Abstract: H.264/AVC adopts advanced intra prediction technology to enhance coding efficiency.As a result，the computational load increases drasticallyA fast intra prediction algorithm is proposed in this paper.Take the advantage of MAD and the correlation in temporal domain/spatial domain，it predicts every macroblock before coding，then select between intra4×4(I4) and intra16×16(I16) prediction modes For I4 prediction，compute D(b_x，b_r) between the current block and the reference block，and then judge whether or not skip the process of mode decision.Therefore，coding time will be reduced drastically.Experimental results show that compared to JM10.2，for all intra frames the timesaving in average is about 59.03%; and for IPPP，the timesaving in average is about 22.76%.The bit rate and SNRY are almost invariability.Furthermore，the algorithm is prone to implement on FPGA platform，and can be used in practice.

Key words: video coding, H-264/AVC, intra prediction, RD-optimization, temporal/spatial correlation

摘要： H.264/AVC采用先进的帧内预测技术，进一步提高了编码效率，但计算复杂度也随之增高。提出了一种快速的帧内预测算法。该算法充分利用宏块的MAD信息及时间/空间相关性，对宏块进行预判，在帧内4×4（I4）和帧内16×16（I16）预测模式之间进行选择；然后，针对I4预测，计算当前块与参考块之间的相似程度D(b_x，b_r)，据此判断是否跳过当前块的模式选择过程，从而减少了编码时间。实验表明，与JM10.2相比，针对全I帧测试：编码时间平均减少约59.03%；针对IPPP测试：编码时间平均减少22.76%；SNRY和码率基本不变。并且，该算法有利于在硬件平台(FPGA)上实现，可用于实际的视频通信产品。

关键词: 视频编码, H-264/AVC, 帧内预测, 率失真优化, 时间/空间相关性