MPEG-DASH: Why it Matters, Where it Goes From Here
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 synchronisation,” he says, “[i]t 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 point[s] to DASH being the great unifier,” warns AmberFin Ltd. 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, Inc.’s 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, LLC, 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: “[I]ssues 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, Inc. 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 operationalising 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 centring on the use of MPEG-DASH as a primary distribution format from centralised 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 commercialisation -- 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 rationalisation 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.”
This article appeared in the autumn 2013 Streaming Media European Edition as "DASHing to the Future."
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