Error resiliency schemes in H.264/AVC standard

Sunil Kumar, Liyang Xu, Mrinal K. Mandal, Sethuraman Panchanathan
2006 Journal of Visual Communication and Image Representation  
Real-time transmission of video data in network environments, such as wireless and Internet, is a challenging task, as it requires high compression efficiency and network friendly design. H.264/AVC is the newest international video coding standard, jointly developed by groups from ISO/IEC and ITU-T, which aims at achieving improved compression performance and a network-friendly video representation for different types of applications, such as conversational, storage, and streaming. In this
more » ... , we discuss various error resiliency schemes employed by H.264/AVC. The related topics such as nonnormative error concealment and network environment are also described. Some experimental results are discussed to show the performance of error resiliency schemes. Index Terms: H.264/AVC, JVT, MPEG-4 Part 10, video coding standards, video coding, video compression, error resiliency, error-resilient video coding. applications that are likely to use transmission media such as Cable Modem, xDSL, or UMTS that offer much lower data rates than broadcast channels [2] . Apart from better coding efficiency, the standard has also given strong emphasis to error resiliency and the adaptability to various networks [2] . To give consideration to both coding efficiency and network friendliness, H.264/AVC has adopted a two-layer structure design (Fig. 1) : a video coding layer (VCL), which is designed to obtain highly compressed video data, and a network abstraction layer (NAL), which formats the VCL data and adds corresponding header information for adaptation to various transportation protocols or storage media [2] . For stream-based protocols such as H.320, H.324M or MPEG-2, the NAL delivers compressed video data with start codes such that these transport layers and the decoder can robustly and easily identify the structure of bit stream. For packet-based protocols such as RTP/IP and TCP/IP, the NAL delivers the compressed video data in packets without these start codes [3] . A coded video sequence in H.264/AVC consists of a sequence of 'coded pictures'. A coded picture can represent an entire frame or a single field (for interlaced frame). However, we shall use the term 'frame' to represent both the entire frame as well as a field, in this paper. The main features of H.264/AVC, which distinguish it from the previous video compression standards, are briefly discussed below [2, 3]: • Two context adaptive coding schemes, CAVLC (context-adaptive variable-length coding) and CABAC (context-adaptive binary arithmetic coding), improve coding efficiency by adjusting the code tables according to the surrounding information.
doi:10.1016/j.jvcir.2005.04.006 fatcat:y5shnfdwzncknd7polvcvu3hz4