公开(公告)号：US20240155427A1

公开(公告)日：2024-05-09

申请号：US18503083

申请日：2023-11-06

Applicant: Dolby International AB

Inventor： Heiko PURNHAGEN ,  Per EKSTRAND

IPC: H04W28/06 ,  G10L19/008 ,  G10L19/035 ,  H04S1/00 ,  H04W28/02

CPC classification number: H04W28/065 ,  G10L19/008 ,  G10L19/035 ,  H04S1/007 ,  H04W28/0215 ,  G10L19/038 ,  H04S2420/03

Abstract: The present disclosure provides methods, devices and computer program products for non-uniform quantization of parameters. The disclosure further relates to a method and apparatus for reconstructing an audio object in an audio decoding system taking the non-uniformly quantized parameters into account. According to the disclosure, such an approach renders it possible to reduce bit consumption without substantially reducing the quality of the reconstructed audio object.

公开(公告)号：US20240135939A1

公开(公告)日：2024-04-25

申请号：US18397158

申请日：2023-12-27

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: G10L19/008 ,  G10L19/02 ,  G10L21/038 ,  G10L21/04

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：US20230245637A1

公开(公告)日：2023-08-03

申请号：US18194414

申请日：2023-03-31

Applicant: DOLBY INTERNATIONAL AB

Inventor： Per EKSTRAND ,  Lars VILLEMOES ,  Per HEDELIN

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

CPC classification number: G10H1/0091 ,  G10L21/038 ,  G10L19/265 ,  G10H1/125 ,  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：US20230197103A1

公开(公告)日：2023-06-22

申请号：US18113406

申请日：2023-02-23

Applicant: Dolby International AB

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

IPC: G10L21/0388 ,  G10L19/008 ,  G10L19/02 ,  H04S3/00

CPC classification number: G10L21/0388 ,  G10L19/02 ,  G10L19/008 ,  H04S3/008

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：US20230162748A1

公开(公告)日：2023-05-25

申请号：US18157644

申请日：2023-01-20

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：US20230087552A1

公开(公告)日：2023-03-23

申请号：US17987545

申请日：2022-11-15

Applicant: Dolby International AB

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

IPC: G10L21/0388 ,  G10L19/008 ,  G10L19/02 ,  H04S3/00

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：US20230027660A1

公开(公告)日：2023-01-26

申请号：US17954179

申请日：2022-09-27

Applicant: DOLBY INTERNATIONAL AB

Inventor： Per EKSTRAND ,  Lars VILLEMOES

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

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：US20210151062A1

公开(公告)日：2021-05-20

申请号：US17050664

申请日：2019-04-25

Applicant: Dolby International AB

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

IPC: 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：US20200294516A1

公开(公告)日：2020-09-17

申请号：US16827541

申请日：2020-03-23

Applicant: Dolby International AB

Inventor： Per EKSTRAND ,  Lars VILLEMOES

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

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：US20190320348A1

公开(公告)日：2019-10-17

申请号：US16454649

申请日：2019-06-27

Applicant: DOLBY INTERNATIONAL AB

Inventor： Heiko PURNHAGEN ,  Per EKSTRAND

IPC: H04W28/06 ,  G10L19/008 ,  H04W28/02 ,  G10L19/035 ,  H04S1/00

Abstract: The present disclosure provides methods, devices and computer program products for non-uniform quantization of parameters. The disclosure further relates to a method and apparatus for reconstructing an audio object in an audio decoding system taking the non-uniformly quantized parameters into account. According to the disclosure, such an approach renders it possible to reduce bit consumption without substantially reducing the quality of the reconstructed audio object.