Improved Prediction of Nearly-Periodic Signals

Konferenz: IWAENC 2012 - International Workshop on Acoustic Signal Enhancement
04.09.2012-06.09.2012 in Aachen, Germany

Tagungsband: IWAENC 2012

Seiten: 4Sprache: EnglischTyp: PDF

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Autoren:
Kleijn, W. Bastiaan (School of Engineering and Computer Science, Victoria University of Wellington, New Zealand)
Skoglund, Jan (Google, Inc., 1600 Amphitheatre Parkway, Mountain View, USA)

Inhalt:
We present methods that are relevant for the commonly used pitch predictors in speech/audio coders. We first discuss optimal pre- and post-filtering and derive a general result that post-filtering is more effective than pre-filtering. This, together with the perceived nature of the distortion, suggests the omission of the pre-filter if system delay is critical. We propose a practical paired-zero filter design for the low-rate regime. We extend this design to handle frequencydependent periodicity levels. We also provide a general performance measure for a post-filter that only uses information available at the decoder. This criterion allows the optimization or selection of a postfilter without increasing the rate. Our experiments show that the resulting methods provide state-of-the-art performance both for objective measures and in terms of quality as perceived by test subjects.