DASH it all?

MPEG-DASH has been ratified by 24 national bodies, a topic covered in a recent StreamingMedia.com article and also at StreamingLearningCenter.com (run by Jan Ozer).

Now that we, as an industry, have reached a tentative agreement on how to handle adaptive streaming over HTTP through consistent parsing of manifest files (MPD or Media Presentation Description in MPEG DASH parlance) there's another question remaining: what's next?

The next two steps, as noted in both the Streaming Media article and our own white paper, is the acceptance of a common file format and a common encryption scheme (CENC).

Following ratification of CENC and adoption of the common file format, there's a huge need to deal with interoperable, DASH-compliant players. In fact, this element may be the biggest challenge of all—getting encoded content to consistently play back on every device or platform.

It's the same issue we faced during the two reports (1, 2) on Android handset and tablet video playback, where core services of Android didn't necessarily translate into consistent playback of RTSP or even YouTube videos on a variety of playback devices from the same handset manufacturer.

So Transitions is issuing a challenge, as part of our 2012 Q1 Best Workflows testing: bring us your DASH-compliant player, whether it's in beta or gold master, and we'll put it through its paces against other DASH-compliant players, using consistent fMP4 and M2TS content. Here's looking at you, Qualcomm, Ericsson and even Microsoft and Adobe...

Why are fMP4 and MPEG-DASH so important?

Quote from a white paper Transitions just completed on fragmented MP4 (fMP4) and MPEG-DASH:

Proponents say that the Common File Format (CFF) and Common Encryption (CENC) scheme will represent two important steps toward large-scale online video distribution via adaptive delivery of fragmented elementary streams.


Since CFF can also be used outside of the bounds of UltraViolet, significant interoperability may also exist between UltraViolet disc-based playback and online video platforms, in much the same way that the DVD Forum’s published specifications for DVD playback guaranteed interoperability between DVD players. It’s not out of bounds to think of CFF as the DVD standard for the web.


To get a better understanding of the power of fragmented MP4, first look at the sidebar in the white paper on "combinatorial complexity" for which Netflix contributed a real-world example. Even without CFF and CENC, Netflix is proving the case that fMP4 scales much better than the HLS approach (with a far lower asset management impact).

The white paper has been several months in the making, starting first as separate concepts by two key companies in the streaming space: Adobe Systems and Microsoft Corporation. Each has their proprietary solutions, but both are committed to seeing fragmented MP4 (fMP4) offer a potentially viable alternative to legacy streaming solutions.

After several meetings, both companies chose to jointly work with Transitions to create a white paper noting the benefits of fMP4 and, to a slightly lesser extent, the potential benefits of MPEG-DASH (a proposed standardization of dynamic streaming over HTTP that I mentioned in a prior blog post).

Special thanks to Microsoft and Adobe for providing financial resources and access to subject-matter experts, who spent time expanding on key concepts and the ever-changing nature of fragmented MP4 and the MPEG-DASH ratification process.

The full white paper can be found here.

[Addition: Adobe and Microsoft have both published blog posts, outlining their support for fMP4 and mentioning reasons for working together: Adobe's Kevin Towes blog post  Microsoft's Chris Knowlton blog post]

DASH of this, DASH of that...

It's apparent that MPEG-DASH is getting traction—or at least attention—if attendance at the 2011 StreamingMedia West show's panel on MPEG-DASH is any indicator.

It wasn't just standing-room, as alluded to in the StreamingMedia.com article, but was sitting-room only. It's been quite some time since I've seen this level of interest in a topic.

A few notes that didn't make it into the article:


MPEG-DASH will never define a codec, but with DASH-264 there's a move to use an H.264 codec in an MP4 container with a common file format (CFF) and common encryption (CENC).... There's also a possibility of adding DASH-264 into the HTML5 standard, since W3C requires a codec to be considered in HTML5 but MPEG-DASH itself is codec agnostic.


Interesting note about who has been participating and who has not:


Apple has been participating in MPEG-DASH from the beginning; they have contributed actively. We've not seen Google participating in DASH, but our codec agnostic approach means that WebM could be used within DASH (we can already do with profiles around M2TS).


What about royalties? An audience member's question got this reply:

From a licensing standpoint, there is a requirement to notify ISO of their intent to license; Qualcomm and Cisco have announced they'll offer royalty-free since HTTP adaptive streaming has been done for a number of years but to get to a standard we need to see a path forward to royalty-free licensing.