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

摘要： 为了降低AVS帧内预测模式的计算复杂度，提出了一种率失真优化（RDO）准则下的基于边缘特征的快速帧内预测模式选择算法。利用Sobel算子对亚采样后的图像建立边缘方向场，构建编码块的预测模式直方图，根据预测模式直方图的分布确定率失真优化候选预测模式；并对亮度块和色度块分别优化。仿真结果表明，与原AVS相比，该算法在比特率略有增加和信噪比基本保持不变的条件下，大大减少了计算时间，提高了AVS编码速度。

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