# Object Detection-Based Video Compression
## 6 Future Works  
Video compression using Supplemental Enhancement Information (SEI) messages may replace the proposed method. Object information is transmitted through an SEI message, but the SEI message should not change the decoder syntax. Therefore, unlike the proposed method, a process such as post-processing is required. That is, since the CU-based QP-control using the SEI message cannot directly be applied to the VTM-8.2 encoder and decoder, the reconstruction block obtained by the VTM-8.2 encoder and that obtained by the CU-based QP-control using the VTM-8.2 encoder are subtracted, and the subtracted (residual) sample values are transmitted by the SEI message for post-processing in the VTM-8.2 decoder. Figure 12 shows the block diagram of the video compression using the SEI message in the decoder. The VTM-8.2 decoder is used to create the reconstruction \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & & \multicolumn{4}{c}{**Random Access (RA)**} & \multicolumn{4}{c}{**All Intra (AI)**} \\ \hline \multirow{2}{*}{**Class**} & \multirow{2}{*}{**Sequence**} & **Average Y** & **Average Cb** & **Average Cr** & **Average Y** & **Average Cb** & **Average Cr** \\  & & **BD-Rate** & **BD-Rate** & **BD-Rate** & **BD-Rate** & **BD-Rate** & **BD-Rate** \\ \hline \multirow{6}{*}{Class B 1080p} & DaylightRoad2 & 0.48\% & 0.74\% & 1.14\% & \(-\)0.17\% & 0.06\% & \(-\)0.15\% \\  & ParkRunning3 & 0.91\% & 1.14\% & 1.15\% & 0.24\% & 0.90\% & 0.95\% \\ \hline \multirow{6}{*}{Class B 1080p} & MarketPlace & 0.61\% & 1.16\% & 0.96\% & \(-\)0.01\% & 1.69\% & 1.14\% \\  & RitualDance & 3.82\% & 4.41\% & 5.20\% & 0.07\% & 0.87\% & 1.37\% \\  & Cactus & 1.77\% & 2.71\% & 2.92\% & 0.95\% & 2.54\% & 2.12\% \\  & BasketballDrive & 3.54\% & 3.96\% & 3.39\% & 1.07\% & 1.34\% & 0.84\% \\ \hline \multirow{6}{*}{Class C  WVGA} & BQTerrace & 0.88\% & 1.08\% & 0.49\% & 0.07\% & 0.33\% & 0.26\% \\  & BasketballDrill & 4.10\% & 3.09\% & 3.32\% & 1.01\% & 0.00\% & \(-\)0.08\% \\ \cline{1-1}  & BQMall & 3.74\% & 3.84\% & 4.13\% & \(-\)0.55\% & 1.21\% & 1.33\% \\ \cline{1-1}  & PartyScene & 2.41\% & 2.27\% & 2.65\% & 1.13\% & 1.68\% & 2.16\% \\ \hline \multirow{6}{*}{Average} & Class A1 & 2.61\% & 3.09\% & 3.50\% & 0.75\% & 2.42\% & 2.01\% \\ \cline{1-1}  & Class A2 & 0.96\% & 1.18\% & 1.21\% & 0.36\% & 1.09\% & 0.66\% \\ \cline{1-1}  & Class B & 2.12\% & 2.66\% & 2.59\% & 0.43\% & 1.35\% & 1.14\% \\ \cline{1-1}  & Class C & 3.40\% & 3.46\% & 3.67\% & 0.83\% & 1.92\% & 1.90\% \\ \cline{1-1}  & All & 2.33\% & 2.67\% & 2.78\% & 0.59\% & 1.66\% & 1.42\% \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._video and the object information in the SEI message shown in Figure 12 is used in the post-processing. The CU-based QP-control using the SEI message increases the complexity due to the VVC encoder having to perform twice as many times. Since the SEI message is not allowed to change the VTM-8.2 bitstream syntax, it needs twice the encoding: the VTM-8.2 encoding and the CU-based QP-control encoding, which is similar to the method proposed in Section 3.2. Since the CU-based QP-control method using the SEI message encodes all the residual samples between the VTM-8.2 reconstruction samples and the CU-based QP-control reconstruction samples to transmit the message in the SEI bitstream, the bitstream size is increased. However, the proposed method encodes the object information once in the feature bitstream. Therefore, the proposed method only has to send information such as the center (x, y) coordinate of each object, the width and height of each object, and the name of each object (object index) obtained from the object detection. In conclusion, the CU-based QP-control using an SEI message may be used in an object-detection algorithm, but the complexity and bitstream size are currently too high. [PERSON] and [PERSON] conceived and designed the experiments; [PERSON] implemented software and performed the experiments; [PERSON] supervised the algorithm; and [PERSON] and [PERSON] wrote the paper.