A Packet Loss Recovery of G.729 Speech Using Discriminative Model and N-Gram

In a VoIP application, packet losses degrade speech quality. Especially, IP network under a large-scale disaster should cause severe packet losses. We have investigated the relationship between parameter loss and speech quality for G.729 codec. In this paper, we propose packet loss recovery method under severe packet loss condition, where the relationship was modeled by Support Vector Machine (SVM). Compared with the "repetition" method, the proposed method could improve speech quality. When we used both SVM and N-gram for concealing packet losses, we could obtain further improvement of speech quality.