# Research on VVC Intra-Frame Bit Allocation Scheme Based on Significance Detection
## 4 Results  
### Experimental Condition  
In order to compare the performance of the proposed bit allocation scheme with the default rate control scheme, this experiment is compared with the official encoder VTM14.0 provided by JVET, and all the test sequences need to be tested using the official CTC [31] test standard, and we select the 1 st frame from 6 sequences with different scenarios, resolutions, and content richness to be tested under the all intra mode, and the detailed information of each test sequence is shown in Table 4.  
Widely used quality evaluation metrics in video coding are Bjontegaard-Delta rate (BD-rate), Peak Signal-to-Noise Ratio (PSNR), and BD-PSNR. BD-rate denotes the rate increase in the optimized algorithm compared to the original algorithm for the same objective quality of the video, and a negative value indicates that the coding performance of the optimized algorithm has been improved. PSNR is an evaluation standard for video quality by calculating the average of the sum of squared errors of each pixel of the original and compressed videos and converting it to logarithmic form in dB, which is often used for comparing the performance of different compression algorithms and evaluating the quality of the compressed video. In general, the higher the PSNR value, the higher the similarity between the compressed video and the original video, and the better the video quality. The PSNR is calculated as shown in (11) and (12). \[MSE=\frac{1}{mn}\sum_{i=0}^{m-1}\sum_{j=0}^{n-1}\ \parallel I(i,j)-K(i,j)\parallel^{2} \tag{11}\]  
\[PSNR=10\cdot\log_{10}\left(\frac{MAX_{I}^{2}}{MSE}\right)=20\cdot\log_{10} \left(\frac{MAX_{I}}{\sqrt{MSE}}\right) \tag{12}\]  
where \(I(i,j)\) and \(K(i,j)\) are the pixel values of each pixel point of the original and reconstructed images, respectively. \(MSE\) defines the mean square error of the two images and \(MAX_{I}\) denotes the maximum value of the pixel value of each pixel point of the image. BD-PSNR evaluates coding effectiveness by comparing the PSNR values of different coding schemes at the same bit rate. A lower BD-PSNR value indicates that one coding scheme is more efficient compared to the other. The BD-PSNR is calculated as shown in (13). \[BD-PSNR=10\cdot log_{10}\left(\frac{R_{old}}{R_{new}}\right) \tag{13}\]  
where \(R_{old}\) is the PSNR of the original video and \(R_{new}\) is the PSNR of the reconstructed video. In addition to this, another important metric in rate control is the rate control \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Sequences** & **Resolution** & **Frame Number** & **Frame Rate** & **Bit Depth** & **Number of CTUs per Frame** \\ \hline PeopleOnStreet & 2560 \(\times\) 1600 & 300 & 30 & 8 & 260 \\ BasketballDrive & 1920 \(\times\) 1080 & 500 & 50 & 8 & 135 \\ BQMall & 832 \(\times\) 480 & 600 & 60 & 8 & 28 \\ Raciformes & 416 \(\times\) 240 & 300 & 30 & 8 & 8 \\ FourPeople & 1280 \(\times\) 720 & 300 & 60 & 8 & 60 \\ BasketballDrillText & 832 \(\times\) 480 & 500 & 50 & 8 & 28 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Detailed information about the test sequence. Figure 8 shows the difference in bit allocation for each CTU in the six test sequences compared to the pre-adjustment one, using the black dashed line. The horizontal coordinate in the figure is the CTU serial number and the red solid line is Y = 0. This is used to see whether the bit cost is enhanced or weakened for the adjusted CTUs compared to the default algorithm. In the figure, it can be clearly observed that, through the joint guidance of the two significance detection algorithms and a complexity calculation method, and excluding the influence of image noise, only when the significance and complexity are within the limit boosted, it makes the allocation of the bit cost of the \"really important\" CTUs more even