Vidyo Interview – Dr. Alex Eleftheriadis

When I started blogging, I just wanted to help people understand video conferencing and other cool technology.  Along the way, I have had the opportunity to meet some great people and see some great technology.

A few days ago, I (little old me, unknown blogger) was asked if I wanted to interview Dr. Alex Eleftheriadis (Vidyo Co-Founder and Chief Scientist) before he embarks on a very interesting project, that of Chief Editor of the  UCIF (Unified Communication Interoperability Forum) Task Group on Scalable Video Coding.

I said yes!  But I asked if I could email the questions since, well, I’m more comfortable writing than talking on the phone.  They said yes!  What you see below is the “interview”.



You know I can get excited about cool technology.  BUT…it takes a whopping good product in the videoconferencing arena (’cause I’ve been there, done that) to get me really enthused.  When I first saw Vidyo (it was a different company name at that time, with a brand new concept), my friend, Ami (he is the handsome guy in the video above doing what he has done for me a hundred times…making the difficult easy), took a long time explaining to me what I was seeing (video delivered using H.264 SVC).

Being slightly on the slow side (and a hands-on learner), it took me a awhile to actually get it.  And even then…it did not really sink in until I met with several Vidyo folks via….well, errrr….Vidyo.

Here is the video call I recorded of our conversation, I think you can tell the point where I finally “get it”:

Here is the link to my complete review.

OK….enuf of the preliminaries.  🙂

The Interview

NOTE (from Vidyo PR):   Dr. Alex Eleftheriadis drives the technical vision and direction for Vidyo and also represents the company on standardization committees and technical advisory boards. He has served as the Editor of the MPEG-4 Systems specification, co-editor of the H.264 SVC Conformance specification, is co-editor of IETF’s RTP Payload Format for SVC, and has more than 100 publications and holds 16 patents in the US with 19 more pending.  Dr. Eleftheriadis is a renowned visionary in video compression and communication technology, with several awards and inventions that are used in Blu-ray DVDs and digital television systems, and an award-winning researcher. To avoid confusion, the reference to his inventions that are used in Blu-ray and digital television do not relate to his work at Vidyo, but to his work at Columbia University where he was a professor for several years. These inventions do not relate to SVC.

1.     Congratulations on your selection to be the “Chief Editor” of the UCIF Task Group on Scalable Video Coding. Very briefly could you give my readers a quick overview of the task group and what you hope to achieve?  Is there a time frame when you expect to achieve certain goals?  Do you want a blogger on your team?  🙂

Thank you. UCIF as a forum was created to facilitate interoperability between unified communication systems. It will create specifications about how the different components of a UC system are supposed to work. In fact, it intends to run a certification program though which vendors will be able to say that their systems or system components are UCIF-compliant. Obviously, the video component of a UC system today has to be based on H.264 SVC.  The UCIF Task Group on SVC has the goal of defining how H.264 SVC encoders and decoders are to be used within a UCIF-compliant system. There is great interest from the industry on this, so we expect to produce a specification in 6-12 months.

2. Can you give us an idea of the value of H.264 SVC versus ordinary, boring (just kidding), H.264 (MPEG4) ?

I think the best way to describe it is to use an analogy. H.264 SVC is the 4-wheel drive version of H.264. It is an extension of the original H.264 spec that is much better suited for running on best-effort networks such as the Internet, for adapting to users that may join a session with different network speeds, or different computer capabilities, etc. As far as interactive communications is concerned, it’s an “off-road” world out there and SVC is what you want to be driving.

It’s important to know that H.264 SVC is still H.264. In fact the SVC part is an appendix of the H.264 specification. It’s also important to know, to avoid confusion, that MPEG-4 AVC and H264 (with or without SVC) is one and the same thing – it’s the same specification which happens to have two “parents”, two standardization bodies that worked together to produce the specification (ITU and ISO).

3. Are there other technologies where H.264 SVC would be, or is being, used (other than videoconferencing)?  Streaming video to the home?  Blu-ray?   Surveillance?  Television?  Other?

That’s a very good question. When delay is not an issue, such as when you are streaming a movie to your computer or TV, vanilla H.264 is just fine.  This is because you can give yourself a lot of extra time before you start playing (a few seconds is typically enough) as a “buffer” – if something happens on the network, you keep playing from the buffer until the problem is resolved. If the buffer is big enough, the user doesn’t even know there was a problem. You cannot do that for communication applications such as videoconferencing because you want low delay – I want to hear you as soon as possible after you speak.

So for applications such as streaming video, Blu-ray, or traditional television (over-the-air, cable, or satellite), you don’t really need SVC. I am not aware of any commercial use of SVC in these areas. I can certainly see how SVC would be useful in surveillance, but I only have anecdotal evidence of its use.

4. If company A has an H.264 SVC solution, and Company B has an H.264 SVC solution…will they automatically inter-operate?  Or are there subtle differences that might prevent interoperability?  Will a Blu-Ray disc encoded in H.264 SVC (if this is possible) work on my existing “old” Blu-Ray player at home?

No, they will not automatically interoperate. You see, the video coding technique is only part of the story. The solution has to use several other components for the whole thing to work. Vidyo has built a completely new architecture for doing multi-party videoconferencing that is based on SVC, but has several other components as well. The core of our architecture is the VidyoRouter, a small server that completely eliminates the old MCU.  This is a big architectural change, and one that allows us to have tremendous error resilience and extremely low delay.  We use standards wherever we can, but – because what we do is new – there are parts that are not covered by any standard yet. We are very actively working on standards bodies to rectify this, and I personally spend a very large portion of my time in these activities. I was co-editor of the H.264 conformance specification, and of the IETF RTP payload format for SVC, the standard that defines how SVC is transported on the Internet. The reason why we have done all this is because we believe that interoperability is extremely important. Note that, so far, we have been the only company shipping an SVC-based product, so there was nobody to interoperate with.  Now that the whole industry appears to be changing direction and moving towards SVC, I believe our standardization efforts will bare fruit. Much more remains to be done, but we are in the right direction.

For legacy H.264 devices and systems, we offer our gateway product, which allows endpoints and MCUs to join SVC sessions. Regarding Blu-ray, it does not use the SVC part of H.264 and I am not aware of any plans to do so.

5. Finally…do you see H.264 SVC technology (is it software, hardware, or a mix?) moving to the mobile market (Android, IPhone, IPad) or will it be mostly in corporate infrastructure products and /or large consumer products such as TV’s, Blu-Ray players, etc.?

What? You have not yet seen our VidyoMobile demonstration?! Check out Our software already runs on iPhones, iPads, and pretty much everything else that we had time to compile it on.  Mind you these are not products yet, but rather technology demonstrations.

We made a very conscious choice not to use custom hardware in our system – we use standard computing technology. This means that we are as fast as Intel’s chips. That’s not a bad place to be, considering that they are investing billions to make their chips faster every year. This also means that our system can very quickly be adjusted to run on any platform that has a half-decent performance.

Thanks again, and congratulations!  A very non-Corporate:  WhooHooo!  🙂

Thank you!!


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