# Efficient Transcoding and Encryption for Live 360 CCTV System
## 4 Performance Evaluation  
### Testbed Scenario  
To demonstrate the operation of the proposed method in a real environment, we implemented a testbed to verify the ability of real-time transcoding and encryption. For experimental measurements, we set up a testbed scenario, as shown in Figure 12. We set up a transcoder box with a Intel(R) Core(TM) i7-7500U 2.70 GHz processor (Intel Corporation, Santa Clara, CA, USA), 16 GB of memory with Linux Centos 64-bits version 3.10.0-862.9.1.el7.x86_64 (gcc version 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC)) OS. We also used mobile virtual reality-based bead-mounted-device, desktop, and laptop as clients in the control center. Additionally, we installed two Hanwa CCTV cameras [27] as 2D cameras and a Samsung 360 camera as 360 CCTV camera. Table 1 shows the standard 360 4K video test sequences in detail. These video test sequences were released by JCT-VC, as shown in Figure 13.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Value** \\ \hline InputFile & DrivingInCity 3840 \(\times\) 1920\_30 fps\_8 bit\_420\_erp.yuv \\ Width & 3840 \\ Height & 1920 \\ \hline InputFile & KiteFlite 4096 \(\times\) 2048\_30 fps\_8 bit\_420\_erp.yuv \\ InputFile & Harbor 4096 \(\times\) 2048\_30 fps\_8 bit\_420\_erp.yuv \\ InputFile & GasLamp 4096 \(\times\) 2048\_30 fps\_8 bit\_420\_erp.yuv \\ InputFile & Trolley 4096 \(\times\) 2048\_30 fps\_8 bit\_420\_erp.yuv \\ SourceWidth & 4096 \\ SourceHeight & 2048 \\ \hline InputBitDepth & 8 \\ InputChromaFormat & 420 \\ FrameRate & 30 \\ FrameSkip & 0 \\ FramesToBeEncoded & 300 \\ Level & 5.2 \\ \hline \hline \end{tabular}
\end{table}
Table 1: The 360 videos bitstreams by JCT-VC.  
Figure 12: Testbed for live CCTV system.  
Regarding software, HM software with 360 libraries [24] was used as video encoder and openHEVC software [28] as video decoder. Intel Media SDK [29] was used to accelerate transcoding by multiple threads. Crypto++ crypto library [30] was used for bitstream encryption/decryption. The hevcbrowser software [31] was used to perform the status of HEVC bitstream. To evaluate performance, ERP Peak Signal-to-Noise Ratio (PSNR) software [32] and FFmpeg were used as estimation tools. Additionally, HM and 360 libraries were used to process a spherical 360 video with ERP projection [33]. The ERP projection is described in detail in Table 11. The encoding configuration parameters of 360 bitstreams are listed in Table 12. The 2D video test sequences were also encoded using HM version 16.15 within standard configurations for 8 bits.  
To evaluate the quality of the output 360 videos, we calculated the distortion in the sphere to properly respond to our view of the 360 videos, instead of calculating the PSNR in rectangle plane. We used PSNR sphere (WS-PSNR) [33] weighted index method for calculating distortion of 360 videos reproduced in the sphere domain to show the difference between the reconstructed video and the original 360 video. The WS-PSNR software [32] provides WS-PSNR calculations for both ERP window and entire ERP system, as shown in Figure 14. To perform performance evaluations for the proposed method, we used a video test sequences as representation data for both 360 CCTV camera and the 2D CCTV camera.