On Accommodating Pitch Variation in Long Term Prediction of Speech and Vocals in Audio Coding

Nanjundaswamy T, Rose K. On Accommodating Pitch Variation in Long Term Prediction of Speech and Vocals in Audio Coding. In: AES Convention 133. Audio Engineering Society; 2012. Paper 8767. Available from: https://aes.org/publications/elibrary-page/?id=16509

@inproceedings{Nanjundaswamy2012_16509,
  author = {Nanjundaswamy, Tejaswi and Rose, Kenneth},
  title = {{On Accommodating Pitch Variation in Long Term Prediction of Speech and Vocals in Audio Coding}},
  booktitle = {AES Convention 133},
  note = {Paper 8767},
  year = {2012},
  month = oct,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=16509}
}

TY  - CPAPER
TI  - On Accommodating Pitch Variation in Long Term Prediction of Speech and Vocals in Audio Coding
AU  - Nanjundaswamy, Tejaswi
AU  - Rose, Kenneth
T2  - AES Convention 133
M1  - Paper 8767
PY  - 2012
DA  - 2012/10/06
UR  - https://aes.org/publications/elibrary-page/?id=16509
PB  - Audio Engineering Society
LA  - en
AB  - Exploiting inter-frame redundancies is key to performance enhancement of delay constrained perceptual audio coders. The long term prediction (LTP) tool was introduced in the MPEG Advanced Audio Coding standard, especially for the low delay mode, to capitalize on the periodicity in naturally occurring sounds by identifying a segment of previously reconstructed data as prediction for the current frame. However, speech and vocal content in audio signals is well known to be quasi-periodic and involve small variations in pitch period, which compromise the LTP tool performance. The proposed approach modifies LTP by introducing a single parameter of “geometric” warping, whereby past periodicity is geometrically warped to provide an adjusted prediction for the current samples. We also propose a three-stage parameter estimation technique, where an unwarped LTP filter is first estimated to minimize the mean squared prediction error; then filter parameters are complemented with the warping parameter, and re-estimated within a small neighboring search space to retain the set of S best LTP parameters; and finally, a perceptual distortion-rate procedure is used to select from the S candidates, the parameter set that minimizes the perceptual distortion. Objective and subjective evaluations substantiate the proposed technique’s effectiveness.
ER  -