Low-delay vector excitation coding of speech at 16 kb/s

Two kings of pitch predictors in speech compressing coding

“…The normalized residual signal obtained by two cascade predictors approximately tend to standard Gaussian distribution. Now, the long-time predictor(pitch predictor) is always used to ensure the speech quality in some of medium and low bit rate speech coding, such as, 16Kb/s LD-CELP [2], 8Kb/s VSELP [3], 13Kb/s RPE-LTP [ 4] and 4.8Kb/s FS1016-CELP [ 5] and so on. At high bit rate, the sufficient bits can be distributed to excitation so as to guarantee their reconstructed harmonic structure, where the long-time predictor tends to an exact model.…”