Spectral envelope modelling for full-band speech coding

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Volume Title

Sähkötekniikan korkeakoulu | Master's thesis

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Mcode

S3019

Language

en

Pages

9+61

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Abstract

Speech coding considering historically narrow-band was in the latest years significantly improved by widening the coded audio bandwidth. However, existing speech coders still employ a limited band source-filter model extended by parametric coding of the higher band. In this thesis, a full-band source-filter model is considered and especially its spectral magnitude envelope modelling. To match full-band operating mode, we modified, tuned and compared two methods, Linear Predictive Coding (LPC) and Distribution Quantization (DQ). LPC uses autoregressive modeling, while DQ quantifies the energy ratios between parts of the spectrum. Parameters of both methods were quantized with multi-stage vector quantization. Objective and subjective evaluations indicate the two methods used in a full-band source-filter coding scheme perform on the same range and are competitive against conventional speech coders requiring an extra bandwidth extension.

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Supervisor

Alku, Paavo

Thesis advisor

Bäckström, Tom
Fuchs, Guillaume

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