Perceptually Unequal Packet Loss Protection by Weighting Saliency and Error Propagation
We describe a method for achieving perceptually minimal video distortion over packet-erasure networks using perceptually unequal loss protection (PULP). There are two main ingredients in the algorithm. First, a perceptual weighting scheme is employed wherein the compressed video is weighted as a function of the nonuniform distribution of retinal photoreceptors. Secondly, packets are assigned temporal importance within each group of pictures (GOP), recognizing that the severity of error propagation increases with elapsed time within a GOP. Using both frame-level perceptual importance and GOP-level hierarchical importance, the PULP algorithm seeks efficient forward error correction assignment that balances efficiency and fairness by controlling the size of identified salient region(s) relative to the channel state. PULP demonstrates robust performance and significantly improved subjective and objective visual quality in the face of burst packet losses.