## 5 Subjective QoE Evaluation of Cloud Gaming
### Subjective QoE Results  
The results of the subjective evaluation of cloud gaming QoE were then converted to Mean Opinion Score (MOS) on a 7-point scale and, subsequently, a 5-point scale. The majority of QoS-QoE modelling studies cited in the related work section used a 5-point scale MOS as a barometer for QoE. This is why we opted to convert our 7-point scale QoE data to 5-point scale MOS in order to enable comparisons with studies of a similar nature. Equation (1) presents the equation for rating conversion from a 7-point scale to a 5-point scale. \[Mos_{5}=\frac{4(Mos_{7}-1)}{6}+1 \tag{4}\]  
Figure 5: Spatial and Temporal Information results of cloud games. Figure 6 shows the summary of both the subjective Video-QoE and Game-QoE plotted against different PLR scenarios. The blue line represents the correlated \"Delay-Loss\" scenario, whereas the red line represents the non-correlated scenarios. As expected, MOS of both video-QoE and game-QoE decreased with increasing PLR conditions for all games. Regarding the video-QoE, FIFA was the least affected by the growing PLR, never falling below a MOS of 2 in either correlated or non-correlated scenarios. In both PLR scenarios, the video-QoE of the CSGO and GTA were nearly identical. This could be explained by FIFA's low level of complexity. Since it had the lowest TI and SI, it has the lowest amount of details per frame and was least influenced by PLR. Due to the broadcast camera angle and the video's slow pace, the Parsec platform's packet loss correction algorithm could re-transmit critical data in bit-stream to recover faster, giving it a better QoE score [40]. On the other hand, CSGO was viewed from a First-Person point of view, resulting in faster motion in frames and it being highly affected by packet loss. Since GTA had the highest video quality of all the games, it was also particularly susceptible to poor video-QoE for increasing PLR. More importantly, the subjective results, demonstrated in Figure 6, showed how video-QoE and game-QoE were affected differently by correlated and non-correlated scenarios. In a non-correlated \"Delay-Loss\" QoS scenario, the impact on Video-QoE was greater than in a correlated situation. This could be due to the variations in PLR implementation. NetEm dropped packets at a steady rate in non-correlated conditions, causing all video frames to be affected. As a result, the viewer routinely gave it lower ratings. In correlated conditions, on the other hand, the bursty nature of real-world Internet packet loss was apparent, with regions of high loss and regions of low loss. This caused some portions of the game to have very high video quality, whereas other parts had extremely low video quality. The average evaluation from human subjects showed that people preferred the second scenario over continually poor video quality. However, game-QoE behaved exactly the opposite of video-QoE. The game-QoE was more affected by correlated QoS conditions than non-correlated conditions. This was an interesting finding, as multiple other studies have demonstrated that game-QoE and video  
Figure 6: Subjective QoE Results. QoE are similarly impacted by PLR [15]. However, all those studies ignored any correlation between Delay and Loss metrics. Upon reviewing the survey responses from gamers, it became understandable why this was the case. The most common reason for this outcome was that because PLR was consistent regardless of delay in non-correlated scenarios, players were able to adapt to the stuttering events in the game caused by PLR. Due to the predictability of the gameplay, players were able to complete the game's objective despite the subpar quality of the gameplay. In correlated scenarios, however, players struggled to maintain a sense of predictability since, at times, the gameplay was quite smooth and, at other times, it was extremely difficult with quite a few long-stuttering events. This made it difficult to predict what would happen next, resulting in highly difficult game control and extremely poor MOS ratings.