Brent Kelly
Brent Kelly is president and principal analyst at KelCor, Inc., where he provides strategy and counsel to key client types...
Read Full Bio >>

Brent Kelly | September 02, 2013 |


Vidyo-Google Announcement of VP9 SVC for WebRTC: Why It's Important

Vidyo-Google Announcement of VP9 SVC for WebRTC: Why It's Important Vidyo is positioned to see tremendous benefit from a revenue and deployment perspective as WebRTC clients proliferate using VP9 SVC

Vidyo is positioned to see tremendous benefit from a revenue and deployment perspective as WebRTC clients proliferate using VP9 SVC

Google and Vidyo jointly announced an agreement in which "Vidyo will develop a scalable video extension for the VP9 codec as part of the WebRTC client open source project". What does this really mean, and what will be the impact for both WebRTC and Vidyo?

This article will explore the implications of the announcement, but first will offer some background on the technology.

A Short Discussion of Video Encoding
Digital video must be compressed, using a video codec, so that it can be transmitted efficiently over a network. Although many video codecs exist, the most prevalent in the enterprise video conferencing industry today are H.263 and the newer H.264. Another codec, VP8, is the video codec currently available in the WebRTC implementations available via Google Chrome and Mozilla Firefox browsers. Google is currently working on the next iteration of its VP codec, VP9.

The H.264 codecs allow video to be compressed into bit rates that are half or less of the H.263 bit rates, for equivalent video quality. H.264 "AVC" or baseline profile codecs have been available since they were approved by the ITU in May 2003, and several clarifications or enhancements have been added since then.

One of the most significant enhancements, approved in November 2007, was H.264 Scalable Video Coding (H.264 Annex G). SVC leverages the same encoding techniques but allows the encoding engine to split the video into a base layer, called AVC, and several enhancement layers or streams. These enhancement layers can represent spatial resolution (screen size), temporal resolution (frame rate) or video image quality. Vidyo was the company that really brought H.264 SVC into the video conferencing world through its line of SVC-enabled Vidyo endpoints and infrastructure.

It is this additive capability of SVC layers that makes this encoding technique so compelling, because it eliminates the need for video transcoding and bridging devices. Even if some layers of the full video stream are removed, the resulting sub-layers form a valid video bit stream for target endpoints supporting lower quality . For example, a mobile phone, with a small screen, requires a much smaller amount of video information in order to show a high quality image on its small display; consequently, it does not need or use all of the SVC layers a telepresence system would require. Contrast this to a non-SVC call in which a transcoding video bridge would be required to connect systems with different resolutions to the same call.

Figure 1. H.264 SVC Introduces Temporal, Spatial and Quality Video Layers

It is the responsibility of the SVC-compliant endpoints to signal the capabilities they have to other endpoints and to any infrastructure participating in the call. Note that SVC does not use less bandwidth than AVC; it may actually increase bandwidth by 10% to 15% compared with AVC. But the tradeoff is worth it because the video infrastructure should in principle be less expensive.

SVC-encoded video performs better over networks with significant packet loss or with less available bandwidth; this is because it sends only those video layers that can make it through the network and which are then used in the decoding process to reconstruct the video image at a lower frame rate or possibly a lower image size or even at a lower video quality. H.264 AVC and H.264 SVC both require about half the bandwidth of the older H.263 codec, and it is anticipated that H.265 and VP9 will require about half of the bandwidth of their predecessors.

Compressing video using newer video codecs usually requires more CPU processing than does compressing a codec's earlier versions. Consequently, care must be taken when deploying a new version of a codec, because one must assure that the devices on which this video is to be compressed have enough processing power.

Not all SVC encoders are created equal. The standard really defines how to decode video, not encode it. So video encoders from different vendors will support varying video quality and bandwidth efficiencies. In principle, all encoders encoding the same video standard should at least interoperate at the base layer. The reality is that implementations from different vendors may not interoperate, even for the base layer, and SVC implementations certainly do not interoperate. In addition, some incompatibilities even for the same codec (H.264, for example) may arise due to proprietary signaling a vendor may choose to use.

Figure 2 below shows the video compression codecs used by major desktop video conferencing vendors.

Figure 2. Video Compression Codecs Used in Several Desktop Video Solutions

* Note that Lync 2013 does not support H.263. Lync 2010 does support H.264. Also see for more details on the Microsoft codecs.
** The Vidyo endpoints do not support H.263 nor H.264 AVC natively. A gateway is required to connect with these endpoints. Vidyo asked that H.263 and H.264 be placed in this list so that readers would not be misled into thinking that Vidyo does not support these older codecs at all.

A Short Discussion of Multipoint Video
The first question many video users ask after experiencing a point-to-point video call is how to have a video meeting with three or more people. There are basically two mechanisms for enabling multiparty video, depending upon which codecs and bridging hardware are being used: a Multipoint Control Unit (MCU) or a video media relay server.

Traditional MCUs
If multiple endpoints in a call are using single-layer codecs like H.264 AVC or H.263 (or earlier codecs), then an MCU is required for audio and/or video bridging. (This assumes continuous presence, i.e., video from multiple video endpoints viewable simultaneously on the same screen, sometimes called "Hollywood Squares" video). Each video endpoint enters into a point-to-point call with the MCU. The MCU receives video feeds from all endpoints and mixes both the audio streams and the video streams and then sends a single audio and a single video stream back to each endpoint.

In order to do this mixing, the MCU must first decode the audio and video streams. It then combines or mixes the audio, often mixing only two or three of the audio inputs with the most amplitude. Simultaneously, the MCU takes those images corresponding to the loudest audio inputs and puts them together in a smaller single image. It then re-encodes the audio and video, and returns these streams to the individual endpoints. (There is more processing than is described here; for example, there has to be some subtraction when mixing audio so that a speaker's own audio is not returned. However, for the purposes of this paper, the description here will suffice.).

Figure 3. How A Traditional MCU Mixes Video

MCUs exist as software running on a server or as dedicated hardware with Digital Signal Processing (DSP) chips. Large enterprises typically use hardware-based MCUs for performance reasons. By the nature of the processes involved, MCUs add some latency (typically less than 200 milliseconds) to a multipoint video conference. In addition to doing the processing necessary to create a composite video image, the MCU must have "jitter" buffers to reassemble packets that arrive out of order, a common occurrence on many networks. Also, because there are multiple encode/decode cycles, the video quality will slightly degrade.

Next Page: The significance of the Vidyo-Google announcement


April 25, 2018

Yesterdays simple phone call to a contact center or business location is rapidly becoming todays interactive session, spanning multiple channels and devices. If you need to know how Omnichannel can

March 7, 2018

Video collaboration is experiencing significant change and innovation-how can your enterprise take advantage? In this webinar, leading industry analyst Ira Weinstein will present detailed analysis

February 21, 2018

Business agility has become the strongest driver for enterprises to begin migrating their communications to the cloud-and its a benefit that enterprises are already realizing. To gain this benefit

March 12, 2018
An effective E-911 implementation doesn't just happen; it takes a solid strategy. Tune in for tips from IT expert Irwin Lazar, of Nemertes Research.
March 9, 2018
IT consultant Steve Leaden lays out the whys and how-tos of getting the green light for your convergence strategy.
March 7, 2018
In advance of his speech tech tutorial at EC18, communications analyst Jon Arnold explores what voice means in a post-PBX world.
February 28, 2018
Voice engagement isn't about a simple phone call any longer, but rather a conversational experience that crosses from one channel to the next, as Daniel Hong, a VP and research director with Forrester....
February 16, 2018
What trends and technologies should you be up on for your contact center? Sheila McGee-Smith, Contact Center & Customer Experience track chair for Enterprise Connect 2018, gives us the lowdown.
February 9, 2018
Melanie Turek, VP of connected work research at Frost & Sullivan, walks us through key components -- and sticking points -- of customer-oriented digital transformation projects.
February 2, 2018
UC consultant Marty Parker has crunched lots of numbers evaluating UC options; tune in for what he's learned and tips for your own analysis.
January 26, 2018
Don't miss out on the fun! Organizer Alan Quayle shares details of his pre-Enterprise Connect hackathon, TADHack-mini '18, showcasing programmable communications.
December 20, 2017
Kevin Kieller, partner with enableUC, provides advice on how to move forward with your Skype for Business and Teams deployments.
December 20, 2017
Zeus Kerravala, principal analyst with ZK Research, shares his perspective on artificial intelligence and the future of team collaboration.
December 20, 2017
Delanda Coleman, Microsoft senior marketing manager, explains the Teams vision and shares use case examples.
November 30, 2017
With a ruling on the FCC's proposed order to dismantle the Open Internet Order expected this month, communications technology attorney Martha Buyer walks us through what's at stake.
October 23, 2017
Wondering which Office 365 collaboration tool to use when? Get quick pointers from CBT Nuggets instructor Simona Millham.
September 22, 2017
In this podcast, we explore the future of work with Robert Brown, AVP of the Cognizant Center for the Future of Work, who helps us answer the question, "What do we do when machines do everything?"
September 8, 2017
Greg Collins, a technology analyst and strategist with Exact Ventures, delivers a status report on 5G implementation plans and tells enterprises why they shouldn't wait to move ahead on potential use ....
August 25, 2017
Find out what business considerations are driving the SIP trunking market today, and learn a bit about how satisfied enterprises are with their providers. We talk with John Malone, president of The Ea....
August 16, 2017
World Vision U.S. is finding lots of goodness in RingCentral's cloud communications service, but as Randy Boyd, infrastructure architect at the global humanitarian nonprofit, tells us, he and his team....
August 11, 2017
Alicia Gee, director of unified communications at Sutter Physician Services, oversees the technical team supporting a 1,000-agent contact center running on Genesys PureConnect. She catches us up on th....
August 4, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, has lately been working on integrating enterprise communications into Internet of Things ecosystems. He shares examples and off....
July 27, 2017
Industry watcher Elka Popova, a Frost & Sullivan program director, shares her perspective on this acquisition, discussing Mitel's market positioning, why the move makes sense, and more.
July 14, 2017
Lantre Barr, founder and CEO of Blacc Spot Media, urges any enterprise that's been on the fence about integrating real-time communications into business workflows to jump off and get started. Tune and....
June 28, 2017
Communications expert Tsahi Levent-Levi, author of the popular blog, keeps a running tally and comprehensive overview of communications platform-as-a-service offerings in his "Choosing a W....
June 9, 2017
If you think telecom expense management applies to nothing more than business phone lines, think again. Hyoun Park, founder and principal investigator with technology advisory Amalgam Insights, tells ....
June 2, 2017
Enterprises strategizing on mobility today, including for internal collaboration, don't have the luxury of learning as they go. Tony Rizzo, enterprise mobility specialist with Blue Hill Research, expl....
May 24, 2017
Mark Winther, head of IDC's global telecom consulting practice, gives us his take on how CPaaS providers evolve beyond the basic building blocks and address maturing enterprise needs.
May 18, 2017
Diane Myers, senior research director at IHS Markit, walks us through her 2017 UC-as-a-service report... and shares what might be to come in 2018.
April 28, 2017
Change isn't easy, but it is necessary. Tune in for advice and perspective from Zeus Kerravala, co-author of a "Digital Transformation for Dummies" special edition.
April 20, 2017
Robin Gareiss, president of Nemertes Research, shares insight gleaned from the firm's 12th annual UCC Total Cost of Operations study.
March 23, 2017
Tim Banting, of Current Analysis, gives us a peek into what the next three years will bring in advance of his Enterprise Connect session exploring the question: Will there be a new model for enterpris....
March 15, 2017
Andrew Prokop, communications evangelist with Arrow Systems Integration, discusses the evolving role of the all-important session border controller.
March 9, 2017
Organizer Alan Quayle gives us the lowdown on programmable communications and all you need to know about participating in this pre-Enterprise Connect hackathon.
March 3, 2017
From protecting against new vulnerabilities to keeping security assessments up to date, security consultant Mark Collier shares tips on how best to protect your UC systems.
February 24, 2017
UC analyst Blair Pleasant sorts through the myriad cloud architectural models underlying UCaaS and CCaaS offerings, and explains why knowing the differences matter.
February 17, 2017
From the most basics of basics to the hidden gotchas, UC consultant Melissa Swartz helps demystify the complex world of SIP trunking.
February 7, 2017
UC&C consultant Kevin Kieller, a partner at enableUC, shares pointers for making the right architectural choices for your Skype for Business deployment.
February 1, 2017
Elka Popova, a Frost & Sullivan program director, shares a status report on the UCaaS market today and offers her perspective on what large enterprises need before committing to UC in the cloud.
January 26, 2017
Andrew Davis, co-founder of Wainhouse Research and chair of the Video track at Enterprise Connect 2017, sorts through the myriad cloud video service options and shares how to tell if your choice is en....
January 23, 2017
Sheila McGee-Smith, Contact Center/Customer Experience track chair for Enterprise Connect 2017, tells us what we need to know about the role cloud software is playing in contact centers today.