MPEG-DASH Gains Toehold In European OTT Distribution

Steve Christian, VP, marketing, Verimatrix

Steve Christian, VP, marketing, Verimatrix

October 2, 2012 – With ever more vendors supporting MPEG-DASH in their encoders, streaming software, DRM platforms and other products, it appears that the standard has found an early beachhead for commercial implementation in Europe.

Multiscreen service distribution via MPEG-DASH (Dynamic Adaptive Streaming over HTTP) is now possible on the cloud-based OTT service that Spain’s Abertis Telecom and NAGRA are offering to European service providers and broadcasters. This addition to the adaptive streaming (AS) formats already available on the cloud service comes in conjunction with integration of NAGRA’s content protection platform with the ProMedia transcoding system supplied by Harmonic.

“By launching the world’s first OTT service supporting MPEG-DASH, Abertis Telecom and NAGRA are breaking new ground and helping to build the future of multiscreen delivery,” says Thierry Fautier, senior director for convergence solutions at Harmonic. He notes this follows Harmonic’s and other vendors’ participation in the first live public MPEG-DASH trial at the London Olympic Games with Belgium broadcaster VRT.

Together these developments highlight the role European broadcasters are likely to play in building early commercial momentum for MPEG-DASH, thanks to adoption of a new multiscreen streaming version of HbbTV (Hybrid Broadcast Broadband TV). This is the standard which, in its first iteration, supported distribution of premium and free Internet content over broadband connections to smart TVs and hybrid set-tops in combination with over-the-air digital terrestrial TV (DTT).

In the two years since HbbTV was finalized broadcasters in growing numbers have been seizing on the OTT opportunity in response to the rising penetration of smart TVs and HbbTV compatible DTT receivers. By 2014 60 million TV sets in Western Europe, representing half the installed market, will be HbbTV compliant, according to the HbbTV Consortium.

This TV-centric foundation for OTT distribution sets the stage for a move to multiscreen streaming in conjunction with the newly released version 1.5 of HbbTV, which includes support for MPEG-DASH. Notably, the partners in the Abertis-NAGRA Multiscreen Cloud Service report that ten free-to-air broadcasters across Europe are in trials with the new DASH implementation.

Demand for the multiscreen extension of HbbTV is strong, says HbbTV Consortium chairman Klaus Illgner-Fehns. “The publication of version 1.5 of the HbbTV specification responds to strong market demand for new features to be included as soon as possible,” he says. “We are already working towards version 2.0 of the specification.”

Another source of momentum from the content side is Netflix, which, according to Mark Watson, director of streaming standards, has made all its media files compliant with MPEG-DASH. Explaining Netflix’ thinking in a post to the DASH Promoters Group, Watson says this means “the majority of our traffic (and so a sizable chunk of U.S. peak Internet traffic) is compliant to the new MPEG-DASH and Common Encryption file format. We hope more and more devices will choose to support these formats.”

Challenges to Market Adoption

These and other efforts to drive DASH into the mainstream face a formidable array of challenges, starting with Apple’s failure to embrace the standard and extending to the chicken-and-egg conundrum where the absence of a DASH-compliant base of client software in IP devices feeds the reluctance of content suppliers to support DASH in their streaming operations. There are also concerns about licensing costs.

While ISO standardization requires that contributors of IP-based intellectual property agree to reasonable licensing terms, it’s unclear what the terms will be on some aspects of the standard. So far, three major players, Microsoft, Qualcomm and Cisco Systems, have agreed to offer their contributions to DASH royalty free.

Royalty issues also dog the encoding arena. DASH is codec agnostic, but H.264 is the predominant mode in use today, and royalty costs there have become an issue, prompting Google’s WebM royalty-free encoding initiative.

The good news is the combination of industry vendor support and proofs of concept in early demonstrations and trials is starting to move the market, says Steven Christian, vice president of marketing at Verimatrix, a key supporter of content protection on DASH. “In my opinion the DASH format will naturally be the center of things in two to three years’ time,” Christian says.

“But in the meantime,” he adds, “there are a lot of existing devices out there to be supported by today’s streaming platforms. So I think we’ll end up with a multi-format delivery system where DASH plays an increasing role over time.”

DASH Goals

DASH addresses the incompatibilities of proprietary AS systems, which employ a “pull” mode in distribution technology that is altogether different from the “push” mode of traditional digital TV. Every few seconds an AS-enabled device, by referencing the bitrate options or “adaptation sets” listed for a given piece of content in a manifest file sent from an HTTP server, asks the server to send a segment fragment of streamed content at the optimum bitrate, depending on how much bandwidth is available at that moment in time and how much processing power the device has available for decoding the bit streams.

The basic goal is to ensure video is streamed at the highest level of quality that can be sustained at any given time without dropping frames or triggering buffering interruptions in the flow. While the proprietary modes, including most prominently Apple’s HTTP Live Streaming (HLS), Microsoft’s Smooth and Adobe’s HTTP Dynamic Streaming (HDS) all use the MPEG-4 H.264 video codec along with MPEG Advanced Audio Coding (AAC), each uses a different approach to constructing fragments, timing their sequence, formatting manifest files and supporting content protection.

DASH aims to overcome these disparities through server-to-client communications which are delivered in an AS manifest file format known as Media Presentation Description (MPD) to define various segments within the stream, each of which is associated with a uniquely referenced HTTP URL. While critics point to the existence of multiple versions of DASH as a reason to doubt its efficacy, in truth, the consensus now is that the market will embrace two versions predicated on two modes of transporting fragments.

These are fragmented MP4 (fMP4) derived from a part of the MPEG-4 standard known as ISO Base Media File Format (BMFF), which is used by Smooth Streaming and HDS, and an approach to fragmentation based on MPEG-2 Transport Stream, which is very close to the proprietary mode used by Apple for HLS. Google’s WebM, which uses another transport mode, appears to be losing steam, as evidenced by Android’s embrace of HLS.

This DASH transport dichotomy isn’t just the result of Apple’s adherence to MPEG-2TS. Many CE manufacturers prefer this choice of transport modes for DASH by virtue of the processing power savings that come with using the same transport that’s used with digital pay TV.

However, one of the attributes of DASH and fMP4 in particular is an intrinsic bridge to MPEG-2TS and HLS whereby the XML-based MPD manifest file is able to present fragments based on the HLS mode of delivery. Thus, DASH-based content formatted for MPEG-2TS will be viewable on any player that conforms to a DASH profile supporting this capability, such as the DASH 264 profile backed by entities comprising the DASH Industry Forum.

The DASH specifications create a standardized means of supporting many other functions as well. These include live streaming as well as progressive download of on-demand content; fast initial startup and seeking; enhanced trick modes and random access capabilities; dual streams for stereoscopic 3D presentations; Multi-view Video Coding used in Blu-ray 3D displays, and, critically, dynamic implementation of diverse protection schemes.

Content Protection

The fact that DASH creates a way to readily communicate to devices what the specific DRM parameters are for a given piece of content overcomes a major cost barrier to scaling connected-device access to premium content. Today, a content supplier who wants to provide a greater level of security than is natively supported on any given AS platform must take specific steps to secure each targeted device with the appropriate DRM client. DASH allows any DASH-compliant DRM to be implemented automatically with no need for intervention by the content supplier.

Verimatrix, for example, has brought support for the DASH Common Encryption format into the domain of its Video Content Authority System (VCAS), which is a harmonized rights management platform designed to streamline delivery of protection to all types of devices, including iOS, Android, PCs, game consoles, smart TVs and set-top boxes. VCAS for DASH, which was demonstrated at the IBC conference in conjunction with Envivio’s encoding platform, complements the support for PlayReady-protected Smooth Streaming already incorporated into VCAS as well as security enhancements to HLS provided through VCAS ViewRight Web components, Christian notes.

“What we’ve tried to offer is a way to deal with the extra complexity of delivering secured content to multiple types of devices through our multi-rights approach,” he says. “VCAS for DASH is a natural part of the overall strategy.”

What this means for devices already running VCAS, such as smart TVs from Samsung and LTG and set-tops from a variety of vendors, is manufacturers have a ready means of introducing support for DASH on the DRM side with a simple software upgrade. “These suppliers have integrated our client-side technology in such a way that they could easily transition to DASH if they want to take that step,” Christian says.

Overcoming Incompatibilities

Of course, all these DASH capabilities are moot if the client doesn’t support the MPD manifest, which is where Apple’s resistance to DASH comes into play as a way to maintain a proprietary link between its devices and the content it provides. But even here there are ways to break through the incompatibilities, if providers are willing to incur some added expenses at the network edges in exchange for savings attained through uniform use of DASH to stream content to all devices.

This is part of what the Belgium VRT trial was all about. Working in cooperation with the DASH Promoters Group and the European Broadcasting Union, the broadcaster delivered OTT coverage of live Olympics events using only DASH, which meant it had to come up with a way to enable access on any devices not running MPD in their AS players.

“The logical flow of online distribution based on MPEG-DASH is very similar to what is currently deployed in adaptive streaming systems,” VRT says in a paper describing the trial. “One needs only an encoded/packaged stream and an HTTP server to get the job done and play out video to a player that supports MPEG-DASH natively.”

VRT explains how this part of the trial was executed: “The simple part of the workflow is demonstrated by the chain starting with the Elemental Live encoder from Elemental Technologies, which captures the audiovisual content from the SDI feed at the VRT premises. The Apache server located at the CDN of Belgacom picks up the data packages via HTTP GET from the encoder and makes it available by a URL and an MPD file describing how the packages should be interpreted by the player. The Adobe player reads out the MPD, buffers the packages and plays out the video on a device of the end user.”
But the Adobe player only worked on PCs and older Android devices, leaving VRT to create another distribution chain to support iOS and newer Android devices running HLS. In this case, the IP feeds of the DASH-streamed live Olympics content were captured, transcoded and packaged just like any other streamed content via Harmonic’s ProMedia Live encoder and transmitted to an origin server at VRT’s premises, where streaming media software supplied by Wowza performed fragmentation and other streaming functions.
To get the streamed content to the targeted devices required that the streams be captured by a Wowza cache server in the CDN, where they were formatted to the HLS transport and manifest templates in conjunction with the appropriate DRMs. “It gets more complicated when one involves dedicated applications that play out video to devices that do not yet support MPEG-DASH natively,” VRT says.

To round out the DASH proof of concept in its trial VRT worked with suppliers to show how DASH Common Encryption works with multiple DRMs in streams that were switched seamlessly between protected and unprotected content. Along with DRM support in the workflows for DASH-ready and non-DASH clients, the trial participants set up another distribution chain to show Common Encryption support for Microsite’s PlayReady DRM.

New Momentum

The VRT trial was meant to show how an application, in this case the Olympics live OTT coverage, could be delivered through DASH to users on all devices. But the more common approach to introducing DASH will be instances where content providers stream a given program using DASH alongside content formatted for the proprietary streaming platforms running on devices that haven’t been made DASH compliant. While, as DASH detractors note, this has the effect of adding still another streaming format to the stack, it also means that as DASH-ready CE devices come to market they can utilize the many benefits of the DASH manifest and multiple-DRM support system with any content and apps that have been positioned to run over DASH.

With the transition last month of the DASH Promoters Group to the more formal DASH Industry Forum, interoperability testing beyond the ad hoc trade show demos and market trials of recent months has become part of the DASH 264 agenda. Over 50 companies now belong to DASH-IF, including founding members Akamai, Ericsson, Microsoft, Netflix, Qualcomm and Samsung.

As interoperability testing unfolds the pace of real-world implementation will depend on how fast the content/device chicken-and-egg barrier is crossed. As Christian notes, smart TV manufacturers have an especially strong interest in getting DASH embedded in their products. “What we’re seeing is the rollout of DASH services will probably start to happen on devices like smart TVs,” he says.

In part, this is because smart TV manufacturers, with an incentive to build consumers’ content experience on their platforms, want to encourage content suppliers to take advantage of all the service types and feature extensions that are enabled through the DASH MDP in a uniform way that broadens participation to the greatest extent possible.

And there’s also an incentive owing to the fact that smart TVs have a longer life cycle than portable devices, which means DASH needs to be there when the market moves in that direction. The upshot is that initiatives along these lines could break the chicken-and-egg syndrome, where, owing to the presence of DASH on smart TVs or set-tops, content suppliers begin to have an incentive to add DASH to their streaming profiles.

This is exactly what’s happening with implementation of the aforementioned HbbTV 1.5 in Europe. HbbTV was a focus of many DASH-based demos at IBC, including one featuring time-shifted service staged by AuthenTec (applications for Android and iOS); Adobe (Flash player supporting MPEG-DASH); CodeShop (Unified Streaming Server); DekTec (DVB modulator); Elemental Technologies (encoding); and LG, which introduced the first connected TV prototype supporting HbbTV 1.5 with MPEG-DASH profiles.

Many other firsts involving DASH were on display at IBC, including the industry’s first MPEG-DASH-based live and on-demand video ad-insertion solution from SeaWell Networks, Inc., another member of DASH-IF. The ad-insertion capability was part of SeaWell’s integration of DASH into its library of supported formats, which include Smooth, HLS and HDS.

Using SeaWell’s Spectrum software, network operators are now able to convert all formats dynamically, and deliver IP video content to any connected device, notes Brian Stevenson, director of product management at SeaWell. “With the integration of the international DASH industry standard, Spectrum enables operators to not only store and deliver content in any format, but to now insert advertising seamlessly into the live or VOD stream. This is a market first.”

In another instance of new initiatives unveiled at IBC, Digital Rapids says upcoming new solutions in its product portfolio powered by its Kayak workflow technology platform will support DASH, including version 2.0 of the Digital Rapids Transcode Manager high-volume media processing software and the StreamZ Live Broadcast integrated broadcast/multiscreen live encoder. Notwithstanding all the confusion in the marketplace and efforts by some players, including network service providers, to devise their own solutions to incompatibility and other streaming deficiencies, there’s an inevitability about DASH, as well as the UltraViolet electronic sell-through standard, which are increasingly linked in standards development, says Brick Eksten, co-founder and president of Digital Rapids.

“We started working with people who were thinking about DASH before there was a real group promoting the standard,” Ecksten says, noting there was great interest among CE manufacturers in finding a way out of the adaptive streaming weeds. “While all the various operators out there are building defensive positions with players that offer multiscreen solutions, the market momentum is toward standardization.”