Bandwidth extension of harmonic audio signal

Audio decoder (501) for supporting bandwidth extension, BWE, of an harmonic audio signal, the audio decoder comprising:

• a receiving unit, adapted to receive a plurality of gain values associated with a frequency band b and a number of adjacent frequency bands of band b;
• a determining unit (504), adapted to determine whether a reconstructed corresponding frequency band b′ of a bandwidth extended frequency region comprises a spectral peak;
• a gain applying unit (508), adapted to:
• set a gain value associated with the reconstructed frequency band b′ to a first value based on the received plurality of gain values when the reconstructed frequency band b′ comprises at least one spectral peak, and
• set a gain value associated with the reconstructed frequency band b′ to a second value based on the received plurality of gain values when the reconstructed frequency band b′ does not comprise any spectral peak, wherein the second value is lower than or equal to the first value,
• thus enabling bringing gain values into agreement with peak positions in the bandwidth extended frequency region.

Method performed by a transform audio encoder for supporting bandwidth extension, BWE, of an harmonic audio signal, the method comprising:

• determining (602) a peak energy associated with a frequency band b in an upper part of the frequency spectrum of the harmonic audio signal;
• determining (603) a noise floor energy associated with the frequency band b;
• determining (604) a noise-mix coefficient α associated with the frequency band b based on the determined peak energy and noise floor energy;
• and
• providing (606) the noise-mix coefficient α to a corresponding transform audio decoder.

Audio encoder for supporting bandwidth extension, BWE, of an harmonic audio signal, the audio encoder comprising:

• a determining unit (704), adapted to determine a peak energy and a noise floor energy associated with a frequency band b in an upper part of the frequency spectrum of the harmonic audio signal;
• a noise coefficient unit (706), adapted to determining a noise-mix coefficient α associated with the frequency band b based on the determined peak energy and noise floor energy;
• and
• a providing unit (708), adapted to provide the noise-mix coefficient α to a corresponding transform audio decoder