QoE evaluation of WebRTC-based Mobile Multiparty Video Calls in Light of Different Video Codec Settings

Technological advances in mobile networks and end user devices are paving the way for widespread use of interactive multiparty audiovisual communication services. The emergence of the WebRTC (Web Real-Time Communication) open framework has provided an opportunity to redefine the video conferencing communication landscape. However, in the mobile context, challenges remain in optimizing video encoding parameters due to limited device processing power and dynamic wireless network conditions. In this paper, we investigate how different video encoding parameters in terms of encoding bit rate, resolution, and frame rate, influence Quality of Experience (QoE). While video parameters are manually manipulated, we observe also dynamic video adaptation invoked as a result of the Google Congestion Control (GCC) algorithm. We conduct an experimental study involving twenty-seven users participating in three-party audiovisual WebRTC calls on symmetric mobile devices with a given conversation task to simulate natural conversation. Participants reported subjective ratings for test scenarios with different combinations of video encoding parameters, for which we collect real-time session data using the Chrome WebRTC-internals tool.