Efficient Quality-Based Playout Buffer Algorithm

Abstract: Playout buffers are used in VoIP systems to compensate for network delay jitter by making a trade-off between delay and loss. In this work we propose a playout buffer algorithm that makes the trade-off based on maximization of conversational speech quality, aiming to keep the computational complexity lowest possible. We model the network delay using a Pareto distribution and show that it is a good compromise between providing an appropriate fit to the network delay characteristics and yielding a low arithmetical complexity. We use the ITU-T E-Model as the quality model and simplify its delay impairment function. The proposed playout buffer algorithm finds the optimum playout delay using a closed-form solution that minimizes the sum of the simplified delay impairment factor and the loss-dependent equipment impairment factor of the E-model. The simulation results show that our proposed algorithm outperforms existing state-of-the-art algorithms with a reduced complexity for a quality-based algorithm.