Info on the H.239 Protocol - People+Content, DuoVideo, Dual Video

PC connections to the Room Videoconferencing System - One connection method from the PC is via the H.239 protocol built into many modern room videoconferencing systems . . . and the second way is via direct video and audio inputs to the system (these second situations where H.239 is not available are discussed elsewhere).

The industry standard protocol is referred to as H.239. "A traditional videoconference has an audio channel, a video channel and an optional data channel. The video channel typically carries the camera image of the participants. H.239 defines rules and messages for establishing an additional video/graphics channel, often to transmit a PC graphics presentation or video from a document camera, while still transmitting the video of the presenter. . . For presentations in multipoint conferencing, H.239 defines token procedures to guarantee that only one endpoint in the conference sends the additional video channel which is then distributed to all conference participants. . . The signaling for H.239 is defined in a way which simplifies implementation of gateways between H.323 and H.320."

For TANDBERG systems, the H.239 direct PC inputs are often referred to as a DuoVideo or Dual Video stream:

For Polycom systems, H.239 is often referred to as the HDX People+Content software option license.  It's now included with all  current HDX 4000, HDX 6000, HDX 7000, HDX 8000 and HDX 9000 Series systems. Here are the current links for discount pricing and online ordering for People + Content Software Option for older systems - plus the commonly needed cable:

Model # Description MSRP
   
2457-28665-001 People+Content Cable. DVI male to VGA male, with 3.5mm audio m-m, 7.62m (25') $295
7200-22775-001 VSX People+Content includes Visual Concert VSX and VSX People+Content IP. Compatible with VSX 7000s, VSX 7000, VSX 6000 and VSX 5000. $2,059
7200-22785-001 VSX 7000e People+Content : includes ImageShare II, VGA encoder key, and VSX People+Content IP. $2,059
8200-50649-001 ImageShare II device for People+Content. Compatible with VSX 8000 Series, VSX 7000e and iPower 9000 and 600 Series. VSX 7000e requires VGA encoder key (5150-22660-001). Includes 25ft/7.5m cable to system and 3ft/.91m cable to PC $829

For LifeSize Systems, H.239 compliant Dual Video with bandwidth balance is included standard with all current systems  - ref LifeSize Product Matrix 2011

For Sony PCS Systems, they conform "to the H.239 standard, and thereby promotes the interoperability of videoconferencing endpoints from other manufacturers. H.239 stipulates how to control and manage one or more additional media channels, in addition to the main media channel. The PCS series uses the additional media channels via two functions: the Presentation function and the Dual Video function. The Presentation function and the Dual Video function that the PCS series provides can also be used in H.235 encrypted communication for when secure videoconferencing is required." Ref Sony 2010 H.239 Whitepaper.

With dual video stream you can view two different live video streams simultaneously— the main video and one additional source - in this application Skype video from the PC, Laptop, Mac or iPhone. This could also be be both a PC presentation and the person who gives the presentation. If one of the video systems does not support dual video stream, no second video stream will be established and Skype or the PC presentation will be shown as the main video.

03/05/2024