Design And Optimization Of Cross Random Access Point Reference Coded Video Storage And Transmission

In applications that support random access,one video is divided into multiple independently decoded random access segments by multiple random access points.Therefore,the video frames in a random access segment cannot reference to the video frames in other random access segments,which means that the temporal correlation among similar random access segments cannot be effectively used.Some researchers have proposed cross random access point reference video codec technology,which can greatly improve the coding performance by using the correlation between similar random access segments.However,the former research goal is mainly to explore the principle of the technology,and only consider the ideal transmission scheme.In the actual application scenario,there will be the situation that the system layer can not obtain the reference information efficiently,the file format can not describe the reference information,and the multiple transmission of library pictures in the transmission system can not be reused.It is necessary to put the cross random access point reference codec into operation In practical application,we need to further design and optimize the end-to-end transmission in practical application,so this paper studies and optimizes the storage and transmission of cross random access point reference video codec technology.Firstly,to solve the problem that the system layer can not get the reference information efficiently,this paper designs a new supplemental enhancement information to describe the cross random access point reference codec reference information.Thanks to the exclusive start code of supplemental enhancement information,the system layer can directly decode the start code of supplemental enhancement information without decoding the sequence header,so that it can quickly extract the required reference information without decoding too many syntax elements.At the same time,on this basis,this paper also discusses the scheme of system layer splicing the coding stream according to analysising supplementary enhancement information,which enhances the applicability of cross random access point reference codec.Then,aiming at the problem that the conventional file format can not describe the reference information of cross random access point reference codec,this paper proposes three methods based on timed metadata,auxiliary information and sample group,which are used to describe the dependent auxiliary information of hint track samples,and the advantages and disadvantages of the three methods are compared.Considering that the system layer can quickly analyze the reference information and keep the independence and flexibility of knowledge layer data,the method based on sample group is adopted to make the file format be able to describe the reference information of cross random access point reference coding media dataFinally,in order to solve the problem that the library picture can not be reused in the transmission system,this paper improves the traditional transmission system,extends the syntax of MMT(MPEG multimedia transport),we also add a dependency syntax in hint sample to describe the long-term storage characteristics of cross random access point reference video coding media data in the composition information.In addition,the MMT receiver analyzes the above dependency information to count the usage times of the library picture in the package,adds the long-term memory of the library picture and determines the replacement sequence according to the usage times,so as to minimize the repeated downloading of the same knowledge layer data.In this paper,a model of the transmission efficiency of the long-term memory size of the library picture at the receiving end is proposed to guide the long-term memory size setting of the library picture at the receiving end.Based on this model,we can evaluate that under the improved MMT transmission system,the transmission of cross random access coding data can maintain 15% of the 17.2% performance of the ideal transmission,which proves the great potential of cross random access point reference video coding in push streaming media services.Through the research and optimization of the above three aspects,this paper improves the design of cross random access point reference codec system,so that the cross random access point reference codec scheme can maintain the high coding efficiency obtained by the coding layer in the system layer transmission.The above improved cross random access point reference video codec technology has been adopted by the new generation of domestic video coding standard AVS3,which promotes the practical application of the technology.