Research On Virtual Reality Video Coding Optimization Algorithm

With the development of multimedia technology,a new technology called virtual reality came into being.This technology can provide users with an immersive virtual world simulation system through real-time calculation.The 360-degree video image of virtual reality can represent complete spherical information,which is stored in the stor age medium in the form of two-dimensional data,but it is easy to introduce distortion and pixel redundancy when projecting from spherical data to two-dimensional data.There fore,for a 360-degree video sequence of virtual reality,it is difficult to obtain a satisfac tory effect by directly compressing and encoding using a conventional two-dimensional encoder.How to design a projection method with less distortion and less pixel redun dancy,how to obtain better reconstructed image quality is the focus of research in this field(1)The Lagrangian multiplier misalignment phenomenon optimized by time-domain rate distortion is analyzed.The calculation method of frame-level coding unit and its bits is defined.By analyzing the bit heat map distribution of the time-domain adjacent coding frame,the current adjustment is adjusted.The Lagrangian multiplier of all coding units in the coding frame makes the Lagrangian multiplier of the coding unit approximate the op timal Lagrangian multiplier,optimizes the bit allocation of the coding unit,and improves the coding efficiency(2)The relationship between latitude and effective pixels in the latitude and Ion gitude map is analyzed,and the algorithm model of latitude decision bit allocation is established.The algorithm can allocate reasonable target bits to the coding unit for the effective information of the location of the coding unit in the latitude and longitude pic ture,and the algorithm can bring significant coding performance improvement to the coding of the latitude and longitude picture(3)In-depth study of PID control theory,combined with PID controller and two coding optimization algorithms proposed in this paper,proposed a PID-based VR rate control model,which guarantees the stability of the rate control process through PID controller.A reasonable number of target bits is allocated to each coding unit by using a coding optimization algorithm.A large number of experiments show that the rate control algorithm can meet the needs of different application scenarios,and has good coding performance and control precisionThrough the above research,the bit redistribution algorithm based on bit heat map proposed in this paper can adjust the coding parameters of the current coding unit ac cording to the encoded bit feedback.The test shows that the algorithm achieves certain coding performance gain under low delay coding configuration.The PID-based VR rate control model proposed in this paper can accurately control the output code rate of the code,and at the same time obtain considerable coding performance improvement.The maximum coding unit-level Lagrangian multiplier optimization method proposed in this paper can perform bit allocation for the effective pixels of the coding unit,and achieves significant coding performance improvement compared with the HEVC coding standard platform.At the same time,the maximum coding unit level Lagrangian multiplier opti mization method has been adopted by the AVS2 standard to the reference software.