Rate Control in Video Coding

Rate control plays an important role in video coding, although it’s not a normative tool for any video coding standard. In video communications, rate control must ensure the coded bitstream can be transmitted successfully and make full use of the limited bandwidth. As a consequence, a proper rate control scheme is usually recommended by a standard during the development, e.g. TM5 for MPEG-2, TMN8 and TMN12 for H.263, and VM8 for MPEG4, etc. H.264/AVC is the newest international video coding standard, and some work on rate control has been done for H.264/AVC too. In the contribution, a rate control scheme based on VM8 is adopted by H.264/AVC test model. In another contribution, an improved rate control scheme for H.264/AVC is provided with rate distortion optimization (RDO) and hypothetical reference decoder (HRD) jointly considered, part of which has also been adopted by H.264/AVC test model.