Method and apparatus for coding of intra prediction mode

Abstract

Embodiments according to the present invention configure the intra prediction mode candidates into multi-level MPM sets, which comprise at least a first-level MPM set and a second-level MPM set. Encoding or decoding a current intra prediction mode is based on the multi-level MPM sets, where one syntax element of the syntax information to be generated or decoded respectively is associated with evaluating the current intra prediction mode using the first-level MPM set. A method and apparatus for chroma intra prediction mode encoding and decoding are also disclosed. The chroma intra prediction mode set includes a Luma-based chroma prediction Mode (LM), a Direct Mode (DM) and four other modes. The codeword set comprises variable-length codewords and fixed-length codewords, and the fixed-length codewords are longer than the variable-length codewords. The variable-length codewords are used for the DM and LM, and the fixed-length codewords are used for the four other modes.