Device and method for bandwidth extension for audio signals

摘要

The purpose of the present invention is to more efficiently extend, using a low bit rate, the bandwidth of input signals having a harmonics structure, in order to obtain better audio quality. The present invention is installed in a device that extends bandwidth for audio signal encoding and decoding. This novel bandwidth extension encoding identifies a low-frequency spectrum component having the highest correlation to a high-frequency bandwidth signal among input signals, duplicates a high-frequency spectrum by energy adjustment of said component, and maintains the harmonic relationship between the low-frequency spectrum and the duplicated high-frequency spectrum by adjusting the spectral peak position of the duplicated high-frequency spectrum, on the basis of a harmonic frequency estimated from a composite low-frequency spectrum.

主权项

1. An audio signal decoding apparatus, comprising:
a demultiplexer that demultiplexes low-band encoding parameters, index information, and scale factor information from encoded information transmitted from an encoding apparatus that encodes an audio signal; a low-band decoder that decodes the low-band encoding parameters to obtain a synthesized low frequency spectrum; a spectrum replicator that replicates a high frequency subband spectrum based on the index information using the synthesized low frequency spectrum; a spectrum envelope adjuster that adjusts an amplitude of the replicated high frequency subband spectrum using the scale factor information, a harmonic frequency estimator that estimates a frequency of a harmonic component in the synthesized low frequency spectrum; a harmonic frequency adjuster that adjusts a frequency of a harmonic component in the high frequency subband spectrum using the estimated harmonic frequency spectrum; and an output that generates an output signal using the synthesized low frequency spectrum and the high frequency subband spectrum.