Very low bit rate video coding using vector-based techniques

This paper reports the advances of using vector-based techniques for very low bit rate video coding. High efficiency has been achieved for coding intraframes (the first frame and subsequent refreshing key frames) and motion compensated difference frames of a video sequence. A video frame (I or P frame) is first decomposed into a set of vector bands using a vector wavelet transform. Adaptive lattice vector quantization is then used in the vector bands. A 100% labeling efficiency is achieved for lattice vector quantization by using a set of generalized labeling algorithms for various important lattices with pyramid and sphere boundaries. An adaptive algorithm is used to determine the type of lattice vector quantisation according to the statistical distribution of the vectors in the vector wavelet domain. Finally, entropy coding is used to code the indexes generated from lattice vector quantization. Our coding results show that a gain of 3 to 8 dBs in PSNR for intraframe coding can be achieved at a bitrate level of 16 Kbpf over H.263. Subjective quality improvement of the proposed algorithm over H.263 can be observed.