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US 12,014,746 B2Granted
Method and apparatus for processing an audio signal, audio decoder, and audio encoder to filter a discontinuity by a filter which depends on two fir filters and pitch lag
AssigneeFraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e. V.
InventorsEmmanuel Ravelli, Manuel Jander, Grzegorz Pietrzyk, Martin Dietz, Marc Gayer
Life of this patent
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Abstract
A method is described that processes an audio signal. A discontinuity between a filtered past frame and a filtered current frame of the audio signal is removed using linear predictive filtering.
Claims8
A method for processing an audio signal, the method comprising:
- filtering audio frames of the audio signal using the following filter:
- H(z)=(1−B(z))/(1−C(z)·z−T)
- where B(z) and C(z) are two FIR filters and the H(z) filter parameters are the coefficients of the FIR filters B(z) and C(z), and T indicates the pitch lag, wherein filtering the audio frames of the audio signal comprises filtering a past frame of the audio signal using a set of first filter parameters for obtaining a filtered past frame, and filtering a current frame of the audio signal using a set of second filter parameters for obtaining a filtered current frame, and
- removing a discontinuity between the filtered past frame and the filtered current frame of the audio signal using a linear predictive filter,
- wherein initial states of the linear predictive filter are obtained by filtering a last part of the past frame using the set of second filter parameters.
2 more elements
A non-transitory digital storage medium having stored thereon a computer program product for performing, when run on a computer, a method for processing an audio signal, the method comprising:
- filtering audio frames of the audio signal using the following filter:
- H(z)=(1−B(z))/(1−C(z)·z−T)
- where B(z) and C(z) are two FIR filters and the H(z) filter parameters are the coefficients of the FIR filters B(z) and C(z), and T indicates the pitch lag, wherein filtering the audio frames of the audio signal comprises filtering a past frame of the audio signal using a set of first filter parameters for obtaining a filtered past frame, and filtering a current frame of the audio signal using a set of second filter parameters for obtaining a filtered current frame, and
- removing a discontinuity between the filtered past frame and the filtered current frame of the audio signal using a linear predictive filter,
- wherein initial states of the linear predictive filter are obtained by filtering a last part of the past frame using the set of second filter parameters.
2 more elements
An apparatus for processing an audio signal,
- wherein the apparatus comprises a processor configured to:
- filter audio frames of the audio signal using the following filter:
- H(z)=(1−B(z))/(1−C(z)·z−T)
- where B(z) and C(z) are two FIR filters and the H(z) filter parameters are the coefficients of the FIR filters B(z) and C(z), and T indicates the pitch lag, wherein filtering the audio frames of the audio signal comprises
- filtering a past frame of the audio signal using a set of first filter parameters for obtaining a filtered past frame, and
- filtering a current frame of the audio signal using a set of second filter parameters for obtaining a filtered current frame, and
- remove a discontinuity between the filtered past frame and the filtered current frame of the audio signal using a linear predictive filter,
- wherein initial states of the linear predictive filter are obtained by filtering a last part of the past frame using the set of second filter parameters.
5 more elements
Dependencies are inferred from the claim text.