Reaserch On QoE Assessement For Videophone Services

With the innovation of the wireless network technology and the improvement of performance for mobile terminal equipment,videophone has become popular.Meanwhile,the user's requirement for the experience of videophone service gradually becomes higher as well.In recent years,virtual reality has attracted much attention because of its good immersive experience.As a potential development trend of social networking,a novel service for VR-voice call is proposed and a VR-voice call system is designed and constructed in this thesis.Targeting the videophone and VR-voice call service,the impact of delay on the quality of the user experience is analyzed and two objective models are proposed to evaluate user experience.It is significantly important to enhance the user experience and promote the rapid development of virtual reality.Due to the high real-time requirements of videophone service,delay is an important factor affecting user's experience.Considering the difference of the arrival time of the audio stream and the video stream,the transmission delay should be divided into two categories,namely,the asynchronous delay and the interaction delay.In addition,the asynchronous delay includes two cases,e.g.,audio arriving earlier than video,and video arriving earlier than audio.By designing subjective experiments,the relationship between asynchronous delay or interaction delay and user experience quality is analyzed.Then,an objective model for predicting the quality of user experience is proposed combing asynchronous delay and interaction delay,respectively.The experimental results show that the performance of the proposed model is better than ITU-T standard G.1070 model.In fact,VR-voice call consists of voice chat and shared panorama video.The factors that affect the quality of user experience are also related to the overall chat experience and immersive sense of viewing panorama video.First,a questionnaire survey is used to study user experience of VR-voice call service from the aspects of overall experience,involvement,attention,reality and physical feelings,respectively.Second,taking into account the influence of speech delay,the relationship between speech delay and quality of user experience is quantitatively studied by the subjective experiment results,and a Qo E evaluation model is proposed.The experimental results show that the proposed model has good performance.