编码质量与容错性自适应的跳帧视频转码

Frame skipping video transcoding based on adaptation of both encoding quality and error resilience

为了使跳帧视频转码在有较好编码质量的同时兼顾转码后新码流的容错性,研究了一种编码质量与容错性自适应的跳帧视频转码方法。提出了基于最优编码质量的跳帧转码算法,依据质量影响系数,在所设计的滑动窗结构中进行了最优跳帧方案的选择,即计算各种跳帧可能性对编码质量的影响,最大程度地保留并编码运动强度较大的帧,提升编码质量。基于此算法,估计跳帧后的错误敏感度和错误影响系数,进一步提出了编码质量与容错性自适应的跳帧方法,使压缩效率和容错能力之间达到动态平衡。实验结果表明：丢包传输时,本方法可使再次解码视频的PSNR值提高0.05~1.2 dB,从而满足跳帧视频转码对帧率准、质量好、容错性强等方面的要求。

In order to balance the encoding quality and error-resilience after video transcoding,a frame skipping video transcoding method based on the adaptation of both encoding quality and error resilience was researched.Firstly,a frame skipping transcoding algorithm based on the optimum encoding quality was introduced,in which the best frame skipping approach in a sliding window was selected based on a quality impact index.That means the method is to calculate the impacts of different frame skipping approaches on the coding quality and to preserve and encode the frames with larger motion intensities to improve the encoding quality.Following this frame skipping algorithm,the error sensitivity and the error impact index due to the frame skipping were also calculated and evaluated,then a frame skipping method based on the adaptation of both encoding quality and error resilience was presented to implement the dynamic balance between the coding efficiency and the error-resilient capability.Extensive experiments prove that the Peak Signal Noise Ratio（PSNR） of re-decoded video can be improved by 0.05-1.2 dB with the proposed method when the data transmittion is with packet losses.For mobile systems and devices,the proposal can meet the needs of accurate frame rate,good quality,and good error resilience.