Moving pictures

Video is expected to dominate mobile traffic in the years ahead. But much still needs to be done to ensure a seamless video experience over mobile networks. Anna Tobin reports.

The demand for video on mobile screens is at an all time high and it is yet to peak. According to a Nokia Bell Labs mobility traffic report, mobile video streaming will represent 79% of all mobile data traffic by 2020.

Although users have often come to expect slow start times due to buffering and disruptions in service, the smartphone is already often the first screen of choice for consuming video for the younger generation. And for people in much of the developing world, it’s the only available screen.

This presents two challenges for content creators and distributors: they must iron out those quality problems and they must ensure that their content can be viewed anywhere, at anytime, efficiently and economically. Consumers will increasingly demand reductions in data consumption charges or expect near universal broadband/WiFi access. If operators are to thrive under these conditions they will need to adapt their business models too.

LTE technology

What was a very narrow geographical target area for distributing mobile content is now getting much wider as a result of developments in LTE broadcast or eMBMS technology. This has been a game changer for the industry, according to Roland Mestric, director of marketing for Nokia’s IP video business: “LTE broadcast deployments have focused on delivering media content to contained locations, such as stadiums and concert halls, often limited to the duration of an event. Nokia, however, has shown that eMBMS can be used to cover a much larger area,” he says. “Single Frequency Networks [SFN] technology has been tested over a large footprint to prepare for wide area TV coverage up to nationwide networks. With SFN, all base stations use exactly the same frequency to transmit TV content, which maximises the number of simultaneous TV channels broadcast over a large geographical area in a given amount of spectrum. The technology holds promising new business opportunities for mobile operators to distribute TV over their LTE mobile broadband infrastructure. Subscribers will be able to watch TV on their devices without eating into their mobile data plan and independent of network load.”

As LTE broadcast becomes scalable, with an LTE/eMBMS-enabled device it will be possible to receive content delivered over a multicast stream. The problem is that not all devices support eMBMS. Samsung is on board, but Apple has yet to implement the technology, which cuts out a substantial chunk of the market.

It does have a growing fan base though, says Michael Archer, chief strategist, mobile technologies at CDN giant Akamai: “An ecosystem of support has gradually built up around the technology, including major network operators and network vendors, to the point where the technology now has the base to attract investment and take off. The investment case has also been improved by the emergence of additional use cases on top of video streaming, such as delivery of OTA software updates,” he says.

With growing demand for highly personalised content, particularly when it comes to revenue boosting fully-targeted adverts, some mobile operators are concentrating on enhancing the unicast experience, optimising the bandwidth in their core network and monetising adaptive bitrate (ABR) and HTTP-based video streams.

But for linear TV, ABR has a fundamental scaling disadvantage, with a requirement for an exponential growth in the amount of bandwidth required when compared to broadcast LTE, says Mestric at Nokia. However, he adds that there are a number of tools in the operator’s arsenal that can go a long way to alleviating some of these issues: “Dynamic rate shaping and bitrate throttling allow an operator to deliver ABR manifests where the bitrate and resolution are more suited to network saturation and device characteristics,” he explains. “Re-fragmentation can adapt ABR fragments to make them more suitable for the loss and latencies expected on mobile networks and conditional encoding provides the ability to re-encode content at lower rates that vary as a function of video complexity and network saturation.”

Currently, the most efficient way of delivering mobile video depends very much on what your use case and business model is, says Archer at Akamai: “If you’re a subscription viewing company with a library of box-sets to stream to viewers, for example, in today’s market unicast is almost always going to be the obvious solution. If you’re looking at live video – such as sporting events – LTE broadcast is currently going to be best for that content,” he says. “If a company is quadplay and owns the content and the infrastructure, the economic model changes and, again, LTE broadcast is probably the better option for live delivery.”

Universal WiFi

Interestingly, while mobile video technology has been developing, user behaviour has been changing too and this is not necessarily in a way that exactly matches the evolution of technological possibilities. This has led to an interesting paradox, says Simon Trudelle, senior director of product marketing at Nagra.

“While video consumption on mobile devices outside the home is on the rise, a lot of that consumption comes from short-form video or it is done offline, as various physical constraints – from steel beams in buildings to subway tunnels or fast-moving cars and trains – make stable and reliable 4G video network access challenging at best, or simply not possible in many mobility situations,” says Trudelle. “In parallel, subscribers also want personalised replay video access even when at stadiums, transportation hubs and open-air live events, where the concentration of 10, 20 or 50,000-plus devices connecting to an on-demand service puts severe stress on mobile infrastructure or pushes up costs too high. Industrial WiFi solutions have been emerging as an alternative solution for these specific use cases.”

Even though LTE broadcast technology makes large-scale consumption possible, most long-form mobile video is currently watched via WiFi networks or it’s downloaded to be watched later on the go.

“Mobile networks are already seeing a good deal of video streaming usage, enabled by the higher data rates of 4G networks,” says Archer at Akamai. “It’s less common for pre-recorded content such as TV programmes and films to be streamed over mobile networks. One of the key reasons for this is that data consumption, if you don’t have an all-you-can-eat bundle, is far more expensive over a mobile network than over a fixed-line or WiFi.”

With strong competition in the market leading to mobile data prices falling and the creation of unlimited packages, cellular streaming could see an upsurge in popularity in the near future, but until that coverage is more or less universal it will remain lacking in reliability. And unless the distribution costs fall this business model won’t be sustainable for operators in the long term either.

The realisation that the appetite for long-form content on the move isn’t there –because the quality isn’t up to scratch and because consuming video in this way gobbles up expensive data – has also led service and content providers to look at pushing new content formats. They are trying to move into short-form content provision, says Trudelle at Nagra: “It’s clear that innovative service providers are now looking at ways to provide short-form content better suited to the mobile on-the-go experience and fight for ‘mobile eye share’, keeping subscribers on their service throughout the day, instead of seeing them consume video on platforms like YouTube and Facebook,” he says. “Powering these new video services requires more flexible back-end platforms that can address multiple consumer profiles, over multiple delivery networks. Such use cases were taken into account in the design of our OpenTV Signature Edition platform announced at IBC 2017.”

The 5G future

As 5G becomes a mainstream mobile technology it holds out the possibility of revolutionising mobile and, through 5G fixed wireless access (FWA), home-based media consumption too. 5G could provide faster and higher bit-rate streaming and enhanced quality, delivering data rates of tens of megabytes to tens of thousands of viewers with microsecond latency. “It will enable seamless delivery of highly personalised unicast content delivery, while paving the way for Ultra HD and 360°/VR viewing on mobile devices and video enabled CE devices that leverage FWA in the home,” predicts Mestric at Nokia.

5G will open up innovative revenue streams too, says Christopher Mueller, CTO and co-founder of Bitmovin: “The traditional telcos are having to adapt their business models. They have to invest in the infrastructure and in mobile broadband technology in general to keep up with the pace of change,” he says.

There is, however, the possibility of a geographical rift opening up, driven by quality of service and 5G reach in urban and rural areas, suggests Trudelle at Nagra: “Mobile operators are entering a new phase of the market where the battle is for geographical 4G/5G coverage and overall quality of service for video streaming. Insufficient reach and/or video quality will lead to subscriber churn and more so in remote areas,” he says. “For subscribers living in urban areas, where Wi-Fi is the pre-dominant way of accessing video services, mobile bandwidth and QoS are less of an issue. So differentiation going forward may actually be on price and service bundling. Some traditional pay TV providers may find an opportunity to become MVNOs or partner with telcos to create content and network bundles and strengthen their subscriber relationships, while adding a revenue-generating unit to their business model…The impact of 5G networks on the content industry will be positive overall, yet it has to be seen as an incremental opportunity to increase reach, more than a revolution that would send other network technologies to the recycling bin.”

Video is already the largest consumer of data on the average smartphone. This would seem to make it a priority for standardisation, but progress has been slow in this area. Things are beginning to change, however, says Archer at Akamai.

“One area where broadcasters are getting involved in the conversation is through 5G-Xcast – a project bringing broadcasters together to analyse the requirements for future technologies, ranging from UHDTV to mixed reality and to scope the technical specifications needed to deliver them,” he explains. “In developing media delivery solutions, the project aims to take account of the wider use ranges of 5G, including services to vehicles, public safety and health and the Internet of Things to ensure that they dovetail together. However, examples of this collaboration are too few and far between and there is currently no agreed standard for 5G deployments. The biggest issue will be getting mobile operators and broadcasters to agree to build one ecosystem that works everywhere and for everyone. There are not enough broadcasters getting involved in setting the standards and more of them should be talking to their MNO partners to establish better ways to work together.”

In order for 5G to take the baton from 4G, a near universal standard or group of standards needs to be agreed.

New video standards are needed to make 5G video consumption grow and they will happen, says Mestric at Nokia: “New video standards and processing techniques will bring even more scale. Fast Start and Low Lag based on ‘chunk encoding’ and CMAF provide ultra-low latency, ensuring that the mobile stream is in sync with the broadcast feed, so each viewer enjoys a goal at the same time, regardless of the content source,” he says. “In anticipation of 5G video streaming, organisations including the Stream Video Alliance and 5G Americas are already defining recommendations and best practice-related mobile delivery and addressing subjects as diverse as scalability, quality of experience, geo-fencing for licensed content and service protection for streaming media.”

As history has shown for every mobile technology that has come before it, 5G standards will eventually emerge, but the technology may be stalled in the meantime. While the waiting game is played out, consumers will continue to use a mix of delivery systems involving live play and download to enhance their experience of watching video on the move.