Scalable Video Coding in H.264/AVC

The Scalable Video Coding amendment (SVC) of the H.264/MPEG-4 AVC standard [add link to page "H.264/AVC overview"] provides network-friendly scalability at a bit stream level with a moderate increase in decoder complexity relative to single-layer H.264/MPEG-4 AVC. It supports functionalities such as bit rate, format, and power adaptation, graceful degradation in lossy transmission environments (cp. Figure 1) as well as lossless rewriting of quality-scalable SVC bit streams to single-layer H.264/AVC bit streams.

Video coding today is used in a wide range of applications ranging from multimedia messaging, video telephony and video conferencing over mobile TV, wireless and Internet video streaming, to standard- and high-definition TV broadcasting.  Furthermore, video content is delivered to a variety of decoding devices with heterogeneous display and computational capabilities (see Figure 2). In these heterogeneous environments, flexible adaptation of once-encoded content is desirable, at the same time enabling interoperability of encoder and decoder products from different manufacturers.

Contributions of the Image and Video Coding Group

The image and video coding group contributed the following techniques to the SVC design and encoding concepts:

  • The first SVC Model that became the first Working Draft
  • Hierarchical prediction structures for providing temporal scalability, generally improving the coding efficiency, and improving the effectiveness for inter-layer prediction tools in spatial and quality scalable coding
  • Inter-layer prediction tools for spatial and quality scalable coding
  • The concept of decoding enhancement layers with a single motion compensation loop as part of the inter-layer prediction design
  • The key picture concept for efficiently controlling the drift in packet-based quality scalable coding
  • The concept of transform coefficient partitioning for increasing the granularity of packet-based quality scalable coding
  • An rd-optimized multi-layer encoder control for improving the coding efficiency of SVC encoders