Patents by Inventor Per Ekstrand
Per Ekstrand has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20250037688Abstract: 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 ?f.Type: ApplicationFiled: October 10, 2024Publication date: January 30, 2025Applicant: DOLBY INTERNATIONAL ABInventors: Per EKSTRAND, Lars VILLEMOES, Per HEDELIN
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Patent number: 12213004Abstract: 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.Type: GrantFiled: November 6, 2023Date of Patent: January 28, 2025Assignee: DOLBY INTERNATIONAL ABInventors: Heiko Purnhagen, Per Ekstrand
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Patent number: 12211513Abstract: 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.Type: GrantFiled: November 14, 2023Date of Patent: January 28, 2025Assignee: DOLBY INTERNATIONAL ABInventors: Kristofer Kjoerling, Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Publication number: 20250029621Abstract: 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.Type: ApplicationFiled: October 3, 2024Publication date: January 23, 2025Applicant: DOLBY INTERNATIONAL ABInventors: Per EKSTRAND, Lars VILLEMOES
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Patent number: 12205602Abstract: 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.Type: GrantFiled: March 11, 2024Date of Patent: January 21, 2025Assignee: Dolby International ABInventors: Kristofer Kjoerling, Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Publication number: 20250015785Abstract: The present document describes a method (200) for determining N coefficients of an asymmetric prototype filter p0 for use in a low delay M-channel analysis and/or synthesis filter bank (101, 102) comprising M analysis filters hk (103) and/or M synthesis filters fk(106), k=0, . . . , M?1, wherein M is greater than 1, and wherein subband signals which are processed by the analysis and/or synthesis filter bank (101, 102) are decimated by a decimation factor S, with S<M. The method (200) comprises determining (201) a target transfer function of the analysis and/or synthesis filler bank (101, 102) comprising a target delay D; wherein D is smaller or equal to N. Furthermore.Type: ApplicationFiled: November 29, 2022Publication date: January 9, 2025Applicant: DOLBY INTERNATIONAL ABInventor: Per EKSTRAND
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Patent number: 12175993Abstract: 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.Type: GrantFiled: May 29, 2024Date of Patent: December 24, 2024Assignee: DOLBY INTERNATIONAL ABInventors: Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Patent number: 12159642Abstract: 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.Type: GrantFiled: August 21, 2023Date of Patent: December 3, 2024Assignee: DOLBY INTERNATIONAL ABInventor: Per Ekstrand
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Patent number: 12142251Abstract: 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 ?f.Type: GrantFiled: February 12, 2024Date of Patent: November 12, 2024Assignee: DOLBY INTERNATIONAL ABInventors: Per Ekstrand, Lars Villemoes, Per Hedelin
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Patent number: 12136429Abstract: 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.Type: GrantFiled: November 29, 2023Date of Patent: November 5, 2024Assignee: DOLBY INTERNATIONAL ABInventors: Per Ekstrand, Lars Villemoes
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Publication number: 20240355345Abstract: Embodiments relate to an audio processing unit that includes a buffer, bitstream payload deformatter, and a decoding subsystem. The buffer stores at least one block of an encoded audio bitstream. The block includes a fill element that begins with an identifier followed by fill data. The fill data includes at least one flag identifying whether enhanced spectral band replication (eSBR) processing is to be performed on audio content of the block. A corresponding method for decoding an encoded audio bitstream is also provided.Type: ApplicationFiled: April 11, 2024Publication date: October 24, 2024Applicant: DOLBY INTERNATIONAL ABInventors: Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Patent number: 12101613Abstract: A method of audio processing includes generating harmonics in a hybrid complex quadrature mirror filter domain. Generating the harmonics may include multiplication, using a feedback delay loop, and dynamic compression. The harmonics may be generated based on one or more hybrid sub-bands of the complex transform domain signal.Type: GrantFiled: March 19, 2021Date of Patent: September 24, 2024Assignees: Dolby International AB, Dolby Laboratories Licensing CorporationInventors: Per Ekstrand, Yuxing Hao, Xuemei Yu
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Publication number: 20240312471Abstract: 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.Type: ApplicationFiled: May 29, 2024Publication date: September 19, 2024Applicant: DOLBY INTERNATIONAL ABInventors: Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Patent number: 12094477Abstract: Embodiments relate to an audio processing unit that includes a buffer, bitstream payload deformatter, and a decoding subsystem. The buffer stores at least one block of an encoded audio bitstream. The block includes a fill element that begins with an identifier followed by fill data. The fill data includes at least one flag identifying whether enhanced spectral band replication (eSBR) processing is to be performed on audio content of the block. A corresponding method for decoding an encoded audio bitstream is also provided.Type: GrantFiled: May 16, 2023Date of Patent: September 17, 2024Assignee: Dolby International ABInventors: Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Patent number: 12094480Abstract: 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.Type: GrantFiled: July 31, 2023Date of Patent: September 17, 2024Assignee: DOLBY INTERNATIONAL ABInventors: Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Publication number: 20240294987Abstract: 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.Type: ApplicationFiled: April 17, 2024Publication date: September 5, 2024Applicant: Dolby International ABInventors: Lars VILLEMOES, Per EKSTRAND
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Publication number: 20240271217Abstract: 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.Type: ApplicationFiled: April 17, 2024Publication date: August 15, 2024Applicant: Dolby International ABInventors: Lars VILLEMOES, Per EKSTRAND
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Publication number: 20240257790Abstract: 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 ?f.Type: ApplicationFiled: February 12, 2024Publication date: August 1, 2024Applicant: DOLBY INTERNATIONAL ABInventors: Per EKSTRAND, Lars VILLEMOES, Per HEDELIN
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Publication number: 20240212695Abstract: 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.Type: ApplicationFiled: March 11, 2024Publication date: June 27, 2024Applicant: Dolby International ABInventors: Kristofer Kjoerling, Lars Villemoes, Heiko Purnhagen, Per Ekstrand
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Patent number: 11993817Abstract: 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.Type: GrantFiled: January 19, 2023Date of Patent: May 28, 2024Assignee: Dolby International ABInventors: Lars Villemoes, Per Ekstrand