Waveform Interpolation in Speech Coding

Speech Compression

“…If this conclusion is not evident from this paper alone, the reader is encouraged to review References [1][2][3]11,17,18,35,44]. A second conclusion is that standards activities have been the primary drivers of speech coding research during this time period [3,11,35].…”

“…Johnston [43] performed experiments that estimated the perceptual entropy required for transparent coding of narrowband speech to be about 10 kbit/s on the average up to a maximum of about 16 kbits/s. See also [44]. Given the wide range of these bit rates and since these are all estimates of the bit rate needed for a representative bandwidth or averaged over a collection of speech utterances, they do not provide an indication of the minimum bit rate needed to code a specific given utterance subject to a perceptually meaningful distortion measure.…”

Speech Modification for More Regularity and Pitch Estimation Improvement

“…1(a), a voiced residual speech whose pitch period evolves non-linearly is shown. We apply the procedure in [1] to obtain the pitch values. In Fig.…”

“…For instance, Waveform Interpolation (WI) encoders require the pitch period at every extraction point in order to perform Characteristic Waveform (CW) extraction. In WI decoding, a pitch value at every sample point is required to construct a phase track, and then to convert a two-dimensional surface to a one-dimensional signal [1]. In Mixed Excitation Linear Prediction (MELP), the voicing level of speech is calculated by using the estimated pitch and the normalized autocorrelation value for five frequency bands [2].…”

“…In the first experiment, the effect of the incorrectly estimated pitch values in a WI coder is studied. The CWs are extracted every 2ms with lengths given by the intermediate pitch values [1]. In Fig.…”