A comparison of warped and conventional linear predictive coding

LP/WLP Hybrid Scheme for Quality Improvement of TCX Coders Operating at Low Bit Rates

“…1, the WLP-based TCX can be efficient for stationary signals in which harmonic components are dominantly distributed in low frequency bands [4]. Therefore, several spatio-temporal parameters such as low-band energy, harmonic distribution, transient information, etc., should be monitored to decide whether the WLP-based TCX scheme would be used or not.…”

“…LP is an effective tool for modeling both speech and audio, so it has been widely used in a variety of speech/audio codecs. For audio signals, especially when the signals are nearly stationary, it was indicated that warped linear prediction (WLP) could be more effective than LP in terms of bit saving [4]. Therefore, perceptual quality could be improved by using WLP rather than LP at the same bit rates.…”

“…However, the resolution of higher-frequency bands is deemphasized compared with LP, which could lead to performance degradation. In this paper, we distinguish between low-and high-bands according to the turning frequency [4].…”

“…Warped linear prediction is obtained by simply replacing the unit delay of linear prediction with an all-pass filter (APF) having a transfer function [4] …”

Robust features for speech recognition using minimum variance distortionless response (MVDR) spectrum estimation and feature normalization techniques

“…In frequency-warped signal processing techniques, the warping process can be achieved by replacing the unit-delay element by a first-order all-pass filter with a transfer function [10][11][8] [9] ),…”