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Methods, apparatus and systems for determining reconstructed audio signal

  • US 10,529,347 B2
  • Filed: 02/05/2019
  • Issued: 01/07/2020
  • Est. Priority Date: 03/28/2002
  • Status: Expired due to Term
First Claim
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1. A method for generating a reconstructed audio signal having a baseband portion and a highband portion, the method comprising:

  • deformatting an encoded audio signal into a first part and a second part;

    extracting, from the first part, temporal envelope information;

    extracting, from the first part, spectral components of the baseband portion, wherein the spectral components of the baseband portion do not include spectral components of the highband portion and the number of the spectral components of the baseband portion may vary dynamically;

    decoding the first part to obtain a decoded baseband audio signal, wherein the decoding includes filtering in a frequency domain at least some of the spectral components of the baseband portion based on the temporal envelope information to shape a temporal envelope of the baseband portion;

    extracting, from the second part, a noise parameter and an estimated spectral envelope of the highband portion;

    obtaining a plurality of subband signals by filtering the decoded baseband audio signal, wherein the plurality of subband signals are generated with one or more Quadrature Mirror Filters (QMF);

    generating a high-frequency reconstructed signal by copying in a circular manner a number of consecutive subband signals of the plurality of subband signals;

    obtaining an envelope adjusted high-frequency signal by adjusting, based on the estimated spectral envelope of the highband portion, a spectral envelope of the high-frequency reconstructed signal, wherein a frequency resolution of the estimated spectral envelope is adaptive, and wherein the obtaining the envelope adjusted high-frequency signal includes determining and applying a gain;

    generating a noise component based on the noise parameter, wherein the noise parameter indicates a level of noise contained in the highband portion;

    obtaining a combined high-frequency signal by adding the noise component to the envelope adjusted high-frequency signal; and

    obtaining a time-domain reconstructed audio signal by combining the decoded baseband audio signal and the combined high-frequency signal;

    wherein the method is implemented by an audio decoding device comprising one or more hardware elements.

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