一种基于H.264/AVC的多参考帧快速选择算法

A Fast Multiple Reference Frame Selection Algorithm Based on H.264/AVC

最新的视频编码标准H.264/AVC采用了多参考帧运动估计来提高编码效率,增加的计算量与参考帧数目成正比。实际中,多参考帧对编码效率的提高并不完全依赖参考帧数目,而是与序列特征有关。为避免搜索多余的参考帧,提出一种参考帧选择算法来快速确定当前宏块所需的参考帧。该算法利用序列的纹理特征来判定可能的参考帧数目,然后再根据帧间运动信息和RDO(Rate DistortionOptimization)的单调性进一步确定16×16,8×8和4×4模式的最佳参考帧,其它模式可根据与这3种模式的参考帧选择相关性来自适应确定可能选中的参考帧。实验结果表明,这种算法在保持码率和信噪比几乎不变的同时,能够节省约30%的编码时间。

A reference frame selection algorithm was proposed to fastly determine the reference frames required by the current macroblock, which can avoid redundant reference frames. This algorithm can utilize the texture characteristic of sequence to estimate the possible number of reference frames, and further determine the best reference frame of 16×16, 8×8 and 4×4 modes according to the motion information and the monotony of RDO among different reference frames. So the likely reference frames of other modes may be adaptively chosen according to the correlation of reference frame selection with the above modes. The results showed that it can save about 30% of encoding time while maintaining nearly unchanged PSNR and bit-rate.