基于时空域相关性的屏幕内容帧间快速编码算法

针对屏幕内容视频帧间编码的高复杂度问题，提出了一种基于时空域特性的帧间快速编码算法。首先，根据运动静止检测算法将待编码帧分为静止帧和运动帧；然后，对运动和静止帧分别采用不同的编码策略。对于静止帧，在统计分析时域对应编码单元（CU）分割深度和预测模式的基础上，确定CU最佳分割深度和最优预测模式。对于运动帧中的静止最大编码单元（LCU），利用时域相关特性提前终止CU分割，模式选取则只针对大尺寸模式进行预测；对于运动帧中的运动LCU，根据其相邻LCU的运动静止特性确定CU分割深度以及预测模式。实验结果表明，所提算法相比原始编码平台，在BDBR平均上升3.65%的情况下，编码时间平均节省46.40%。所提算法在率失真性能损失可接受的前提下，有效地降低了屏幕内容视频帧间编码复杂度，有利于屏幕内容视频的实时应用。

Fast inter-frame coding algorithm for screen content based on temporal-spatial correlation

Aiming at the high complexity problem of inter-frame coding for screen content video, a fast inter-frame algorithm based on temporal-spatial correlation was proposed. Firstly, the encoding frames were classified to static frames and motion frames according to motion-static detection algorithm. Then, different encoding strategies were used for motion and static frames, respectively. For the static frames, the optimal partition depth and the optimal prediction mode of Coding Unit (CU) were determined based on the CU partition depth and the prediction mode of the temporal correlation. For the static Largest CU (LCU) in the motion frames, the CU partition was terminated prematurely by using the temporal correlation, and the mode selection was only for the large size modes. Whereas for the motion LCU in motion frames, the motion-static characteristic of adjacent LCU was utilized to determine the current CU partition depth and prediction mode. The experimental results show that the proposed method can reduce the average coding time by 46.40% when BDBR is increased by 3.65% compared with the original coding platform. The proposed method can significantly reduce the complexity of screen content inter-frame encoding process in the premise of negligible BDBR (Bjøntegaard Delta Bit Rate) performance loss. Therefore the proposed method is beneficial to the real-time application of screen content video.