Band extension method, band extension apparatus, program, integrated circuit, and audio decoding apparatus

摘要

Provided is a bandwidth expansion method capable of reducing the amount of bandwidth expansion computation and suppressing the deterioration in the quality of the expanded bandwidth. In this band extension method, the first low frequency QMF spectrum is generated by converting the low frequency band signal to the QMF region (S11), and the pitch shift is performed by applying different shift coefficients to the low frequency band signal. A plurality of generated signals are generated (S12), and a high frequency QMF spectrum is generated by time-expanding in the QMF region (S13), the high frequency QMF spectrum is corrected (S14), and the corrected high frequency QMF spectrum and The first low frequency QMF spectrum is combined (S15).