A Fast and Efficient Intra Mode Decision Algorithm for H.264/AVC

In order to achieve the high compression efficiency, H.264/AVC adopts rate-distortion optimization ( RDO ) technology with full mode search in intra prediction. The computational complexity is so high that it isn´t fit for real time encoding and hardware design. So we proposed a fast and efficient intra prediction algorithm. We choose intra luma 4times4 or intra luma 16times16 based on smooth degree of region, and then we only choose part modes of intra luma 4times4, intra luma 16times16 and intra chroma 8times8 based on direction gradient of pixels. Experimentation shows that our algorithm for intra prediction can save more than 75% of the full search time on average in H.264 with negligible degradation of PSNR and increase of Bitrate.