A novel bit rate reduction method of H.264/AVC intra coding

H.264/AVC intra encoder uses nine prediction modes in 4×4 and 8×8 block unit to reduce the spatial redundancies. Too many intra modes not only increase the encoder complexity but also increase the number of overhead bits. In order to reduce the number of overhead bits and computational cost, an intra mode bit rate reduction (BRR) method is proposed in this paper. In the proposed method, the numbers of prediction modes for each 4×4 and 8×8 block are selected adaptively. Based on the similarities of the reference pixels, each block is classified as one of three categories. This paper also estimates the most probable mode (MPM) from the prediction mode direction of neighboring blocks which have different weights according to their positions. Experimental results confirm that the proposed method saves 12.4% bit rate, improves the video quality by 0.37 dB on average, and requires 37.5% less computations than H.264/AVC intra encoder.