SPEECH-ADAPTIVE LAYERED G.729 CODER FOR LOSS CONCEALMENTS OF REAL-TIME VOICE OVER IP (WedAmOR4)

Author(s) : Batu Sat (University of Illinois at Urbana-Champaign, United States of America) Benjamin Wah (University of Illinois at Urbana-Champaign, United States of America)

Abstract : In this paper, we propose a speech-adaptive multi-description coding (MDC) scheme for the loss concealments of CELP-coded speech transmitted in real time over IP networks. Based on the ITU G.729 CS-ACELP codec operating at 8Kbps, we design a loss-robust speech-adaptive codec at the same bit rate. Our scheme employs MDC for concealing losses and adapts to dynamic loss conditions that are characterized by the loss rate and the degree of burstiness, while maintaining an acceptable end-to-end delay. By protecting only the most important excitation parameters of each frame according to its speech type, our approach enables more efficient usage of the bit budget. Our scheme delivers good-quality speech with a level of protection similar to full replication under medium loss rates, provides speech quality similar to the standard G.729 under very low loss rates, and outperforms both for low-to-medium loss rates.

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