Sliding-window forward error correction using Reed-Solomon code and unequal error protection for real-time streaming video

Forward error correction (FEC) techniques are widely used to recover packet losses over unreliable networks in real-time video streaming applications. Traditional frame-level FEC encodes 1 video frame in each FEC coding window. By contrast, in the expanding-window FEC scheme, high-priority frames are included in the FEC processing of the following frames, so as to construct a larger coding window. In general, expanding-window FEC improves the recovery performance of FEC, because the high-priority frame can be protected by multiple windows and the use of a larger coding window increases the efficiency. However, the larger window size also increases the complexity of the coding and the memory space requirements. Consequently, expanding-window FEC is limited in terms of practical applications. Sliding-window FEC adopts a fixed window size in order to approximate the performance of the expanding-window FEC method, but with a reduced complexity. Previous studies on sliding-window FEC have generally adopted an equal error protection (EEP) mechanism to simplify the analysis. This paper considers the more practical case of an unequal error protection (UEP) strategy. An analytical model is derived for estimating the playable frame rate (PFR) of the proposed sliding-window FEC scheme with a Reed-Solomon erasure code for real-time non-scalable streaming applications. The analytical model is used to determine the optimal FEC configuration which maximizes the PFR value under given transmission rate constraints. The simulation results show that the proposed sliding-window scheme achieves almost the same performance as the expanding-window scheme, but with a significantly lower computational complexity.