Improved frame erasure concealment for CELP-based coders

This paper describes new techniques for concealing frame erasures for CELP-based speech coders. Two main approaches were followed: interpolative, where both past and future information are used to reconstruct the missing data, and repetition-based, where no future information is required. Key features of the repetition-based approach include improved muting, pitch delay jittering, and LPC bandwidth expansion. The interpolative approach can be employed in voice over IP scenarios at no extra cost in terms of delay. Applied to the ITU-T G.729 ACELP 8 kb/s speech coding standard, both interpolation- and repetition-based techniques outperform standard concealment in informal listening tests