scalable video coding (SVC)

Scalable video coding (SVC) is an extension of the H.264 (MPEG-4 AVC) video compression standard for video encoding. 

The video codec allows video transmission to scale so that content is delivered without degradation between various endpoints -- for example, between a laptop and a mobile device. The SVC codec translates bits from a network data stream into a picture and conversely translates camera video into a bit stream. It breaks up video bit streams into bit stream subsets that add layers of quality and resolution to video signals. 

SVC codecs adapt to sub-par network connections by dropping these bit stream subsets or packets in order to reduce the frame rate, resolution or bandwidth consumption of a picture, which prevents the picture from breaking up. For example, a mobile phone would receive only the base layer or bit stream while a high-definition video conferencing console would receive both the base layer and bit stream subset or enhancement layer.

SVC is backwards compatible, so an SVC codec can communicate with an H.264 codec that is not SVC-capable. A number of video conferencing equipment manufacturers embrace SVC encoding, including Avaya (Radvision), LifeSize, Polycom and Vidyo.