高效视频编码中变换跳过模式的快速选择

发布时间：2018-04-09 13:19

本文选题：高效视频编码(HEVC)　切入点：视频编码　出处：《中国图象图形学报》2015年02期

【摘要】：目的新一代高效视频编码(HEVC)标准采用了灵活的块结构和大量新颖的编码工具,有效提高了视频编码效率。变换跳过模式作为一种新增加的模式,可以有效地提高编码效率,但是也显著地增加了编码的复杂度,增加了实时编码应用的难度。因此提出一种针对变换跳过模式的提前剪枝算法。方法通过分析不同率失真代价下是否选择变换跳过模式的残差块的分布情况,最终选取率失真代价的平方根作为阈值,并建立了量化参数与阈值之间的模型。之后可以根据量化参数提前计算得到阈值大小,减少变换跳过模式的编码次数,从而降低变换跳过模式的复杂度。结果由于最终只需要对少量的块进行变换跳过模式编码,并且使用模型得到经验阈值并不会额外增加复杂度,因此能减少编码器的计算复杂度。实验结果表明,与标准编码器相比,该算法对于不同场景的标准测试序列平均峰值性噪比和平均比特率变化都非常小,平均减少了70%的变换跳过模式编码的次数。结论该变换跳过模式的剪枝算法,选取率失真代价的平方根作为阈值,根据本文模型获取不同量化参数下的经验阈值,对是否需要进行变换跳过模式提前判断。实验结果表明,该算法能在保证视频编码质量的前提下有效地降低由于加入变换跳过模式增加的编码复杂度。
[Abstract]:Aim the new generation high efficiency video coding standard adopts flexible block structure and a large number of novel coding tools to effectively improve the efficiency of video coding.As a newly added mode, the transform skip mode can effectively improve the coding efficiency, but it also significantly increases the complexity of coding and makes the application of real-time coding more difficult.Therefore, an early pruning algorithm for the transformation skip pattern is proposed.Methods by analyzing whether to choose the residual block distribution of the skipping mode under different rate-distortion costs, the square root of rate-distortion cost was selected as the threshold value, and the model between quantization parameters and threshold was established.Then the threshold value can be calculated in advance according to the quantization parameters, which can reduce the coding times of the transform skip mode and reduce the complexity of the transform skip mode.The result is that only a small number of blocks need to be transformed and skipped mode coding, and the computational complexity of the encoder can be reduced by using the model to get the empirical threshold without increasing the complexity.Experimental results show that the average peak-to-noise ratio and average bit rate of the proposed algorithm for different scenarios are very small compared with the standard encoder, and the frequency of conversion skipping mode coding is reduced by 70% on average.Conclusion the pruning algorithm of the skipping mode of the transformation selects the square root of the rate-distortion cost as the threshold value and obtains the empirical threshold under different quantization parameters according to the model in this paper and judges whether it is necessary to change the skip pattern in advance.Experimental results show that the proposed algorithm can effectively reduce the coding complexity due to the addition of the transform skip mode on the premise of ensuring the video coding quality.
【作者单位】：北京航空航天大学计算机学院数字媒体北京市重点实验室;北京航空航天大学虚拟现实技术与系统国家重点实验室;
【基金】：国家自然科学基金项目(61272502)
【分类号】：TN919.81

【参考文献】