## 5 Experimental Results and Discussion
### Performance Evaluation and Analysis
#### 5.3.3 Decoding-Complexity Reduction and the Impact on Video Quality
First, the use of more accurate and detailed decoding-complexity estimation models enables the encoder to estimate the decoding-complexity requirements for a given coding mode. Next, the proposed decoding-complexity-rate-distortion model allows the encoder to determine the impact of a coding mode on all three parameters. Finally, the continuous update of the decoding-complexity-rate-distortion model allows the encoder to pick the most content-relevant  
\begin{table}
\begin{tabular}{l c c c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Proposed L2**} & \multicolumn{2}{c}{**Proposed L2 \({}^{*}\)**} & \multicolumn{2}{c}{**[PERSON] et al. [20]**} & \multicolumn{2}{c}{**[PERSON] et al. [46]**} & \multicolumn{2}{c}{**[PERSON] et al. [34]**} \\  & \multicolumn{2}{c}{**(Model Only)**} & \multicolumn{2}{c}{**(Model + LF [34])**} & \multicolumn{2}{c}{**(PUM + DBLK)**} & \multicolumn{2}{c}{**(MC + LF)**} \\ \cline{2-13}
**Sequence** & \(\mathbf{\Delta(\text{dB})}\) & \(\mathbf{\Delta\%\uparrow Y}\) & \(\mathbf{\Delta}\) & \(\mathbf{\Delta\Gamma\%\downarrow Y}\) & \(\mathbf{\Delta(\text{dB})}\) & \(\mathbf{\Delta\Gamma\%\downarrow Y}\) & \(\mathbf{\Delta(\text{dB})}\) & \(\mathbf{\Delta\Gamma\%\downarrow Y}\) & \(\mathbf{\Delta(\text{dB})}\) & \(\mathbf{\Delta\Gamma\%\downarrow Y}\) & \(\mathbf{\Delta(\text{dB})}\) & \(\mathbf{\Delta\Gamma\%\downarrow Y}\) \\  & & \multicolumn{2}{c}{**(dB)**} & \multicolumn{2}{c}{**(dB)**} & \multicolumn{2}{c}{**(dB)**} & \multicolumn{2}{c}{**(dB)**} & \multicolumn{2}{c}{**(dB)**} & \multicolumn{2}{c}{**(dB)**} & \multicolumn{2}{c}{**(dB)**} & \multicolumn{2}{c}{**(dB)**} \\ \hline Band & \(-0.89\) & \(-9.97\) & \(-2.09\) & \(-136\) & \(-16.74\) & \(-2.78\) & \(-0.46\) & \(-7.11\) & \(-9.37\) & \(-3.00\) & \(-15.24\) & \(-13.6\) & \(-2.38\) & \(-15.33\) & \(-2.58\) \\ Beergarden & \(-1.26\) & \(-7.12\) & \(-3.88\) & \(-2.01\) & \(-14.14\) & \(-4.86\) & \(-4.05\) & \(-9.63\) & \(-9.15\) & \(-2.56\) & \(-15.88\) & \(-2.85\) & \(-3.41\) & \(-13.40\) & \(-3.93\) \\ Cafe & \(-2.01\) & \(  
trade-off factors when selecting the coding modes that minimize the distortion while achieving the given rate and decoding-complexity constraints. As observed from Figure 4, the proposed algorithm allows the encoder to generate bit streams that provide the least quality impacts on a given decoding-complexity. Moreover, the proposed algorithm is highly scalable and provides the capability to generate bit streams with multiple bit rate and decoding-complexity levels--a crucial benefit for adaptive video streaming services that target streaming videos to mobile devices. For instance, in this case, the decoding-complexity level L2 (i.e., 40% decoding-complexity reduction with respect to HM16.0) results in on average \(-12.71\%\) decoding-complexity reduction when using the openHEVC decoder. Finally, if the bit streams generated by the proposed algorithms are decoded with a decoder that skips the in-loop filter operations (e.g., openHEVC), it can be observed that decoding-complexity can be further reduced by \(\approx 7\%\), with only a minor impact on the video quality. Thus, it is evident that the bit streams generated by the proposed algorithm can be subjected to decoder modifications such as [34] to attain further complexity reductions. Figure 4 also demonstrates the decoding-complexity reduction that can be achieved for a 1 dB quality loss in PSNR. It can be observed that the proposed algorithm on average achieves a greater \(\widehat{\Delta\Gamma}(\%/\mathrm{dB})\) across all bit rates. This is much larger for the proposed algorithm at lower bit rates, due to the reduced quality impact with respect to the HM encoded bit stream. Thus, it is apparent that the proposed algorithm can produce more decoding-complexity reduction than state-of-the-art algorithms for each 1 dB quality loss. Finally, Figure 5 illustrates the visual quality impact of the video sequences reconstructed from the bit streams encoded by HM16.0, the proposed algorithm, and other state-of-the-art methods.