An efficient coding method for intra prediction mode information

In H.264/AVC, the bits used for the Intra_4x4 prediction mode information usually occupy a high percentage in intra coding. Towards this issue, we present an efficient coding method for the Intra_4x4 prediction mode information. Firstly, a 3-order Markov random field is introduced to model the correlation among neighboring 4x4 blocks at picture level. Secondly, based on the conditional probabilities learned in this model, we build up a context adaptive coding scheme to code the Intra_4x4 prediction mode information. Although the probabilities and the coding scheme are initialized off-line, they can be revised by automatic adjustments. Thus the proposed algorithm is robust to a variety of video sequences. Experimental results demonstrate that the proposed method can obtain a gain up to 0.3 dB in all I-frames coding without involving any serious computational burden.