ABSTRACT

In various video compression standards, such as MPEG-1, MPEG-2, MPEG-4 video (Part 2), H.261, H.263, and H.264/MPEG-4 Advanced Video Coding (Part 10), a hypothetical reference decoder (HRD), or video buffer verifier (VBV), is specified for modeling the timing of the flow of compressed video data and decompressed pictures through a decoder. It serves to impose constraints on the variations in bit rate over time in a compressed bit stream. It may also serve as a timing and buffering model for a real decoder implementation or for a multiplexer. In this chapter, we will discuss basic concepts of video buffer management and specifications of HRD/VBV, especially for transcoders.