The introduction of HD video has had a tremendous impact on the adoption of video conferencing. Before HD, the experience of rooms-based video conference left much to be desired: imagine a scenario where a CIF image (352x288) shows 7 or 8 people seated around a conference room table. The number of pixels capturing facial expressions of each individual in the room was extremely small, and as a result the visual channel didn’t add much value to the interaction. This left many people believing that video conferencing wasn't worth the hassle.
HD has addressed this shortcoming by significantly increasing the amount of visual information (a 1080p image provides 20 times the information of a CIF image) which communicates more of the body language and facial expressions of conference participants. With HD, video conference finally cleared the minimum quality threshold that was required to get customers to believe that video really adds value. Telepresence takes that to the next level by marrying HD video conference with intelligent room layouts, camera placement, multiple video streams, and other enhancements that improve the overall experience. All of this has led to a rapid acceleration of the adoption of video communications.
What’s interesting to note, however, is that desktop video conferencing is able to deliver many of the same benefits of Telepresence without the expensive room setups even at non-HD resolutions. Consider a typical telepresence room layout where each monitor captures the image of two people seated at a remote table. The rectangular area capturing the face and torso of each of these people is roughly the size of a VGA image. At the same time, VGA images have become the standard in the desktop video world, and are now routinely communicated using 300-400kb/s. This means that a desktop video session running at 400kb/s is able to convey roughly the same amount of facial information as a Telepresence session, but at a fraction of the bandwidth.
The biggest impact of HD, then, might be that HD video will finally get people to adopt video at large scales, but they will almost certainly do so using inexpensive desktop technology, using VGA resolutions rather than real HD. For desktop video, HD will have been the catalyst, but HD may not be what will ultimately be the standard at the desktop.