A Networked Videophone Quality Assessment System

Rapid development of videophone services has created the acute need for quality assessment at network nodes during transmission, to ensure the service quality. Therefore research interests have been focused on real-time, no-reference quality assessment for videophone service with low complexity. ITU-T G.1070 is the state-of-the-art quality planning model for networked videophone, without dealing with the acquirement of the input parameters. In this thesis a networked videophone system is developed based on stream analysis according to G.1070. This system first analyses the RTP/UDP/IP multimedia data stream and acquires the information about the standards and bit-rates for video and audio coding, the packet loss rate and etc. Then the coding bit-rate and the packet loss rate are used to estimate the impact of coding distortion and packet loss on the service quality, providing the audio and video quality. Then the videophone quality is obtained by integrating the audio and video quality. This thesis describes the methods for obtaining the model parameters for the videophone quality assessment system, as well as the parameters for AMR audio coding and MPEG-4 video coding. This system supports real-time capturing of networked data packets, providing a graphic interface for the objective MOS and the comparison with the subjective data for decoding and playing of multimedia streaming.