# Two-Dimensional Histogram Shifting-Based Reversible Data Hiding for H.264/AVC Video
## 4 Experimental Results
### File Size  
Generally, the file size of marked videos will increase. However, as the H.264/AVC video aims to provide good video quality at a low bit rate, so it is desirable that the RDH schemes for H.264/AVC video will not cause a significant increase in the file size of marked videos. The experimental results of the schemes using the \((0,0)\) coefficient pairs are shown in Figures 7 and 8. It can be seen from Figure 7 that when QP is 16, the increase in file size caused by our scheme is apparently smaller than that of [33] for all six videos. Although the increase in the file size of marked video generated by [34] is close to ours, it is still slightly higher, and as the payload increases, the difference become more noticeable. When QP is 28, Figure 8 shows that the file size increase of our scheme is also apparently lower than that of [33]. However, the difference between our scheme and [34] is very small. The reason for the above results is that the method proposed in [33] uses only half of the plane, resulting in more blocks of H.264/AVC video modified with the same payload. Although both values of the points that will be shifted by [34] need to be modified at the same time during data embedding, we found that these points are seldom used in our experiments because the \((0,0)\) coefficient pairs carry most of the payload, so the file size increase of [34] is close to that of ours. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**QP = 16**} & \multicolumn{6}{c}{**QP = 28**} \\ \cline{2-13}
**Video** & \multicolumn{6}{c}{**PSNR (\%)**} & \multicolumn{6}{c}{**SSIM (\%)**} & \multicolumn{6}{c}{**PSNR (\%)**} & \multicolumn{6}{c}{**SSIM (\%)**} \\ \cline{2-13}  & **Ours\({}^{-}\)** & **[37]** & **[29]** & **Ours\({}^{-}\)** & **[37]** & **[29]** & **Ours\({}^{-}\)** & **[37]** & **[29]** & **Ours\({}^{-}\)** & **[37]** & **[29]** \\ \hline High & 73.3 & 0.0 & 26.7 & 96.7 & 6.7 & 56.7 & 83.3 & 10.0 & 13.3 & 96.7 & 66.7 & 76.7 \\ Middle & 26.7 & 0.0 & 73.3 & 3.3 & 20.0 & 43.3 & 10.0 & 10.0 & 73.3 & 3.3 & 13.3 & 23.3 \\ Low & 0.0 & 100.0 & 0.0 & 0.0 & 73.3 & 0.0 & 6.7 & 80.0 & 13.3 & 0.0 & 20.0 & 0.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: The percentages of PSNR and SSIM values of different schemes without using the \((0,0)\) coefficient pairs in each ranking. \begin{table}
\begin{tabular}{l c c c c c c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Shannon Entropy/Shannon Entropy Change**} \\ \cline{2-13}
**Video** & \multicolumn{6}{c}{**QP = 16**} & \multicolumn{6}{c}{**QP = 28**} \\ \cline{2-13}  & \multicolumn{6}{c}{**(0,0)s Are Used (0,0)s Are Used (0,0)s Are Used**} & \multicolumn{6}{c}{**Origin**} & \multicolumn{6}{c}{**(0,0)s Are Used**} & \multicolumn{6}{c}{**(0,0)s Are’t Used**} \\ \cline{2-13}  & **Origin** & **Ours\({}^{+}\)** & **[33]** & **[34]** & **Ours\({}^{-}\)** & **[37]** & **[29]** & **Ours\({}^{+}\)** & **[33]** & **[34]** & **Ours\({}^{-}\)** & **[37]** & **[29]** \\ \hline foreman & 7.402 & 0.013 & 0.014 & 0.014 & 0.004 & 0.006 & 0.005 & 7.381 & 0.006 & 0.009 & 0.005 & 0.000 & 0.000 & 0.000 \\ container & 6.871 & 0.013 & 0.014 & 0.013 & 0.004 & 0.005 & 0.005 & 6.828 & 0.005 & 0.005 & 0.005 & 0.000 & 0.000 & 0.000 \\ bus & 7.316 & 0.010 & 0.012 & 0.014 & 0.007 & 0.011 & 0.008 & 7.286 & 0.030 & 0.032 & 0.030 & 0.004 & 0.006 & 0.005 \\ crew & 7.148 & 0.020 & 0.020 & 0.020 & 0.008 & 0.009 & 0.010 & 7.122 & 0.064 & 0.067 & 0.066 & 0.000 & 0.002 & 0.000 \\ hall\_monitor & 7.269 & 0.006 & 0.014 & 0.009 & 0.003 & 0.005 & 0.005 & 7.244 & 0.001 & 0.003 & 0.002 & 0.000 & 0.000 & 0.000 \\ mobile & 7.568 & 0.004 & 0.005 & 0.004 & 0.000 & 0.001 & 0.000 & 7.603 & 0.000 & 0.000 & 0.000 & -0.001 & -0.001 & -0.002 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Shannon entropy of each cover video and changes in Shannon entropy of the marked video generated by different schemes. The experimental results of the schemes without using the \((0,0)\) coefficient pairs are shown in Figures 9 and 10.