Verification of Video Quality Opinion Model for Videophone Services

We propose a computational opinion model for estimating the video quality of videophone services. Although opinion models for speech such as the E-model have been established and widely used, little attention has been given to opinion models for video quality estimation. Our proposed opinion model is useful as a network-planning tool using several video parameters that affect the quality of videophone services. First, we established a function for estimating video quality affected by coding distortion, which expresses the quality of a video affected by coding bit rate and frame rate. Second, we established a packet loss degradation index that estimates the degree of video quality degradation due to packet loss. Third, we integrated these two functions into the opinion model for estimating video quality. We applied this model for video quality estimation of H.264 codec. The results indicated that the estimation errors of our model were less than the mean of the 99% confidence intervals for the subjective scores, which is the statistical reliability of subjective score. Finally, we conducted a verification test of our proposed model using an MPEG-4 codec and found that the form of our proposed model was valid, because video quality can be accurately estimated. Therefore, our model could be applied to effective design, implementation, and management of videophone applications and communication networks.