# Research on VVC Intra-Frame Bit Allocation Scheme Based on Significance Detection
## 1 Introduction  
With the development and progress of science and technology, digital video has gradually become an important medium for disseminating information. At the same time, access to video information is no longer only dependent on fixed devices, the development of mobile devices such as cell phones and tablet computers has also led to progress in the video industry. Furthermore, the China Internet Network Information Center (CNNIC) in Beijing has determined in its 52 nd China Internet Development Report that the expansion of the Internet is a significant factor in the advancement of the video industry [1]. As of June 2023, the number of Internet users in China reached 1.079 billion, and the Internet penetration rate reached 76.4%. Digital video transmission is in high demand for a variety of purposes, including webcasting, video conferencing, security surveillance, and personal entertainment. With technological innovations, higher resolution [2] videos are gradually used in people's productive lives, so it is especially important to compress the volume of video data more effectively without affecting the content of the video [3]. Video coding and decoding technologies can reduce the cost of video storage and transmission needs while increasing transmission efficiency. To further enhance coding efficiency, expand versatility, and alleviate the strain on the Internet, a succession of global video coding standards have been established, with Versatile Video Coding (VVC) being the most recent iteration of these standards.  
The video transmission bandwidth is usually subject to certain limitations, and bandwidth differences in network communication affect the transmission bitrate of video andvideo reconstruction quality. the relationship between the coded output bitrate and the compressed distortion is mutually constraining and contradictory. To assure the playback quality of video while effectively transmitting data, despite constraints on channel bandwidth and transmission delay, rate control of the video coding process is necessary.  
In past research, [PERSON] et al. [4] proposed the R-\(\lambda\) model based on the Lagrange multiplier \(\lambda\) according to the relationship between rate and distortion, which achieved excellent results and was adopted by the High Efficiency Video Coding (HEVC) standard and carried over to the VVC standard. In the process of rate control in intra-frame mode, front CTUs tend to have lower coding costs due to the absence of inter-frame information as a reference. On the other hand, the last CTU often needs to increase bit cost significantly to reach the target bitrate, resulting in uneven cost allocation for each CTU in intra-frame mode. To address this issue, this research employs two significance detection methods and a complexity calculation method to guide the bit allocation process at the CTU level, achieving a more reasonable allocation of bits.  
The rest of the paper is organized as follows, Section 2 introduces the video coding standards and related work on rate control, respectively; Section 3 analyzes the characteristics of existing rate control algorithms in terms of bit allocation and proposes an optimization scheme for bit allocation based on significance detection; Section 4 shows the experimental results and analyzes them; and finally, it concludes the work as well as proposes further optimization schemes.