Latency Matters

Sometimes people use the expression “timing is everything” very loosely, but when it comes to real time video communication, this colloquialism rings true. It is both irritating and frustrating when you are trying to have a meaningful exchange with someone and you end up with pregnant pauses between the time that you say something and the other end receives it. The results: frequent air-time collisions and lip sync so bad you feel like you’re conversing with a ventriloquist. This delay between transmit and receive is known as latency.

Latency has long been one of the most significant factors inhibiting video conferencing adoption. Those who struggled through it, did so for years because there were no alternatives. There are several contributing factors to the “glass to glass” latency in a video conferencing system, including network traversal, endpoint encode and decode, and, the greatest source of latency, the transcoding MCU. Now, however, with the arrival of a new class of solutions that have eliminated the need for transcoding, including Vidyo’s personal telepresence, end users have options and are beginning to demand more natural interactions from their visual communications experiences.

At the Visual Communications Industry Group’s first annual conference in Ft. Lauderdale, FL this week, Bob Dixon of the Ohio Academic Resources Network and Ben Fineman of Internet 2 hosted a session on Desktop Collaboration Tools. Vidyo and three other vendors were invited to participate in the session to provide a live demonstration of their desktop solution, have a couple customers join via their tool to talk about their use cases, and give a brief presentation regarding the solution.

Tandberg withdrew from the event citing that they wouldn’t have anyone in the area to do it… When Polycom gave their demonstration and presentation. Latency. Like Tandberg their dependency on the transcoding MCU for multipoint conferences puts them at a disadvantage in terms of performance.

Users in the audience, after suffering through the latency issue for years, were quick to identify it and were effectively demanding a higher quality solution. In short, they were looking for Vidyo. Happily, they found us on the show floor and in our presentation on scaling video conferencing deployments. And soon, they’ll find us in their network, where their MCU used to be.

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Related Links:

- Visual Communications Industry Group’s Website
- Vidyo’s YouTube Channel
- The International Business Time’s Article: Cisco Home Telepresence Rumors Fuel Speculation, Doubt

4 thoughts on “Latency Matters

  1. This has been my experience too. I have tested just about every video conferencing system out there and; based on my prefered selection criteria, Vidyo, Scopia, Nefsis and VSee come out ahead of the pack.

    The criteria I use for ranking system quality is in order below:

    1.) best lip-sync (usual tactic is to turn a/v skew into delay by delaying video and allowing audio to buffer at endpoint to simulate delay of video. AV needs to be synchronized by NTP timestamps – although try to minimize this overall delay)

    2.) smoothest motion (without significantly delaying interaction) – at least 29.970, but ideally 59.940 Progressive-Frames/Sec. as an option

    3.) best edge-sharpness and spatial detail for any given resolution (without significantly delaying interaction) at least 480×360 for close camera to face distance

    4.) fewest visual artifacts (without significantly delaying interaction)

    5.) best speech intelligibility (without significantly delaying interaction) 50Hz-18KHz or similar wide-band voice-codec preferred

    6.) fewest audio artifacts (without significantly delaying interaction) 50Hz-18KHz or similar wide-band voice-codec preferred

    7.) best voice transparency (without significantly delaying interaction) 50Hz-18KHz or similar wide-band voice-codec preferred

    8.) least amount of required in/out bit rate

    9.) best end(s)-to-end(s) traversal over commodity internet

    10.) least amount of endpoint resources but sufficient to buffer a/v and post-process

    I have always tested on various networks (commodity internet / office WAN-LAN) and various PCs to simulate real world usage.

    I am anxious to again test Vidyo along with Scopia Desktop, Spirit DSP’s VideoMost, Nefis and VSee in the latest versions in my on-going mission to use the best video conferencing platform. I have high expectations of Vidyo’s quality based on my earliest exposure to it when I was given access to my own server app and client when Vidyo was still going by Layered Media.

    Exciting times!

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