镜头分割在H.264视频压缩编码及视频服务器中的应用

将镜头分割引入H.264编码端,改善其定比率分配帧类型策略,以针对视频内容特性提高编码效果,并提供压缩流的镜头句柄.提出结合时空切片的信息熵度量帧差、以动态阈值探测镜头边界指定为I帧,非边界帧为P或B帧优化编码,并补充闪光灯防误判算法.经验证动态阈值和熵度量法查全查准率比基本方法提高近18%和13%;结合编码psnr提高10%压缩率提高20%.镜头分割准确,有效提高编码性能,对压缩域视频分割和视频服务器也将产生重大意义.

Shot Segmentation Idea and Algorithm Using in H.264/AVC Video Coding

To alternating the strategy that assign frame type with fixed rate to improve encoding effect by using video's or shot's characters,and providing shot syntax handle on coded video stream,we introduce shot detection method into H.264 codec.Special-temporal slices together with information entropy theory were used to measure frame difference,and statistical-based automatic threshold was used to cut video into shots.Then,shots' edges were assigned as I frame,while the others as P or B frame to optimize the code.We discussed the way to avoid interference of flashlight further.The automatic threshold and entropy measurement gain about 18% and 13% improvement on the recall and precision rate than basic method,and 10% more PSNR when coding rate improving 20%.The algorithm was tested exact on shot detection,and effective on improving encoding performance.It is a good support for shot detection on compressed videos and real-time video severs.