1. A system for context-based adaptive binary arithmetic encoding and decoding, the system comprising: a calculating device configured to calculate an index value for a first bin to be encoded or a second bin to be decoded; a memory device configured to store context models in clusters, wherein each cluster is loaded for processing as a single unit and at least one cluster includes multiple context models arranged in an order of syntax element processing, and wherein the index value for the first bin or the second bin is related to one of the context models; and a binary arithmetic unit configured to serve as an encoder for encoding the first bin based on the one context model or a decoder for decoding the second bin based on the one context model.