Pitch post-filter

摘要

Methods and systems for using pitch predictors in speech/audio coders are provided. Techniques for optimal pre- and post-filtering are presented, and a general result that post-filtering is more effective than pre-filtering is derived. A practical paired-zero filter design for the low-rate regime is proposed, and this design is extended to handle frequency-dependent periodicity levels. Further, the methods described provide a general performance measure for a post-filter that only uses information available at the decoder, thereby allowing for the optimization or selection of a post-filter without increasing the rate.

主权项

1. A method for determining parameters of a post-filter for a segment of decoded audio, the method comprising:
applying a post-filter to a segment of decoded audio; decomposing signal error for the segment of decoded audio into a signal-correlated distortion component and a signal-uncorrelated noise component; and evaluating a criterion that weighs an increase of the signal-correlated distortion component against a reduction in the signal-uncorrelated noise component.