Mobile viewing: refining delivery workflows is making it easier to provide consistent experiences

If you were looking to compile a roll call of industries that appear bulletproof regardless of the economic circumstances of the time, it’s very likely that the mobile sector would reside near the top of the list. For example, even during the profound uncertainty of the past 12 months, sales of smartphones have continued to skyrocket, with the International Data Corporation (IDC) recently forecasting smartphone shipments to grow 13.9% year over year in Q1 2021, and 5.5% for full year 2021.

As Harmonic’s vice president, video strategy Thierry Fautier remarks, it’s important to “make a distinction between mobile consumption and the mobile network – an estimated 80% of mobile traffic is on WiFi”. But, as a significant minority of soaring mobile traffic that is expected to reach 226EB per month in 2026 (source: Ericsson), this doesn’t negate the fact that the main challenges attached to on-the-move viewing – namely, the ability to view content with as little interruption or degradation of quality as possible – have become more acute.

Broadpeak business development director Yann Begassat acknowledges that mobile video has “made a lot of progress over the last few years”, but it remains a moving target. “While users in the past were less demanding when it comes to video streaming quality of experience (QoE) on their smartphones versus the big screen, they have much higher expectations today now that they are consuming increasingly more video content on their mobile device,” he explains.

“There is still plenty of room for improvement when it comes to watching live TV on a mobile device through a cellular network. For example, rebuffering remains a very common issue, not to mention the 30 to 45 seconds of latency that can be experienced over live video streams – a real pain for viewers, particularly those watching live sports events.”

Hence, along with a focus on further refinement of the apps used to deliver an increasing amount of content, there is a strong emphasis on content delivery network (CDN) quality – and, in particular, the adoption of multi-CDN strategies to reduce the risk of negative impact on services.

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Mobile first, mobile always
On its website, Verizon Media – whose Media Platform has been adopted by traditional linear and OTT broadcasters worldwide – observes that consumers “expect the same consistent experience” however they are viewing content. For Darren Lepke, Verizon Media’s head of video product management, that aspiration is increasingly within reach of mobile device users.

“Whereas there were once different platforms to address, there are now two main ones to deliver for - Android and iOS,” he says. “There is also a trend towards mobiles as the primary vehicle, rather than it be between mobiles and tablets, with [content services] adopting a strategy of ‘mobile first’ and sometimes ‘mobile always’. As long as you are adaptive, the tablets will follow on anyway.”

To reach the current phase where we have “never seen better QoE and QoS [quality of service], there have been several primary enabling factors, adds Lepke: “CDNs are maturing in terms of their deployment, their performance and their availability to different services – in other words, the network infrastructure side is doing well. Also, we are seeing some stabilisation around video codecs – in particular H.264 and H.265 – which is allowing [more concentrated] investments to be made, as a result of which there is a continuing increase in video quality.”

“CDNs are maturing in terms of their deployment, their performance and their availability to different services,” Darren Lepke, Verizon

Looking ahead, he expects that content delivery will be aided by increased convergence between “what used to be a separate broadcast silo and a ‘digital’ silo, as people recognise that it’s a content business now”. Increasingly, where “bottlenecks do still occur, it is largely out of the video workflow and content delivery pieces – and more to do with aspects like authentication services and payment servers”.

Simpler systems, better experiences
Fast-evolving HTTP-based protocols are in the process of transforming mobile viewing, says Begassat, who goes on to pinpoint two specific examples: the evolution of HLS to support CMAF and LL-HLS, now supported by all recent iOS devices; and the emerging unification of DASH and HLS, using CBCS. This trend, he continues, “translates to simpler systems and better experiences for the end-users, with fewer variants leading to higher caching efficiency”.

In terms of Broadpeak’s own developments in this area, Begassat highlights an approach to multi-CDN that brings the possibility of “making CDN selection not only at the start, but also all along the duration of a video session, directly in the terminal that plays the content”. This technology, known as CDN Diversity, “allows connection to multiple CDNs in parallel to ensure maximum throughput, depending on real-time conditions. It’s also multiple-TCP – similar to what Netflix does to ensure maximum throughput during video sessions, with the client actually connecting to several Netflix caches in parallel.”

In keeping with Begassat’s observation that collecting and reporting QoE metrics is fundamental to maintaining effective content delivery via app, Broadpeak also brings its SmartLib agent into the video client – SmartLib being an embedded application that can provide Broadpeak’s analytics platform with extensive data. “This is key to retrieving reliable and fine QoE client metrics in real-time such as start-time, rebuffering, latency and so on,” he says. “This allows the user experience to be tracked and optimised and is also necessary for integration into ad workflows to justify ads that have already been seen by the user.”

• Read more: How CDN providers are meeting OTT-fuelled demand 

Differences of experience
Harmonic’s Fautier cites a recent Sandvine report that indicates 65% of mobile traffic is now represented by video (https://www.sandvine.com/inthenews/video-over-65-percent-mobile-traffic). Nonetheless, content viewing experiences are still the subject of variation, with there being “a difference of experience between free content where traffic is much higher and therefore quality can be degraded, versus a paid service where the user expects better QoE. Meanwhile, consumers are frustrated with their mobile streaming experience at peak traffic times (ie, when they are taking public transportation) and are now downloading the content, which is a standard feature on Netflix [via an app] and a paid feature on YouTube.”

He pinpoints three courses of action as being integral to the delivery of a consistent experience across devices, including a profile setting that is optimised for mobile viewing and “allowing no more than 1080p resolution”; a good CDN solution that can cover mobile network usage; and the use of “content-aware encoding with AVC to reduce traffic and increase QoE, and also with HEVC for enabled mobile devices”. Like many other observers, Fautier also thinks that 5G – which will enable 1080p to all users at a minimum – has huge potential, not least within large sports venues.

“With 5G we can expect to deliver a decent video experience to 100,000 people within stadiums,” Thierry Fautier, Harmonic

“Mobile video traffic will increase with the deployment of 5G, and as the network has more capacity we expect to see additional concurrency with higher bitrates per session,” he says. “One of the use cases poorly covered by 4G is in-stadium experiences. With 5G we can expect to deliver a decent video experience to 100,000 people within stadiums. 5G will also enable the development of more immersive experiences with 8K, VR and video point cloud, all of which are supported by 5G phones.”

The sense of mobile content consumption approaching a new and exciting phase of development is unmistakable. With network technology progressing and vendors going through an extraordinary period of advancement, it’s clear that the ideal of a superb and seamless experience across devices is closer than ever before.