基于运动矢量细化的帧率上变换与HEVC结合的视频压缩算法

将帧率变换技术与新型视频压缩编码标准HEVC相结合有利于提升视频的压缩效率。针对直接利用HEVC码流信息中的低帧率视频的运动矢量进行帧率上变换时效果不理想的问题,文中提出了一种基于运动矢量细化的帧率上变换与HEVC结合的视频压缩算法。首先,在编码端对原始视频进行抽帧,降低视频帧率;其次,对低帧率视频进行HEVC编解码;然后,在解码端与从HEVC码流中提取出的运动矢量相结合,利用前向-后向联合运动估计对其进行进一步的细化,使细化后的运动矢量更加接近于对象的真实运动;最后,利用基于运动补偿的帧率上变换技术将视频序列恢复至原始帧率。实验结果表明,与HEVC标准相比,所提算法在同等视频质量下可节省一定的码率。同时,与其他算法相比,在节省码率相同的情况下,所提算法重建视频的PSNR值平均可提升0.5 dB。

Video Compression Algorithm Combining Frame Rate Up-conversion with HEVC Standard Based on Motion Vector Refinement

Combining frame rate conversion technology with the HEVC standard will improve the compression efficiency of video.Aiming at the non-ideal result in frame rate up-conversion using the motion vector of low frame rate video extracted from HEVC coding bit stream directly,this paper proposed a compression algorithm combining frame rate up-conversion and HEVC based on motion vector refinement.Firstly,at the encoding end,the original even frames are extracted to reduce the frame rate of video,and then the low frame rate video is encoded and decoded by HEVC.Combined with the motion vector extracted from HEVC coding bit stream at the decoding end,the forward-backward joint motion estimation is used to further refine it,which makes the motion vector closer to the real motion of the object.Finally,the frame rate up conversion technique based on motion compensation is used to restore the video to its original frame rate.Experimental results show that compared with the HEVC standard,the proposed algorithm has some bitrate saving.In the meantime,compared with other algorithms,the proposed algorithm can increase the PSNR value of reconstructed videos by 0.5 dB on average with the same bitrate saving.