Progress Toward Video as the "New Voice"
The UCI Forum approves an H.264 SVC specification aimed at easing interoperability in video communications regardless of the device or connection capabilities.
High definition (HD) video streamed over the Internet is now ubiquitous in our daily lives: we can access the latest movies and TV shows from a plethora of sources and view them on display devices ranging from large-screen TVs to smartphones. However, video entertainment is unidirectional, therefore simpler to implement. Video communication presents a much more complex challenge because:
* It is bi-directional (or often multi-directional, i.e. a video conference), and all sides of the conversation need to be reasonably synchronized.
* Parties in the conversation may be using technology from multiple vendors.
* Video conferences are conducted on devices with increasingly diverse capabilities, ranging from smartphones to desktop video to rooms dedicated to video conferencing.
To address these challenges, HD video conferencing technology took another step forward this week with the publication by the Unified Communications Interoperability Forum (UCI Forum) of a new video communications specification. This document defines specific configurations of the H.264 Scalable Video Coding (SVC) standard--created by the ITU (International Telecommunication Union) and MPEG (the Moving Picture Experts Group)--for use in video communications systems. The goal of UCI Forum's project was to coordinate the output of the camera with the input requirements of the display device by addressing the "transport" definition of a video conversation.
Although the technology addressed in the standard is somewhat abstract to the average user, all users of video conferencing will be familiar with a range of issues that may arise, including:
* Picture blur, freezing and other so-called "video artifacts", e.g. blocks of "noise" being rendered on the screen.
* Audio artifacts, such as metallic ringing and "space noises."
* Delay, impeding a natural conversation flow.
These issues are caused by a combination of two things. The first is that the device potentially has insufficient processing power to cope with sending and receiving the two video streams, which could be an issue on hand-held devices. The second is that there is potentially insufficient network bandwidth to cope with the simultaneous upload and download needs of the video conversation. Once again, this can be a problem on mobile networks; and the more people that use mobile technology, the worse it will get.
These issues can be addressed by a Scalable Video Codec, i.e. one that adjusts the amount of data being sent to accommodate the needs of the situation by allowing flexibility in the refresh rate and the resolution. This new UCI Forum specification allows video endpoints to negotiate variations in scalability (or modes) to match their own display capabilities and available bandwidth, therefore to optimize the video user experience. Some video communications vendors may have already implemented these optimizations in a proprietary manner, but this specification is vendor-agnostic and therefore enables this technology to be interoperable between vendors' equipment.
In the press release related to this specification, Bernard Aboba, President of the UCI Forum, stated:
"The UCI Forum's approval of the SVC specification is a significant milestone because it represents the first step towards enabling the video conferencing and unified communication industries to offer fully interoperable video solutions. The H.264/SVC task group defined a specification that addresses the market needs as well as interoperability challenges among vendors."
Although the ITU and MPEG recently announced their H.265 standard to further optimize video compression, that standard is still in its infancy and general deployment is not expected for some time. Furthermore the scalability extension for H.265 has not yet been written. Certainly, this work done by UCI Forum on H.264 is extensible to H.265 when the time comes.
The members of the UCI Forum Task Group that authored this specification included most of the current innovators in SVC technology. This document extends other work done by UCI Forum's H.264 SVC Task Group related to the definition (and approval by the ITU) of new H.264 unified communications profiles.
Work is already underway to complete the SVC trilogy with another specification related to method of negotiating the bitstream and transport parameters via signaling protocols, and this is due by the end of this year. Once the "end to end" specifications are complete, the UCI Forum plans to implement a conformance test program to certify vendors' implementations.
This is an exciting time for the communications industry, and it will be interesting to watch how these standards and specifications are adopted and implemented to help video communications become pervasive in both our work and personal lives.