Multiple Description Coding and Forward Error Correction Concealment Methods for ACELP Coders in Packet Networks

In Voice over Iternet Protocol (VoIP) applications, paquet loss is major source of speech impairement. This work consists on using packet loss concealment methods based on Multiple Description Coding (MDC) and Forward Error Correction (FEC) to improve speech quality deterioration caused by packet losses for Code-Excited Linear Prediction (CELP) based coders in packet network. We applied our approach to the standard ITU-T G.722.2 standard speech coder to evaluate its performance. The Perceptual Evaluation of Speech Quality (PESQ) and Enhanced Modified Bark Spectral Distortion (EMBSD) tests under various packet loss conditions confirm that the proposed algorithm, namely MDC is superior to the concealment algorithm embedded in the G.722.2. The performance measures demonstrate that the concealment method based FEC is better than interleaving and MDC methods at the expense of extra delay.