US 12,014,746 B2
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
Emmanuel Ravelli, Erlangen (DE); Manuel Jander, Hemhofen (DE); Grzegorz Pietrzyk, Nuremberg (DE); Martin Dietz, Nuremberg (DE); and Marc Gayer, Erlangen (DE)
Assigned to Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e. V., Munich (DE)
Filed by Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V., Munich (DE)
Filed on Jan. 20, 2022, as Appl. No. 17/580,578.
Application 17/580,578 is a continuation of application No. 15/412,920, filed on Jan. 23, 2017, abandoned.
Application 15/412,920 is a continuation of application No. PCT/EP2015/065219, filed on Jul. 3, 2015.
Claims priority of application No. 14178821 (EP), filed on Jul. 28, 2014.
Prior Publication US 2022/0148609 A1, May 12, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G10L 19/005 (2013.01); G10L 19/022 (2013.01); G10L 19/03 (2013.01); G10L 19/12 (2013.01); G10L 19/20 (2013.01); G10L 19/26 (2013.01); H04B 1/10 (2006.01); G10L 21/0364 (2013.01); G11B 27/038 (2006.01)
CPC G10L 19/26 (2013.01) [G10L 19/005 (2013.01); G10L 19/022 (2013.01); G10L 19/03 (2013.01); G10L 19/12 (2013.01); G10L 19/20 (2013.01); G10L 21/0364 (2013.01); G11B 27/038 (2013.01); H04B 1/1027 (2013.01)] 8 Claims
OG exemplary drawing
 
1. 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.