Processing of audio signals during high frequency reconstruction

Abstract

The application relates to HFR (High Frequency Reconstruction / Regeneration) of audio signals. In particular, the application relates to a method and system for performing HFR of audio signals having large variations in energy level across the low frequency range which is used to reconstruct the high frequencies of the audio signal. A system (601, 703) configured to generate a plurality of high frequency subband signals (604) covering a high frequency interval from a plurality of low frequency subband signals (602) is described. The system comprises means for receiving the plurality of low frequency subband signals (602); means for receiving a set of target energies, each target energy covering a different target interval (130) within the high frequency interval and being indicative of the desired energy of one or more high frequency subband signals lying within the target interval (130); means for generating the plurality of high frequency subband signals from the plurality of low frequency subband signals and from a plurality of spectral gain coefficients associated with the plurality of low frequency subband signals, respectively; and means for adjusting the energy (203) of the plurality of high frequency subband signals using the set of target energies.

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