K. Funaki and K. Nakamura (Japan)
Coding and Compression, IP telephone, ITU-T G.711, Packet loss concealment (PLC), LPC analysis synthesis
Recently, the demand of IP telephone is increasing more and more while broadband IP network environment turns to be common. In IP telephone, packet loss occurs due to best effort type of network, as a result, the quality of speech is seriously degraded. Packet loss concealment (PLC) is essential in IP telephone. ITU-T G.711 PLC method is adopted widely because of its small computation and elab orated OLA (OverLap Add) algorithm. However, it some times generates click sounds on the boundary of the frame. This paper proposes the improved method for the ITU-T G.711 PLC using LPC analysis and synthesis. In correct received packet frame decoded PCM speech is analyzed by LPC analysis and residual is calculated and LPC co efficients and residual are stored in buffer. In next packet loss frame, LPC coefficients are predicted by repeating the stored LPC coefficients and residual is predicted by using the G.711 PLC method with the stored residual. The pref erence listening test result demonstrates that the proposed method can perform well for random packet loss of 10, 20, and 30 % than the G.711 PLC.
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