio and video are perfectly synchronised once united. Vewd and the BBC demonstrated this innovation at IBC 2018.
For IP-into-broadcast ad insertion, HbbTV is the only viable solution that can deliver scale in Europe. That is the view of Hernes, who urged broadcasters to get behind this standards-driven approach. This webcast laid out the roadmap to HbbTV-enabled addressable TV advertising and the challenges ahead. You can listen to the discussion in full (free) via this link.