MPEG-DASH: A bold new world for streaming?
MPEG-DASH, the new standard for adaptive streaming, has gotten a lot of attention lately. Does it deserve it? I think so, and here are four reasons why.
1. DASH is an international standard
Since the dawn of streaming media, customers and much of the streaming media ecosystem have had strong dependencies on proprietary solutions from companies such as Apple, Microsoft, and Adobe. Problematically, those industry heavyweights could not always be as agile or responsive to evolving market needs as they or their customers would have liked. Perhaps more challengingly, although many of these traditional streaming products were arguably successful in terms of functionality and market adoption, some were discontinued or put into maintenance mode when internal priorities shifted, leaving customers in a difficult position.
For similar reasons, it has been hard to bet your business in recent years on any one of the newer vendor-centric adaptive streaming formats, such as Apple HTTP Live Streaming (HLS), Adobe HTTP Dynamic Streaming (HDS), or Microsoft Smooth Streaming, over which you have no control: although some specifications have been published for all of these formats, none of them are industry standards. However, using attributes from all three of those formats, a new international standard was created: Moving Picture Experts Group Dynamic Adaptive
Streaming over HTTP, more commonly known as MPEG-DASH or just DASH.
DASH was ratified as a standard in November, 2011, largely due to the concerted technical input and cooperation from dozens of industry-leading broadcast, video, software, hardware, and services organizations, including Adobe, Apple, and Microsoft. Almost all of these, with the notable exception of Apple, became founding members of the DASH Industry Forum (http://dashif.org), which was created to help accelerate DASH adoption. (Wowza is also a founding Contributor Member of the DASH Industry Forum.) The DASH standard was subsequently published as the International Organization for Standardization/ International Electrotechnical Commission (ISO/IEC) 23009-1 standard.
Having an international standard helps eliminate dependencies on vendor-centric formats and increases market confidence in embracing adaptive streaming. To ensure interoperability for industry adoption, the DASH Industry Forum published “DASH-AVC/264 Implementation Guidelines.” The guidelines define specific DASH encoding profiles, codecs (i.e., H.264/AAC), and other key attributes needed to deliver both on-demand and live streaming services. This allows vendors from every part of the video workflow to offer fully interoperable products to their customers.
One caveat: today, Apple requires the use of HLS in all video streaming apps accepted to the App Store. Although Apple contributed to DASH standardization, it has not yet indicated whether it will adopt DASH, or will instead continue refining HLS on its own and requiring it in iOS apps, which would lead us down a bifurcated path of two de facto adaptive streaming standards. Fortunately, as with the existing ability for streaming media servers to easily repackage HDS and Smooth Streaming content into the HLS format, DASH content is similarly backwards-compatible with HLS through repackaging. What does that mean for you? Even in a world awash with iPhones and other HLS playback devices, you will still be able to use a simplified streaming workflow based on MPEG-DASH.
2. DASH has all the features you love
DASH draws from many of the best concepts in the previously-mentioned vendor-centric adaptive streaming formats. Better yet, because DASH is the latest iteration in adaptive streaming, it helps eliminate feature inconsistencies sometimes found across the vendor-centric formats.
As you might expect, DASH provides dynamic adaptive streaming, allowing users on lower-bandwidth connections, fluctuating mobile connections, or older hardware to have the kind of non-stop playback experience that first made adaptive streaming so popular. For premium content providers, DASH features such as ad insertion and a common encryption scheme for content protection will be critical to meeting business requirements. In terms of scaling for delivery, DASH inherits the ability to use existing HTTP caching infrastructures and content delivery networks to easily reach far-flung viewers and scale for the largest audiences.
DASH features also include many capabilities viewers might associate with premium television experiences, such as HD video quality, the ability to pause a live stream or replay the last 15 seconds, surround sound, and multi-language audio. In fact, many broadcasters have been embracing adaptive streaming to deliver TV-like experiences to their subscribers on any device. With consumers increasingly able to enjoy really great experiences on both their traditional TV and on their connected devices, the lines between TV broadcast and streaming video are increasingly blurred.
3. DASH is on TV
Speaking of premium television experiences, DASH is not just emulating those, but is now one of the technologies powering them. Hybrid Broadcast Broadband TV (HbbTV) is a standard for connected TVs and set-top boxes that seamlessly blends delivery of broadcast television with IP-based content delivered over an Internet connection. The goal is to allow users to enjoy rich experiences on their televisions using a single remote to access content such as traditional linear broadcasts, online video services, programming guides, interactive advertising, catch-up TV, video on demand, games, social networking, and more.
A critical aspect to the increasing adoption of HbbTV is that it is based on several existing IPTV, Broadcast, and streaming standards. HbbTV itself was approved by the European Telecommunications Standards Institute (ETSI) as ETSI TS 102 796 in June, 2010. In November, 2012, a new version of the HbbTV standard (HbbTV 1.5) was approved. This update incorporated MPEG-DASH as the designated format for delivering adaptive streaming content to Internet-connected TV devices.
HbbTV is sometimes promoted as a pan-European specification and is heavily adopted throughout Europe. However, HbbTV is also gaining acceptance outside of Europe, with deployments planned or underway in countries such as South Korea, Japan, China, and the United States. In addition, numerous name-brand television and set-top-box manufacturers are producing HbbTV-enabled devices, providing both choices and healthy competition in markets where HbbTV has been rolled out.
As HbbTV adoption continues, taking MPEG-DASH with it into more real-world deployments in Europe and beyond, it further bolsters the use of DASH as the standard of choice for streaming media.
4. DASH will “play nice” with HTML 5
If you’ve read our blog post on HTML5, you know it’s not the Holy Grail for streaming media playback experiences. However, the powerful combination of MPEG-DASH and HTML5 would bring together the latest industry standards for both Web-based development and video delivery. Recognizing this, the W3C HTML Working Group developed Media Source Extensions to add the power of features such as live adaptive streaming, live pause, and instant replay to HTML 5.1.
With high demand for interoperable HTML5 video streaming, we are already seeing early HTML 5.1 feature adoption in Web browsers, operating systems, applications, and devices.
However, full functionality and interoperability across them will likely not arrive for several years. Until then, delivering content to a growing number of DASH-capable media players may set you on a path to eliminate one or more older streaming formats and eventually simplify your long-term streaming media infrastructure requirements.
DASH adoption appears to be poised to accelerate rapidly, especially with its incorporation as the adaptive streaming format in other connected TV and Web standards. You can expect many of today’s multi-format streaming workflows to be replaced by a workflow centered on MPEG-DASH, thereby providing the best qualities of adaptive streaming, increasing feature parity across screens, maintaining any-screen reach, and reducing deployment complexity.
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