关键词: 数字音视频编解码技术标准（AVS）, 帧内预测, 率失真优化（RDO）, 边缘方向直方图

Abstract: In order to reduce the computational complexity of intra-prediction mode decision for AVS（Advanced Video Standard），a fast strategy for intra mode decision based on RDO（Rate-Distortion Optimization） technique has been presented.Edge direction field of the image given by sub-sample method is generated with the Sobel edge operation firstly，and then the best intra-prediction mode conformance with RDO principle is decided according to constructed edge direction histogram，and optimizations are made on luma blocks and chroma blocks respectively.Experimental results show that this proposed algorithm can reduce computational time obviously and enhance speed of AVS coding with slight increment of bit-rate and stable peak signal-to-noise ratio.

Key words: Advanced Video Standard（AVS）, intra-frame prediction, Rate Distortion Optimization（RDO）, edge direction histogram