公开(公告)号：US20200349911A1

公开(公告)日：2020-11-05

申请号：US16876793

申请日：2020-05-18

Applicant: Dolby International AB

Inventor： Per EKSTRAND ,  Lars VILLEMOES ,  Per HEDELIN

IPC: G10H1/00 ,  G10L21/038 ,  G10L19/26 ,  G10H1/12

Abstract: 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.

公开(公告)号：US20200066292A1

公开(公告)日：2020-02-27

申请号：US16666237

申请日：2019-10-28

Applicant: Dolby International AB

Inventor： Per EKSTRAND

IPC: G10L21/00 ,  H03H17/02 ,  H04S7/00 ,  G10L19/26 ,  G10L19/02 ,  G10L19/008 ,  G06F17/11 ,  H04R3/04 ,  G06F17/10

Abstract: An apparatus and method are disclosed for processing an audio signal. The apparatus includes an input interface, a digital filterbank having an analysis part and a synthesis part, a first phase shifter, a spectral envelope adjuster, a second phase shifter, and an output interface. The first phase shifter and the second phase shifter reduce a complexity of the digital filterbank, which includes both analysis and synthesis filters that are complex-exponential modulated versions of a prototype filter.

公开(公告)号：US20170194011A1

公开(公告)日：2017-07-06

申请号：US15459520

申请日：2017-03-15

Applicant: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V. ,  Dolby International AB

Inventor： Lars VILLEMOES ,  Per EKSTRAND ,  Sascha DISCH ,  Frederik NAGEL ,  Stephan WILDE

IPC: G10L19/02 ,  G10L19/008

CPC classification number: G10L19/008 ,  G10L19/0204 ,  G10L21/038 ,  G10L21/04

Abstract: An apparatus for processing an input audio signal relies on a cascade of filterbanks, the cascade having a synthesis filterbank for synthesizing an audio intermediate signal from the input audio signal, the input audio signal being represented by a plurality of first subband signals generated by an analysis filterbank, wherein a number of filterbank channels of the synthesis filterbank is smaller than a number of channels of the analysis filterbank. The apparatus furthermore has a further analysis filterbank for generating a plurality of second subband signals from the audio intermediate signal, wherein the further analysis filterbank has a number of channels being different from the number of channels of the synthesis filterbank, so that a sampling rate of a subband signal of the plurality of second subband signals is different from a sampling rate of a first subband signal of the plurality of first subband signals.

公开(公告)号：US20160358616A1

公开(公告)日：2016-12-08

申请号：US15240727

申请日：2016-08-18

Applicant: DOLBY INTERNATIONAL AB

Inventor： Kristofer KJOERLING ,  Per EKSTRAND ,  Holger HOERICH

IPC: G10L19/07 ,  G10L19/02 ,  G10L19/26

CPC classification number: G10L19/0208 ,  G10L19/0017 ,  G10L19/0204 ,  G10L19/028 ,  G10L19/06 ,  G10L19/07 ,  G10L19/093 ,  G10L19/167 ,  G10L19/24 ,  G10L19/26 ,  G10L19/265 ,  G10L21/038

Abstract: The present invention proposes a new method and a new apparatus for enhancement of audio source coding systems utilising high frequency reconstruction (HFR). It utilises a detection mechanism on the encoder side to assess what parts of the spectrum will not be correctly reproduced by the HFR method in the decoder. Information on this is efficiently coded and sent to the decoder, where it is combined with the output of the HFR unit.

Abstract translation: 本发明提出了一种利用高频重构（HFR）来增强音频源编码系统的新方法和新装置。 它利用编码器侧的检测机制来评估解码器中HFR方法将不能正确地再现频谱的哪些部分。 关于此的信息被有效地编码并发送到解码器，其中它与HFR单元的输出组合。

公开(公告)号：US20130226597A1

公开(公告)日：2013-08-29

申请号：US13865450

申请日：2013-04-18

Applicant: DOLBY INTERNATIONAL AB

Inventor： Kristofer KJOERLING ,  Per EKSTRAND ,  Holger HOERICH

IPC: G10L19/00

CPC classification number: G10L19/0208 ,  G10L19/0017 ,  G10L19/0204 ,  G10L19/028 ,  G10L19/06 ,  G10L19/07 ,  G10L19/093 ,  G10L19/167 ,  G10L19/24 ,  G10L19/26 ,  G10L19/265 ,  G10L21/038

Abstract: The present invention proposes a new method and a new apparatus for enhancement of audio source coding systems utilising high frequency reconstruction (HFR). It utilises a detection mechanism on the encoder side to assess what parts of the spectrum will not be correctly reproduced by the HFR method in the decoder. Information on this is efficiently coded and sent to the decoder, where it is combined with the output of the HFR unit.

公开(公告)号：US20250054505A1

公开(公告)日：2025-02-13

申请号：US18905705

申请日：2024-10-03

Applicant: DOLBY INTERNATIONAL AB

Inventor： Per EKSTRAND ,  Lars VILLEMOES

IPC: G10L19/022 ,  G10L19/02 ,  G10L19/24 ,  G10L21/038 ,  G10L21/04

Abstract: The present invention relates to transposing signals in time and/or frequency and in particular to coding of audio signals. More particular, the present invention relates to high frequency reconstruction (HFR) methods including a frequency domain harmonic transposer. A method and system for generating a transposed output signal from an input signal using a transposition factor T is described. The system comprises an analysis window of length La, extracting a frame of the input signal, and an analysis transformation unit of order M transforming the samples into M complex coefficients. M is a function of the transposition factor T. The system further comprises a nonlinear processing unit altering the phase of the complex coefficients by using the transposition factor T, a synthesis transformation unit of order M transforming the altered coefficients into M altered samples, and a synthesis window of length Ls, generating a frame of the output signal.

公开(公告)号：US20250037688A1

公开(公告)日：2025-01-30

申请号：US18912309

申请日：2024-10-10

Applicant: DOLBY INTERNATIONAL AB

Inventor： Per EKSTRAND ,  Lars VILLEMOES ,  Per HEDELIN

IPC: G10H1/00 ,  G10H1/12 ,  G10L19/26 ,  G10L21/038 ,  G10L21/0388

Abstract: 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.

公开(公告)号：US20240257790A1

公开(公告)日：2024-08-01

申请号：US18439478

申请日：2024-02-12

Applicant: DOLBY INTERNATIONAL AB

Inventor： Per EKSTRAND ,  Lars VILLEMOES ,  Per HEDELIN

IPC: G10H1/00 ,  G10H1/12 ,  G10L19/26 ,  G10L21/038 ,  G10L21/0388

CPC classification number: G10H1/0091 ,  G10H1/125 ,  G10L19/265 ,  G10L21/038 ,  G10H2210/311 ,  G10L21/0388

Abstract: 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.

公开(公告)号：US20240161763A1

公开(公告)日：2024-05-16

申请号：US18417902

申请日：2024-01-19

Applicant: DOLBY INTERNATIONAL AB

Inventor： Kristofer KJOERLING ,  Lars VILLEMOES ,  Heiko PURNHAGEN ,  Per EKSTRAND

IPC: G10L19/18 ,  G10L21/038

CPC classification number: G10L19/18 ,  G10L21/038

Abstract: 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. The high frequency regeneration is performed as a post-processing operation with a delay of 3010 samples per audio channel.

公开(公告)号：US20240055010A1

公开(公告)日：2024-02-15

申请号：US18452697

申请日：2023-08-21

Applicant: DOLBY INTERNATIONAL AB

Inventor： Per EKSTRAND

IPC: G10L21/00 ,  G06F17/10 ,  H03H17/02 ,  G10L19/02 ,  G10L19/26 ,  H04R3/04 ,  G06F17/11 ,  G10L19/008 ,  H04S7/00

CPC classification number: G10L21/00 ,  G06F17/10 ,  H03H17/0266 ,  H03H17/0248 ,  G10L19/0204 ,  G10L19/26 ,  H04R3/04 ,  G06F17/11 ,  H03H17/0201 ,  G10L19/008 ,  G10L19/0208 ,  G10L19/265 ,  H03H17/0275 ,  H04S7/307 ,  H03H17/0294 ,  H03H2017/0297

Abstract: An apparatus and method are disclosed for processing an audio signal. The apparatus includes an input interface, a digital filterbank having an analysis part and a synthesis part, a first phase shifter, a spectral envelope adjuster, a second phase shifter, and an output interface. The first phase shifter and the second phase shifter reduce a complexity of the digital filterbank, which includes both analysis and synthesis filters that are complex-exponential modulated versions of a prototype filter.