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公开(公告)号：US12119011B2
公开(公告)日：2024-10-15
申请号：US18439631
申请日：2024-02-12
发明人： Lars Villemoes , Per Hedelin
IPC分类号： G10L19/26 , G10L19/02 , G10L21/0388 , G10L25/90
CPC分类号： G10L19/265 , G10L19/02 , G10L21/0388 , G10L25/90
摘要： The present invention relates to audio coding systems which make use of a harmonic transposition method for high frequency reconstruction (HFR). A system and a method for generating a high frequency component of a signal from a low frequency component of the signal is described. The system comprises an analysis filter bank providing a plurality of analysis subband signals of the low frequency component of the signal. It also comprises a non-linear processing unit to generate a synthesis subband signal with a synthesis frequency by modifying the phase of a first and a second of the plurality of analysis subband signals and by combining the phase-modified analysis subband signals. Finally, it comprises a synthesis filter bank for generating the high frequency component of the signal from the synthesis subband signal.
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公开(公告)号：US12094480B2
公开(公告)日：2024-09-17
申请号：US18228109
申请日：2023-07-31
发明人： Lars Villemoes , Heiko Purnhagen , Per Ekstrand
IPC分类号： G10L19/00 , G10L19/008 , G10L19/24 , G10L19/26
CPC分类号： G10L19/26 , G10L19/008 , G10L19/24
摘要： A method for decoding an encoded audio bitstream is disclosed. The method includes receiving the encoded audio bitstream and decoding the audio data to generate a decoded lowband audio signal. The method further includes extracting high frequency reconstruction metadata and filtering the decoded lowband audio signal with an analysis filterbank to generate a filtered lowband audio signal. The method also includes extracting a flag indicating whether either spectral translation or harmonic transposition is to be performed on the audio data and regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata in accordance with the flag.
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公开(公告)号：US12080302B2
公开(公告)日：2024-09-03
申请号：US17768680
申请日：2020-10-15
发明人： Mengqiu Zhang , Erlendur Karlsson
CPC分类号： G10L19/02 , G10L19/26 , G10L21/0232 , H04R3/04 , H04S3/008 , H04S7/303 , H04S2400/01 , H04S2420/01
摘要： A method (1900) for audio signal filtering. The method includes generating (s1902) a pair of filters for a certain location specified by an elevation angle ϑ and an azimuth angle φ, the pair of filters consisting of a right filter (hr(ϑ,φ)) and a left filter (hl(ϑ, φ)); filtering (s1904) an audio signal using the right filter; and filtering (s1906) the audio signal using the left filter. Generating the pair of filters comprises: i) obtaining at least a first set of elevation basis function values at the elevation angle: ii) obtaining at least a first set of azimuth basis function values at the azimuth angle; iii) generating the right filter using: a) at least the first set of elevation basis function values, b) at least the first set of azimuth basis function values, and c) right filter model parameters; and iv) generating the left filter using: a) at least the first set of elevation basis function values, b) at least the first set of azimuth basis function values, and c) left filter model parameters.
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公开(公告)号：US20240271217A1
公开(公告)日：2024-08-15
申请号：US18637814
申请日：2024-04-17
发明人： Lars VILLEMOES , Per EKSTRAND
IPC分类号： C12Q1/6883 , G10L19/02 , G10L19/022 , G10L19/26 , G10L21/038
CPC分类号： C12Q1/6883 , G10L19/0204 , G10L19/022 , G10L19/265 , G10L21/038 , C12Q2600/118 , C12Q2600/156
摘要： The present invention relates to coding of audio signals, and in particular to high frequency reconstruction methods including a frequency domain harmonic transposer. A system and method for generating a high frequency component of a signal from a low frequency component of the signal is described. The system comprises an analysis filter bank (501) comprising an analysis transformation unit (601) having a frequency resolution of Δf; and an analysis window (611) having a duration of DA; the analysis filter bank (501) being configured to provide a set of analysis subband signals from the low frequency component of the signal; a nonlinear processing unit (502, 650) configured to determine a set of synthesis subband signals based on a portion of the set of analysis subband signals, wherein the portion of the set of analysis subband signals is phase shifted by a transposition order T; and a synthesis filter bank (504) comprising a synthesis transformation unit (602) having a frequency resolution of QΔf; and a synthesis window (612) having a duration of DS; the synthesis filter bank (504) being configured to generate the high frequency component of the signal from the set of synthesis subband signals; wherein Q is a frequency resolution factor with Q≥1 and smaller than the transposition order T; and wherein the value of the product of the frequency resolution Δf and the duration DA of the analysis filter bank is selected based on the frequency resolution factor Q.
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公开(公告)号：US12051431B2
公开(公告)日：2024-07-30
申请号：US17105845
申请日：2020-11-27
摘要： An audio similarity evaluator obtains envelope signals for a plurality of frequency ranges on the basis of an input audio signal. The audio similarity evaluator is configured to obtain a modulation information associated with the envelope signals for a plurality of modulation frequency ranges, wherein the modulation information describes the modulation of the envelope signals. The audio similarity evaluator is configured to compare the obtained modulation information with a reference modulation information associated with a reference audio signal, in order to obtain an information about a similarity between the input audio signal and the reference audio signal. An audio encoder uses such an audio similarity evaluator. Another audio similarity evaluator uses a neural net trained using the audio similarity evaluator.
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公开(公告)号：US11996111B2
公开(公告)日：2024-05-28
申请号：US18185691
申请日：2023-03-17
IPC分类号： G10L19/00 , G10L19/02 , G10L19/032 , G10L19/09 , G10L19/12 , G10L19/125 , G10L19/20 , G10L19/22 , G10L19/26 , G10L21/003 , G10L21/007 , G10L21/013 , G10L19/107
CPC分类号： G10L19/26 , G10L19/02 , G10L19/032 , G10L19/09 , G10L19/12 , G10L19/125 , G10L19/20 , G10L19/22 , G10L19/265 , G10L21/003 , G10L21/007 , G10L21/013 , G10L19/0212 , G10L19/107
摘要： In some embodiments, a pitch filter for filtering a preliminary audio signal generated from an audio bitstream is disclosed. The pitch filter has an operating mode selected from one of either: (i) an active mode where the preliminary audio signal is filtered using filtering information to obtain a filtered audio signal, and (ii) an inactive mode where the pitch filter is disabled. The preliminary audio signal is generated in an audio encoder or audio decoder having a coding mode selected from at least two distinct coding modes, and the pitch filter is capable of being selectively operated in either the active mode or the inactive mode while operating in the coding mode based on control information.
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公开(公告)号：US20240135943A1
公开(公告)日：2024-04-25
申请号：US18537655
申请日：2023-12-12
发明人： Emmanuel RAVELLI , Manuel JANDER , Grzegorz PIETRZYK , Martin DIETZ , Marc GAYER
IPC分类号： G10L19/26 , G10L19/005 , G10L19/022 , G10L19/03 , G10L19/12 , G10L19/20
CPC分类号： G10L19/26 , G10L19/005 , G10L19/022 , G10L19/03 , G10L19/12 , G10L19/20 , G10L21/0364
摘要： 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.
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8.发明授权公开(公告)号：US11961528B2
公开(公告)日：2024-04-16
申请号：US18357679
申请日：2023-07-24
CPC分类号： G10L19/02 , G10L19/167 , G10L19/26 , H03M7/6005 , H03M7/6011
摘要： A method for decoding an encoded audio bitstream is disclosed. The method includes receiving the encoded audio bitstream and decoding the audio data to generate a decoded lowband audio signal. The method further includes extracting high frequency reconstruction metadata and filtering the decoded lowband audio signal with an analysis filterbank to generate a filtered lowband audio signal. The method also includes extracting a flag indicating whether either spectral translation or harmonic transposition is to be performed on the audio data and regenerating a highband portion of the audio signal using the filtered lowband audio signal and the high frequency reconstruction metadata in accordance with the flag.
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公开(公告)号：US11935508B2
公开(公告)日：2024-03-19
申请号：US18194414
申请日：2023-03-31
发明人： Per Ekstrand , Lars Villemoes , Per Hedelin
IPC分类号： G10L21/038 , G10H1/00 , G10H1/12 , G10L19/26 , G10L21/0388
CPC分类号： G10H1/0091 , G10H1/125 , G10L19/265 , G10L21/038 , G10H2210/311 , G10L21/0388
摘要： The present document relates to audio coding systems which make use of a harmonic transposition method for high frequency reconstruction (HFR), and to digital effect processors, e.g. so-called exciters, where generation of harmonic distortion adds brightness to the processed signal. In particular, a system configured to generate a high frequency component of a signal from a low frequency component of the signal is described. The system may comprise an analysis filter bank (501) configured to provide a set of analysis subband signals from the low frequency component of the signal; wherein the set of analysis subband signals comprises at least two analysis subband signals; wherein the analysis filter bank (501) has a frequency resolution of Δf. The system further comprises a nonlinear processing unit (502) configured to determine a set of synthesis subband signals from the set of analysis subband signals using a transposition order P; wherein the set of synthesis subband signals comprises a portion of the set of analysis subband signals phase shifted by an amount derived from the transposition order P; and a synthesis filter bank (504) configured to generate the high frequency component of the signal from the set of synthesis subband signals; wherein the synthesis filter bank (504) has a frequency resolution of FΔf; with F being a resolution factor, with F≥1; wherein the transposition order P is different from the resolution factor F.
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公开(公告)号：US11869525B2
公开(公告)日：2024-01-09
申请号：US17592423
申请日：2022-02-03
发明人： Emmanuel Ravelli , Manuel Jander , Grzegorz Pietrzyk , Martin Dietz , Marc Gayer
IPC分类号： G10L19/005 , G10L19/03 , G10L19/12 , H04B1/10 , G10L19/26 , G10L19/022 , G10L19/20 , G10L21/0364 , G11B27/038
CPC分类号： G10L19/26 , G10L19/005 , G10L19/022 , G10L19/03 , G10L19/12 , G10L19/20 , G10L21/0364 , G11B27/038 , H04B1/1027
摘要： 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.
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