Abstract: In order to save the intra coding time of the high efficient video coding, this paper proposes a fast mode selection algorithm for intra prediction. By judging the coding unit size, gradient and direction energy is used to predict the candidate mode respectively. The pixel gradient algorithm is used to reduce the calculation of the candidate mode process. And the judgment of direction energy can reduce the number of candidate modes. The experimental results show that the algorithm provides averagely 27.15% reduction of intra coding time compared with the test platform HM13.0, which can reach the goal of reducing the computational complexity and saving the encoding time effectively.

Key words: video coding, intra prediction, candidate mode, pixel gradient, direction energy

摘要： 为了节省高效视频编码（High Efficiency Video Coding，HEVC）中的帧内编码时间，提出一种帧内预测模式快速选择算法，通过判断预测编码单元的大小，分别采用像素梯度和方向强度来预测候选模式，利用像素梯度能减少选择候选模式过程的计算量，而方向强度判断能减少候选模式数量。实验结果表明，提出的算法与测试平台HM13.0的快速算法相比，帧内预测时间平均减少了27.15%。达到了降低计算复杂度的目的，有效节省了编码时间。

关键词: 视频编码, 帧内预测, 候选模式, 像素梯度, 方向强度