# A Framework for Symmetric-Quality S3D Video Streaming Services
## 4 Results  
### Test Condition and Experimental Method  
The test video consists of two UHD animation sequences and one UHD live-action sequence, each divided into four sections. Each section is determined based on SI (Space Perceptual Information) values of 50, 100, 150, and 200, obtained in accordance with the ITU-T P910 recommendation [22]. SI is an indicator representing the spatial complexity within a video frame, and it measures the degree of edge and texture variation in the frame to calculate the SI value. The SI value is derived by calculating the spatial rate of change in each frame using a Sobel filter and then selecting the maximum value from the grayscale image. A low SI value (50) indicates a relatively simple scene with few textures or details, while a high SI value (200) represents a scene with highly complex textures and details. Therefore, as the SI value increases, the complexity of the video also increases, resulting in greater encoding complexity.  
The evaluation compares the reconstructed right-view video produced by the proposed coding method with HEVC and Cross-View SHVC codec in terms of _PSNR_, and the sequences used for this evaluation are illustrated in Figure 11 and Table 1.  
The encoding process for the experiment proceeds as follows:  
1. As a reference, HEVC encoding is applied to encode the right-view video of UHD resolution. The QPs used for encoding are set to 30, 32, 34, and 36.
2. As another reference, SHVC encoding with a non-HEVC option is applied to encode the right-view video of UHD resolution. The QPs are the same as HEVC.
3. The proposed coding structure is used. The bitrate for Video Enhancement Information (VEI) is set to 1/5 of the bitrate used for base layer encoding in Cross-View SHVC. SHVC encoding based on the non-HEVC option is performed, using the VEI-reconstructed video as the base layer to generate the enhancement layer stream.  
The reason for setting the QP values in the range of 30 to 36 is well known: to receive a 4 K video, a data rate of 15 Mbps is recommended. When compressed to a target bitrate of 15 Mbps, most frames remain within the QP range of 30 to 36.  
The performance of the proposed method is evaluated using BDBR and BDSNR based on the videos obtained through the three methods [23; 24].  
BDBR (Bjontegaard Delta Bitrate) measures the bitrate difference between two compression algorithms. This value represents the difference in the required bitrate between two compression techniques at a given quality level. In other words, it indicates how much less (or more) bitrate one technique requires compared with another while maintaining the same quality.  
BDSNR (Bjontegaard Delta SNR), on the other hand, shows the quality difference (in terms of SNR) between two compression methods. It measures how much the Signal-to-Noise Ratio (SNR) differs between the two codecs when the bitrate is the same. This metric is used to evaluate the quality of the video after compression.  
Figure 10: Proposed decoding framework schematic diagram.  
These two metrics complement each other. BDBR measures compression efficiency in terms of bitrate, while BDSNR reflects quality differences in terms of the Signal-to-Noise Ratio. By using these two metrics together, one can clearly understand how much a new compression technique improves both in terms of bitrate and quality.