In the video-encoding process

the encoding time is greatly influenced by many factors

such as inter/intra mode decision

motion estimation(ME)

etc. In order to encode the videowith faster speed and beteer quality

this paper only focuses on the intra mode decision in H.264 and presents a fast intra prediction mode decision algorithm for 4×4 blocks in H.264. The proposed algorithm uses: (i) high correlation of RD cost between best prediction mode and its neighborhood prediction mode

(ii) strong correlation between sums of absolute transform differences(SATD) and rate-distortion(RD) performance

efficiently skipping some unlikely prediction modes. Thus

it can complete 4×4 intra prediction by only computing RD cost for four times. The simulation result shows that the proposed algorithm is a good compromise between the coding performance and the encoding speed.