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Media delivery over lossy packet networks is a challenging problem, and forward error correction (FEC) based techniques are an important technique for overcoming packet loss. Conventional FEC-based media delivery techniques protect all packets equally, or protect a subset of the packets, or protect different subsets of packets with different levels of protection, e.g., scalable coding with unequal error protection (UEP). This paper proposes an FEC-based technique to maximize the expected received media quality by explicitly discarding packets, when beneficial, in order to provide additional room for FEC. Given knowledge of the importance of each packet, we show that there is a simple and intuitive criterion for the optimal selection of which packets to discard and which to protect, as well as the level of protection, to minimize the expected distortion experienced at the receiver. The proposed approach provides significant gains over the conventional approaches, and these gains are illustrated for the case of sending H.264 coded video data over a packet erasure channel with known packet loss rate. |
