CONTEXT OPTIMIZATION FOR CODING THE POSITION OF THE LAST SIGNIFICANT COEFFICIENT

摘要

1. A method of encoding transform coefficients for a transform block, comprising: obtaining a binary chain indicating the position of the last significant coefficient within the transform coefficient transform block; determining a context for the binary index of the binary chain based on the size of the transform block, the context being assigned to at least two binary indexes, each of at least two binary indices associated with different sizes of the transform block; binary chain encoding using context adaptive binary arithmetic coding (SAVAS) based on at least partially defined context. 2. The method of claim 1, wherein the context is assigned to each of at least two binary indices in accordance with the context index (ctx_index) defined by the function: ctx_index = (n log (T)) + 15; where n is binary index, and T is the size of the transform block. 3. The method of claim 1, wherein the context is assigned to the last binary index of the 16 × 16 transform block and the last binary index of the 32 × 32 transform block. The method of claim 3, wherein the second context is assigned to adjacent binary indices of the 16 × 16 transform block. The method of claim 1, wherein encoding the binary chain using SAVAS based on at least a partially determined context includes updating the context based on the value of the binary chain, and wherein the conversion unit is a first conversion unit; and which further comprises: obtaining a second binary chain indicating the position of the last significant coefficient within watts