Abstract: To simplify the computational complexity of intra-frame prediction mode selection for AVS，a fast Intra-frame prediction mode selection algorithm is proposed.The algorithm uses the correlation of the best modes of adjacent blocks and all zero block detection.Based on the best modes of adjacent blocks，the mode of the current block is selected，and then if the mode is satisfied with the threshold of early termination，the rest modes will not be searched.The paper presents the formula of threshold to suit all kinds of sequences by lots of experiments.It derives the best 8×8 zero-block detection threshold relating only with the quantization parameter.If the predicated mode is satisfied with the threshold，the rest modes will not be searched.Experimental results show that the coding time of the proposed algorithm is decreased by 15.81%~40.76% with negligible loss of PSNR and increment of bit rate.

Key words: Advanced Audio-VideoCoding/Decoding Standard（AVS）, intra-prediction, mode decision, all zero block detection

摘要： 针对AVS视频编码算法降低计算量问题，结合相邻块最佳模式相关性和全零块检测算法，提出一种快速AVS帧内预测模式选择算法。该算法根据相邻宏块的预测模式预先判别待编码宏块的预测模式，若预测模式符合提前中止阈值则停止对其他模式的搜索。通过大量实验得到了对各种图像序列普遍适用的中止阈值经验公式。推导出仅与量化参数QP有关的最佳8×8全零块判决阈值，在模式搜索过程中若预测模式满足全零块判决阈值，就停止对剩余模式的搜索。实验结果表明，在编码效率相当情况下，帧内预测搜索时间减少了15.81%~40.76%。

关键词: 数字音视频编解码技术标准（AVS）, 帧内预测, 模式选择, 全零块检测