# Data Embedding in SHVC Video Using Threshold-Controlled Block Splitting
## 4 Experimental Results
### Comparison with Conventional Methods
Nonetheless, the proposed technique has the flexibility to embed different amounts of payload by adjusting \(\tau\). When the required embedding capacity is low, \(\tau_{0}\) can be adopted so that the bit rate overhead and distortion can be reduced. On the other hand, more embedding capacity could be achieved by using a larger \(\tau\) so that each CTU can be split into smaller blocks. Note that the total number of smaller blocks in a CTU is determined by the RDC, and it is guided by \(\tau\) so that block-splitting will not be performed when the cost is higher than \(\tau\). Next, we analyze the impact of data embedding on the quality of the video. It is observed that the quality of the video may be affected depending on when (i.e., at which stage) data are embedded within the video encoding process as well as the embedding capacity. For example, when data embedding takes place before the computation of the prediction error/residual such as using intra prediction mode and MV, the residual will be obtained by using the new predicted value; therefore, the quality of the video can be maintained, although the residual is slightly larger. On the other hand, manipulating coding block structure may affect the selection of the optimal prediction block size and prediction mode, which will indirectly cause higher prediction error. Therefore the quality of the video is affected. Similarly, manipulating the transformed coefficients causes the \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multirow{2}{*}{**Sequence**} & \multicolumn{2}{c}{\(\tau_{0}\)} & \multicolumn{2}{c}{\(\tau_{5}\)} & \multicolumn{2}{c}{\(\tau_{10}\)} \\  & [20] & [21] & **Proposed** & [21] & **Proposed** & [21] & **Proposed** \\ \hline _RushHour_ & 11.44 & 12.1 & 22.04 & 46.84 & 81.16 & 145.18 & 222.96 \\ _FourPeople_ & 13.12 & 14.71 & 80.32 & 39.58 & 179.96 & 59.3 & 297.27 \\ _BlueSky_ & 28.63 & 33.88 & 69.18 & 65.01 & 161.98 & 75.34 & 261.31 \\ _BasketballDrill_ & 19.88 & 22.48 & 71.83 & 41.04 & 156.86 & 54.18 & 245.52 \\ _PartyScene_ & 47.76 & 56.53 & 144.87 & 102.78 & 332.51 & 118.92 & 447.22 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison of embedding capacity (kbps) for the LDP configuration. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Sequence** & [30] & [15] & **Proposed** \\ \hline _RushHour_ & 48.58 & 52.22 & 57.81 \\ _FourPeople_ & 180.89 & 285.96 & 346.73 \\ _BlueSky_ & 114.52 & 116.67 & 206.29 \\ _BasketballDrill_ & 141.71 & 171.75 & 281.63 \\ _PartyScene_ & 238.05 & 304.11 & 462.46 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Comparison of embedding capacity (kbps) for the AI configuration. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Functional** & **Embedding** & **Applicable to** & **Embedding** & **Quality after** & **Bit Rate** \\
**Comparison** & **Venue** & **I-Frame** & **P/B Frame** & **Capacity** & **Embedding** & **Overhead** \\ \hline [15; 16; 30; 40] & Intra prediction mode & ✓ & ✓ & H & H & M \\ [19; 20] & MVD & \(X\) & ✓ & L & H & L \\ [23; 24] & Block partition & ✓ & ✓ & H & M & M \\ [25; 31; 39; 41] & Coefficient & ✓ & ✓ & H & M & M \\ [43] & Merge mode & \(X\) & ✓ & M & H & L \\ [22] & Block partition + Coefficient & ✓ & ✓ & H & M & M \\ _Proposed_ & Intra prediction mode + MVP & ✓ & ✓ & H & H & M \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Relative functional comparison of conventional and proposed data embedding techniques within various video coding standards. entire block of pixel values to change. The perceived quality of these two methods will then be affected by the quantization process applied on the prediction residues. Similar findings are observed from related works; for example, the perceptual quality degradation for the intra prediction mode and merge mode is less than 0.2 dB [15; 16; 40] while MVD [19] is less than 0.06 dB. Since the quality degradation is less than 1 dB, which is negligible, therefore we label the quality as 'H'.