This paper presents several multiple description (MD) coding techniques for error mitigation of compressed audio streamed over an 802.11b/g wireless network. Loosely speaking, an MD encoder generates several descriptions of the same source, and an MD decoder recreates the best estimate of the source from the set of descriptions it successfully receives. We propose a design for an MD architecture and simulate its integration into the AAC codec. We use packet loss traces gathered from an actual 802.11 b/g network to simulate the proposed codec’s error mitigation properties for various network traffic conditions. We examine how tuning several of the proposed codec’s parameters would affect the sound quality and overall bitrate of the proposed codec. Specifically, we show how interleaving, renormalization, and low-frequency variance estimation techniques can be used in conjunction with hierarchical correlating transforms to improve the sound quality of multiple description codecs.
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