It’s no secret that streaming media has more momentum now than at any previous point in our industry’s history. Where we once talked about the future of streaming, we are living it today. You cannot pick up a phone or tablet or turn on the TV without being exposed to a variety of streaming media offerings. From Amazon Prime Video to Netflix, from Pandora to Amazon Prime Radio, streaming has quickly become the de-facto model of distributing premium content to online viewers.
As a pioneer in the streaming media industry I have seen literally hundreds of different technologies come and go—and in some cases, come back. That’s not to say that the road to today has been paved with more successes than failures but clearly we have cycled through quite a few workflows and deployment platforms over the years as a collective industry.
For about 7 years now our industry has been a two-format camp—Flash
versus Silverlight—for video streaming. Before that it was RealPlayer versus Windows Media Player and its predecessor NetShow. Before Steve Jobs left this mortal coil, he misguidedly convinced the world to put a stake into the heart of the most popular video playback platform, Flash.
This premature death caused a “man the lifeboats” response, which quickly pointed to plugins like Flash and Silverlight and QuickTime and RealPlayer as the bane of our streaming media experience. Quite honestly, I will never understand how and why this happened, but it did. Our collective reflexive response was to “explore strange new worlds, to seek out new life and new civilizations, to boldly go where no (wo)man has gone before.”
Out of this experiment came the notions of HTML5 and DASH. The idea was that, using a readily available client like a browser, consumers could watch all the streaming video they wanted via a ubiquitous format like DASH. By eliminating the unique benefits of plugins and replacing them with more standardized playback elements in a browser, the concept of a universal playback platform and format was born.
It has been written “Those who have the youth, have the future.” Many of you reading have served in this industry a long time. You have seen trends come and go and technologies rapidly adopted or alternatively, discarded. For you, the future is today. I propose to you that DASH is the format of the future, today.
Let’s take a closer look at the major pain points that DASH addresses.
For More Information about DASH, CENC and HbbTV Visit:
DASH IF: http://www.dashif.org
Since its inception, the core MPEGDASH open standard has been a permissive one, allowing a virtually unlimited combination of video codecs and containers, audio codecs, and even transport vectors. While this flexibility has generated traction in the industry, as DASH can be leveraged to cover various use cases, too much flexibility raises the risk of incompatible deployments. Once DASH was published in April 2012 as the ISO/IEC 23009-1 standard, the challenge was to carefully select a smaller set of core features from the base specification and to enrich this base with a combination of complementary technologies and proven use cases, in order to ensure DASH is the best choice for interoperable deployments of adaptive streaming bitrate technology.
A BIT OF HISTORY
Interoperability is—and always has been—a primary mission of the DASH Industry Forum. The DASH Industry Forum (also known as DASH-IF) was officially incorporated in September 2012 as the successor to the previous DASH Promoters Group. After the DASH-IF was founded by Microsoft, Qualcomm, Netflix, Samsung, Ericsson, and Akamai, it quickly gained support
from other major industry actors such as Adobe, Cisco, Dolby, DTS, and Harmonic—along with many dynamic companies from various sectors of the video ecosystem. As of September 2014, the DASH Industry Forum counts 76 member companies (see the full list at http://dashif.org/members/) that are committed to work together on concrete DASH interoperability points and DASH promotion. The recent addition of Google as a member brings a decisive acceleration in this convergence movement and strengthens the idea that DASH is deeply rooted in the ecosystem as the successor to proprietary adaptive streaming technologies like HLS, HDS, and Smooth Streaming.
MATCHING THE MULTI-FACETED DASH TRACTION
If DASH-IF’s initial intent was to design interoperability points with a universal reach within the industry, history has shown that that was not fully possible, as DASH has been adopted by different ecosystem segments, from Over-the-Top (OTT) streaming to desktop and mobile devices to Broadcast to Mobile—all with slightly different requirements, design
approaches, and engineering traditions. However, DASH-IF believes its interoperability points are well suited for the common OTT desktop & mobile use cases, and now works on facilitating convergence between the mentioned sectors. The benefit of convergence in terms of reducing the cost of deployment for everybody in the chain is substantial, and thus the DASH-IF fills a crucial role in the industry as the coordination and interoperability hub between various standardization bodies integrating DASH into their specifications.
Among those bodies, ISO/MPEG is the natural partner, as DASH was born there and continues to evolve: In May 2014, ISO/MPEG has published the second edition of the DASH core specification, which extends the first edition to include features such as media timeline events, blackout signaling, content asset identifiers and improved ad-insertion support. All the latest DASH-IF Interoperability Points (IOPs) and recommendations that are listed below are based on this second edition of DASH (ISO/ IEC 23009-1:2014). DASH-IF members also participate in ISO/MPEG standardization process, and DASHIF and MPEG organizations regularly exchange information in order to harmonize their efforts.
DASH-IF has also established close relationships with DVB and HbbTV organizations, facilitated by a great collaboration with the EBU on many topics. In July 2014, DVB ratified its MPEG-DASH Profile for Transport of ISO BMFF Based DVB Services over IP Based Networks, aligning closely with DASH-IF’s implementation guidelines and adding a selection of appropriate video and audio codecs from the DVB toolbox, plus MPEG Common Encryption and EBU-TT-D subtitles. The HbbTV consortium has chosen to integrate the DVB-DASH Profile in its next HbbTV v2 specifications, which are expected to be published in early 2015. On top of the already mentioned bodies, DASH-IF is in regular liaison with organizations like SCTE, SMPTE, DECE, 3GPP, ATSC, W3C, and DLNA, as they are leading relevant standards used inside DASH-IF IOPs or integrating DASH inside their own specification scope, like 3GPP with eMBMS or DLNA with its CVP-2 Guidelines. ATSC is currently considering DASH for its version 3 specifications, while DECE is working on the UltraViolet Common Streaming Format, which is based on Common File Format and aligned with MPEG-DASH and DASH-IF Implementation Guidelines to provide adaptive streaming over HTTP in the UltraViolet context.
In June 2013, DASH-IF published the final version of its DASH-AVC/264 Implementation Guidelines. The objective was to marry a subset of the base DASH profiles included by ISO/ MPEG (ISO BMFF Live and On-Demand profiles) with H.264/AVC video codec, HE-AACv2 audio codec, Common Encryption (ISO 23001-7), multiple DRM signaling, HTTP/1.1 and subtitling with SMPTE-TT. In order to lower implementation complexity, some constraints were applied to the original ISO BMFF profiles: MPD playlist-based addressing, multiplexed media as well as open GoP switching were excluded from the scope. Based on this assembly of technology that DASH-IF believed sufficient to cover most of the needs, two interoperability points were defined:
DASH-AVC/264 SD: supporting H.264/AVC Main Profile up to Standard Definition
In August 2013, the version 2 of the DASH-AVC/264 Implementation Guidelines was released, bringing two major enhancements over version 1: the support for 1080p video distribution and multichannel audio technologies. The document also introduced specific considerations for Live Services, client/ server time synchronization as well as audio loudness and dynamic range support applied to HE-AACv2. This release generated two more items:
Based on this foundation, DASH-IF’s Interoperability Working Group then expanded its efforts to cover the latest technology evolutions, and provided the version 3 of the Guidelines for community review in August 2014. Due to the integration of H.265/HEVC codec, the specifications are now referenced as “DASH-IF Interoperability Points.” The other main evolutions are additional support for CEA608/708 closed captioning and the alignment with the 2nd edition of the MPEGDASH core specification (which covers backward compatibility to DASH v1.0). Some enhancements to DRM signaling and trick modes support were also added. The result is three new Interoperability Points:
The document is currently available for community review until November 1st at http://dashif.org/white-papers/ and the final version of the Guidelines are expected to be published before end of 2014. DASH-IF encourages companies and industry experts to submit their feedback through the available online tool.
On top of producing the core interoperability guidelines, DASH-IF has established specialized task forces that are working on complementary topics: Advertising Insertion, Live Streaming, and DRM Backend Interfaces. The latter task force is due to finalize a recommendation later this year, focused on providing a reference model for exchanging keys and DRM metadata between encoder/ packagers and DRM systems. In the meantime, two recommendation documents have been issued for community review with the same schedule as the Interoperability Points Guidelines:
The scope of the Live Services Guidelines is to provide content authoring and client implementation requirements, recommendations, and guidelines for distributing live and linear TV services with MPEGDASH. The document covers ten different use cases (from scheduled live service to 24/7 live service) and several architecture types (unicast delivery through a CDN and multicast delivery through eMBMS). It defines two interoperability points for live services:
• DASH-IF Live Service Legacy
(mapped to ISO/IEC 23009-1 v1
and DASH-IF IOPs up to v2)
• DASH-IF Live Service Main
(mapped to ISO/IEC 23009-1 v2 and DASH-IF IOPs up to v3)
The Main IOP brings the ability to trigger manifest updates through in-band messages in segments, URL generation patterns based on manifests and segment information, and finally the signaling of timeline gaps at representation level.
The Ad Insertion Guidelines specify the reference architecture and interoperability points for a DASH-based ad insertion solution. The baseline reference architecture addresses both server-based (typically used with Apple HLS) and app-based (typically used with Microsoft Smooth Streaming and Adobe HDS) scenarios. The tools that are used to handle ad insertion are XLink (dynamic referencing of external elements to a manifest), DASH events (messages embedded directly in a MPD or transported in media segments), and MPD Updates (refreshing the manifest at specific intervals). The Guidelines indicate how a DASH packager is expected to translate MPEG-2 transport SCTE 35 cue messages in both scenarios. The following Interoperability points are defined in the document:
DASH-IF believes these Guidelines cover the majority of the Ad Insertion scenarios and thereby facilitate a safer migration from older adaptive streaming architectures to DASH.
In order to ease the implementation of its recommendations as well as advance the DASH standard in general, DASH-IF has been working on several initiatives designed to help developers validate the compliance of their DASH-enabled solutions. Interoperability Points are translated into a set of test cases in the “Guidelines for Implementation: DASH-AVC/264 Test Cases and Vectors” document to be finalized by November. It’s a valuable resource for companies developing encoding/packaging solutions. Player developers might be more interested by the Test Vectors repository (http://dashif.org/testvectors/).
WHAT’S NEXT ?
DASH-IF believes that once the DASH-IF Interoperability Points Guidelines version 3 are finalized, they will lay the ground for swift and stable deployments of HEVC-based OTT video services. For the version 4 of its Guidelines, DASH-IF wishes to add new Interoperability Points dedicated to Ultra HD profiles. As the UHDTV standardization movement is in the works and several organizations like EBU, DVB, and SMPTE are collaborating to finalize all aspects of UHDTV Phase 1 (2160p50/60) specifications, DASHIF is eager to collect feedback from other organizations on the UHDTV topic, in order to generate relevant implementation guidelines. Additional topics expected to be addressed are optimized low-latency live services; inclusion of new transport mechanisms such as broadcast/multicast and HTTP/2.0, authentication frameworks; and support of operational end-to-end workflow optimizations by defining metrics and reporting.
PROMOTION, EDUCATION, AND ECOSYSTEM ANIMATION
Alongside numerous technical activities discussed above, DASH-IF— through its Promotion Working Group—is also at the forefront of the promotion of the DASH standard, and works throughout the year to organize educational events like the IBC 2014 DASH Supersession or the DASH Talks NAB 14 (replay available on http://dashif.org/dash-talks-nab-14/) to share DASH latest updates. In 2014 the first DASH Roadshow was organized in Japan and will be replicated in other regions to bring DASH evangelists even closer to the local video ecosystems. Many DASHIF members speak during webcasts and tradeshows worldwide all year long, and are appreciated as they share valuable knowledge and insights. DASH-IF also organized networking events like the IBC 2014 Networking Reception which recently gathered 280 DASH enthusiasts at the Heineken Brewery in Amsterdam.
DASH-IF NEEDS YOU!
Finally, consider the guidelines that DASH-IF is producing and promoting, as they believe that the industry will be stronger if we adopt a common interoperable version of DASH wherever possible.
ABOUT DASH INDUSTRY FORUM
Formed in 2012, DASH-IF is the organization responsible for promoting market adoption of the MPEG-DASH standard for interoperable streaming of multimedia content over Internet.
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