A preprocessing method for perfect reconstruction WI coding

Waveform interpolation (WI) coding with perfect reconstruction is a promising speech coding method with high-level speech quality. However, for efficient coding several pitch values have to be transmitted per frame to guarantee the required accuracy of the pitch contour. In this paper we propose a preprocessing algorithm which slightly modifies the residual signal such that its pitch period evolves smoothly. With the proposed algorithm efficient coding can be achieved with only one transmitted pitch estimate per frame