The need to reach multiple platforms and consumer electronics devices has long presented a technical and business headache, not to mention a cost for service providers looking to deliver online video. the holy grail of a common file format that would rule them all always seemed a quest too far.
Enter MPEG-DASH, a technology with the scope to significantly improve the way content is delivered to any device by cutting complexity and providing a common ecosystem of content and services.
The MPEG-DASH standard was ratified in December 2011 and tested in 2012, with deployments across the world now underway. Yet just as MPEG-DASH is poised to become a universal point for interoperable OTT delivery comes concern that slower-than-expected initial uptake will dampen wider adoption.
A Brief History of DASH
The early days of video streaming, reaching back to the mid-1990s, were characterized by battles between the different technologies of RealNetworks, Microsoft, and then Adobe. By the mid-2000s, the vast majority of internet traffic was HTTP-based, and Content Delivery Networks (CDNs) were increasingly being used to ensure delivery of popular content to large audiences.
“[The] hodgepodge of proprietary protocols -- all mostly based on the far less popular UDP -- suddenly found itself struggling to keep up with demand,” explains Alex Zambelli, formerly of Microsoft and now principal video specialist for iStreamPlanet, in his succinct review of the streaming media timeline for The Guardian.
That changed in 2007 when Move Networks introduced HTTP-based adaptive streaming, adjusting the quality of a video stream according to the user’s bandwidth and CPU capacity.
“Instead of relying on proprietary streaming protocols and leaving users at the mercy of the internet bandwidth gods, Move Networks used the dominant HTTP protocol to deliver media in small file chunks while using the player application to monitor download speeds and request chunks of varying quality (size) in response to changing network conditions,” explains Zambelli in the article. “The technology had a huge impact because it allowed streaming media to be distributed ... using CDNs (over standard HTTP) and cached for efficiency, while at the same time eliminating annoying buffering and connectivity issues for customers.”
Other HTTP-based adaptive streaming solutions followed: Microsoft launched Smooth Streaming in 2008, Apple debuted HTTP Live Streaming (HLS) for delivery to iOS devices a year later, and Adobe joined the party in 2010 with HTTP Dynamic Streaming (HDS).
HTTP-based adaptive streaming quickly became the weapon of choice for high-profile live streaming events from the Vancouver Winter Olympics 2010 to Felix Baumgartner’s record breaking 2012 Red Bull Stratos jump (watched live online by 8 million people).
These and other competing protocols created fresh market fragmentation in tandem with multiple DRM providers and encryption systems, all of which contributed to a barrier to further growth of the online video ecosystem.
In 2009, efforts began among telecommunications group 3rd Generation Partnership Project (3GPP) to establish an industry standard for adaptive streaming. More than 50 companies were involved -- Microsoft, Netflix, and Adobe included -- and the effort was coordinated at ISO level with other industry organizations such as studio-backed digital locker initiator Digital Entertainment Content Ecosystem (DECE), OIPF, and World Wide Web Consortium (W3C).
MPEG Dynamic Adaptive Streaming over HTTP (MPEG-DASH, or DASH for short) was ratified as an international standard late in 2011. It was published as ISO/IEC 23009-1 the following April and was immediately heralded as a breakthrough because of its potential to embrace and replace existing proprietary ABR technologies and its ability to run on any device.
At the time, Thierry Fautier, senior director of convergence solutions at Harmonic, said the agreement on a single protocol would decrease the cost of production, encoding, storage, and transport: “This is why everyone is craving to have DASH. It will enable content providers, operator and vendors to scale their OTT business,” he told CSI magazine in February 2012.
In the same article, Jean-Marc Racine, managing partner at Farncombe, said, “By enabling operators to encode and store content only once, [DASH] will reduce the cost of offering content on multiple devices. Combined with Common Encryption (CENC), DASH opens the door for use with multiple DRMs, further optimising the cost of operating an OTT platform.”
The Benefits of DASH
The technical and commercial benefits outlined for MPEG-DASH on launch included the following:
- It decouples the technical issues of delivery formats and video compression from the more typically proprietary issues of a protection regime. No longer does the technology of delivery have to develop in lockstep with the release cycle of a presentation engine or security vendor.
- It is not blue sky technology -- the standard acknowledged adoption of existing commercial offerings in its profiles and was designed to represent a superset of all existing solutions.
- It represented a drive for a vendor-neutral, single-delivery protocol to reduce balkanization of streaming support in CE devices. This would reduce technical headaches and transcoding costs. It meant content publishers could generate a single set of files for encoding and streaming that should be compatible with as many devices as possible from mobile to OTT, and also to the desktop via plug-ins or HTML5; in addition, it meant consumers would not have to worry about whether their devices would be able to play the content they want to watch.
“DASH offers the potential to open up the universe of multi-network, multi-screen and multi-operator delivery, beyond proprietary content silos,” forecast Steve Christian, VP of marketing at Verimatrix. “In combination with a robust protection mechanism, a whole new generation of premium services are likely to become available in the market.”
Perhaps the biggest plus was that unlike previous attempts to create a truly interoperable file format, without exception all the major players participated in its development. Microsoft, Adobe, and Apple -- as well as Netflix; Qualcomm; and Cisco -- were integral to the DASH working group.
These companies, minus Apple, formed a DASH Promoters Group (DASH-PG), which eventually boasted nearly 60 members and would be formalized as the DASH Industry Forum (DASH-IF), to develop DASH across mobile, broadcast, and internet and to enable interoperability between DASH profiles and connected devices -- exactly what was missing in the legacy adaptive streaming protocols.
The European Broadcasting Union (EBU) was the first broadcast organization to join DASH-IF, helping recommend and adopt DASH in version 1.5 of European hybrid internet-TV platform HbbTV. Other members have since boarded, including France and Spain, which have already begun deploying DASH for connected TVs, with Germany and Italy expected to follow. In the U.S., DASH is attracting mobile operators, such as Verizon, wanting to deploy eMBMS for mobile TV broadcast over LTE.
What about HLS?
However, there remain some flies in the ointment. The format for DASH is similar to Apple’s HLS, using index files and segmented content to stream to a device where the index file indicates the order in which segments are played. But even though representatives from Apple participated in drawing up DASH, Apple is holding fast to HLS and hasn’t yet publicly expressed its support for DASH.
Neither has Google, though it has confirmed that the standard is being tested in Google Chrome. Some believe that until DASH is explicitly backed by these major players, it will struggle to gain traction in the market.
“Right now there are multiple streaming options and until Apple and Google agree on DASH, it will be a while before there is widespread adoption,” says Hiren Hindocha, president and CEO of Digital Nirvana.
Adobe has encouragingly adopted the emerging video standard across its entire range of video streaming, playback, protection, and monetization technologies. Its backing will greatly reduce fragmentation and costs caused by having to support multiple video formats.
“We believe that if we have Microsoft, Adobe, and to some extent Google implementing MPEG-DASH, this will create a critical mass that will open the way to Apple,” says Fautier. “Timing for each of those companies is difficult to predict though.”
While Apple HLS has considerable momentum, other adaptive streaming protocols are being dropped in favor of DASH, which observers such as David Price, head of TV business development for Ericsson, and Brian Kahn, director of product management for Brightcove, reckon will mean that there will only be two mainstream protocols in use for the vast majority of streaming services.
“Since both Adobe and Microsoft have been pushing DASH as a standard, we can assume that HDS and Smooth Streaming will be replaced by DASH helping to reduce the number of formats,” wrote Kahn in a Brightcove blog post. In an email to me, Kahn wrote, “Additionally, Google Canary has a plugin for MPEG-DASH and it is rumoured that Google created the plug-in internally. In the end, we will probably end up with two main streaming formats: HLS and DASH.”
So why doesn’t the industry just adopt HLS instead of adding another streaming protocol? Kahn’s email points to two reasons. “First, it’s not officially a standard -- it’s a specification dictated by Apple, subject to change every six months. It also doesn’t have support for multi-DRM solutions -- DASH does, which is why most major studio houses have given it their endorsement.”
Other Roadblocks to Adoption
But the road to DASH adoption won’t be a straight one. Kahn highlights in particular the challenge of intellectual property and royalties. “This is undoubtedly an issue which will need to be addressed before DASH can achieve widespread adoption,” he told Streaming Media. “DASH participants such as Microsoft and Qualcomm have consented to collate patents for a royalty free solution, but the likes of Adobe have not agreed.
“Mozilla does not include royalty standards in its products, but without the inclusion of its browser, the likelihood of DASH reaching its goal of universal adoption for OTT streaming looks difficult,” Kahn adds. “Another potential obstacle to standardisation is video codecs -- namely, the need for a standard codec for HTML5 video. Even with universal adoption of DASH by HTML5 browsers, content would still need to be encoded in multiple codecs.
Ericsson’s Price also notes some concern about the way in which DASH is being implemented: “In regards to the elements that are discretionary, particularly in the area of time synchronization, it is hoped that as adoption becomes wider, there will be industry consensus on the implementation details; the best practise guidelines being created by DASH-IF will further accelerate adoption.”
There are further warnings that delays in implementing DASH could harm its success as a unifying format. A standards effort necessarily involves compromises, and probably the biggest compromises get hidden in the profile support in the overall standards effort. MPEG-DASH in its original specification arguably tried to be everything to everyone and perhaps suffered from excessive ambiguity (a story familiar to anyone acquainted with HTML5 video, notes Zambelli wryly).
“There are several trials and lots of noise about MPEG-DASH, but we’ve yet to see concrete demand that points to DASH being the great unifier,” warns AmberFin CTO Bruce Devlin. “In fact, unless there is some operational agreement on how to use the standard between different platform operators, then it might become yet another format to support.”
“DASH has taken quite a while to gather a following among consumer electronics and software technology vendors, delaying its adoption,” reports RGB Networks’ senior director of product marketing Nabil Kanaan. “The various profiles defined by DASH have added too much flexibility in the ecosystem, at the cost of quick standardisation. We still believe it’s a viable industry initiative and are supporting it from a network standpoint and working with ecosystem partners to make it a deployable technology.”
Elemental Technologies’ VP of marketing, Keith Wymbs, adds, “To date the impact of MPEG-DASH has been to spur the discussion about the proliferation of streaming technologies.”
“MPEG-DASH isn’t in a position where people are thinking that it will be the only spec they’ll need to support in the near to mid-term,” says Digital Rapids marketing director Mike Nann, “but most believe that it will reduce the number of adaptive streaming specifications that they’ll need to prepare their content for.”
Jamie Sherry, senior product manager at Wowza Media Systems, also thinks DASH has had very little impact to date other than to re-emphasise that for high-quality online video to really become profitable and widespread: “Issues like streaming media format fragmentation must be addressed.
“If the ideals of MPEG-DASH become a reality and traction occurs in terms of deployments, the impact to the market will be positive as operators and content publishers in general will have a real opportunity to grow their audiences while keeping costs in line,” he says.
DASH-AVC/264
To address this, the DASH-IF has been hard at work defining a subset of the standard to serve as a base profile that all implementations have to include. This is driven by the decision to focus on H.264/MPEG-4 encoding rather than MPEG-2 (initially both were supported). The result, DASH-AVC/264, was announced in May and is widely tipped to achieve broad adoption by speeding up the development of common profiles that can be used as the basis for interoperability testing.
“As an analogy, look back at the evolution of MPEG-2 and Transport Streams,” says Nann. “If every cable operator, encoder, middleware vendor, and set-top box vendor supported a different subset of parameters, profiles, levels, and features, they might all be within the MPEG-2 and TS specs, but we probably wouldn’t have the widespread interoperability (and thus adoption) we have today. DASH-AVC/264 is a means of doing the same for MPEG-DASH, providing a constrained set of requirements for supporting DASH across the devices that support it, and giving vendors interoperability targets.”
Aside from requiring support for H.264, the DASH-AVC/264 guidelines define other essential interoperability requirements such as support for the HE-AAC v2 audio codec, ISO base media file format, SMPTE-TT subtitle format, and MPEG Common Encryption for content protection (DRM).
“The Common Encryption element is particularly interesting because it enables competing DRM technologies such as Microsoft PlayReady, Adobe Access, and Widevine to be used inclusively without locking customers into a particular digital store,” writes Zambelli. “DASH-AVC/264 provides the details desperately needed by the industry to adopt MPEG-DASH and is expected to gain significant traction over the next one to two years.”
Digital Rapids’ Nann says he expects to see increased adoption in 2013 with “considerably more pilot projects as well as commercial deployments,” with growing device support (particularly for consumer viewing devices). “The client device support is going to be one of the biggest factors in how quickly MPEG-DASH rolls out,” says Nann.
Telestream product marketing director John Pallett concurs: “The primary driver for adoption will be the player technology to support it. The companies that develop players are generally working to support MPEG-DASH alongside their legacy formats. Most of the major player companies want to migrate to DASH, but real adoption will come when a major consumer product supports DASH natively. This has not yet happened, but we anticipate that it will change over the next year.”
For Peter Maag, CMO of Haivision Network Video, the value proposition is simple: “MPEG-DASH will simplify the delivery challenge if it is ubiquitously embraced. Realistically, there will always be a number of encapsulations and compression technologies required to address every device.”
The number of trials are growing and already include the world’s first large-scale test of MPEG-DASH OTT multiscreen at the 2012 London Olympics with Belgian broadcaster VRT, and the first commercial MPEG-DASH OTT multiscreen service with NAGRA and Abertis Telecom in 2012 -- both powered by Harmonic.
“Over the next years, we believe a significant amount of operators will deploy OTT and multiscreen services based on DASH,” suggests Fautier.
In an interview with Streaming Media, Kevin Towes, senior product manager at Adobe, declared 2012 as the year of DASH awareness and 2013 as the year of discovery.
“How can you attach some of these encoders and CDNs and players and devices together to really demonstrate the resiliency and the vision of what DASH is trying to present?” he said. “And then as we go through that it’s about then operationalizing it, getting DASH into the hands of the consumers from a more viewable point of view.”
Elemental Technologies’ Wymbs believes the discussion will evolve in the next 12 months “to one centering on the use of MPEG-DASH as a primary distribution format from centralized locations to the edge of the network where it will then be repackaged to the destination format as required.”
Given the number of elements of the value chain that need to line up for full commercialization -- encoders, servers, CDNs, security systems, and clients as a minimum -- significant commercial rollouts were always likely to take time.
In conclusion, while there are still hurdles to clear, DASH is clearly on the path toward widespread adoption, especially now that DASH-AVC/264 has been approved. According to contributing editor Tim Siglin: “If there is some form of rationalization between HLS and DASH, including the ability to include Apple’s DRM scheme in the Common Encryption Scheme, we might just note 2013 not only as the beginning of true online video delivery growth but also as the point at which cable and satellite providers begin to pay attention to delivery to all devices -- including set-top boxes -- for a true TV Everywhere experience.”
By Adrian Pennington,
StreamingMedia
