Finite state vector quantization with multipath tree search strategy for image/video coding

This paper presents a new vector quantization (VQ) algorithm exploiting the features of tree-search as well as finite state VQs for image/video coding. In the tree-search VQ, multiple candidates are identified for ongoing search to optimally determine an index of the minimum distortion. In addition, the desired codebook has been reorganized hierarchically to meet the concept of multipath search of neighboring trees so that picture quality can be improved by 4 dB on the average. In the finite state VQ, adaptation to the state codebooks is added to enhance the hit ratio of the index produced by the tree-search VQ. Thus, compressed bits can be further reduced. An identifier code is then included to indicate to which output indexes belong. Therefore, this modified algorithm not only reaches a higher compression ratio, but also achieves better quality compared to conventional finite-state and tree-search VQs. Finally, suitable VLSI architectures for real-time performance are proposed here (1) to remove the bottleneck of iteration bound in finite-state VQ and (2) to provide parallel computing structure for tree-search VQ to meet computational requirements