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: 20170206910Abstract: An apparatus and method are disclosed for filtering and performing high frequency reconstruction of an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an arbitrary amount. The high frequency reconstructor modifies at least some of the complex valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by the arbitrary amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter with an arbitrary phase shift.Type: ApplicationFiled: April 4, 2017Publication date: July 20, 2017Applicant: Dolby International ABInventor: Per Ekstrand
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Publication number: 20170194011Abstract: 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.Type: ApplicationFiled: March 15, 2017Publication date: July 6, 2017Inventors: Lars VILLEMOES, Per EKSTRAND, Sascha DISCH, Frederik NAGEL, Stephan WILDE
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Publication number: 20170194942Abstract: An apparatus and method are disclosed for filtering and performing high frequency reconstruction of an audio signal. The apparatus includes an analysis filter bank, a phase shifter, a high frequency reconstructor, and a synthesis filter bank. The analysis filterbank receives real-valued time domain input audio samples and generates complex valued subband samples. The phase shifter shifts a phase of the complex-valued subband samples by an arbitrary amount. The high frequency reconstructor modifies at least some of the complex valued subband samples. A phase shifter unshifts a phase of the modified complex-valued subband samples by the arbitrary amount. The synthesis filter bank receives the modified complex valued subband samples and generates time domain output audio samples. The analysis filter bank comprises analysis filters that are complex exponential modulated versions of a prototype filter with an arbitrary phase shift.Type: ApplicationFiled: March 22, 2017Publication date: July 6, 2017Applicant: Dolby International ABInventor: Per Ekstrand
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Patent number: 9697841Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: GrantFiled: December 6, 2016Date of Patent: July 4, 2017Assignee: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Patent number: 9691400Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: GrantFiled: March 1, 2017Date of Patent: June 27, 2017Assignee: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Patent number: 9691401Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: GrantFiled: March 1, 2017Date of Patent: June 27, 2017Assignee: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Patent number: 9691402Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: GrantFiled: March 1, 2017Date of Patent: June 27, 2017Assignee: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Patent number: 9691399Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: GrantFiled: March 1, 2017Date of Patent: June 27, 2017Assignee: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Patent number: 9691403Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: GrantFiled: March 1, 2017Date of Patent: June 27, 2017Assignee: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Publication number: 20170178644Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: ApplicationFiled: March 1, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Publication number: 20170178647Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.Type: ApplicationFiled: March 8, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Kristofer Kjoerling, Per Ekstrand, Holger Hoerich
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Publication number: 20170178646Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.Type: ApplicationFiled: March 8, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Kristofer Kjoerling, Per Ekstrand, Holger Hoerich
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Publication number: 20170178640Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: ApplicationFiled: March 1, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Publication number: 20170178655Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.Type: ApplicationFiled: March 8, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Kristofer Kjoerling, Per Ekstrand, Holger Hoerich
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Publication number: 20170178643Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: ApplicationFiled: March 1, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Publication number: 20170178654Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.Type: ApplicationFiled: March 8, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Kristofer Kjoerling, Per Ekstrand, Holger Hoerich
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Publication number: 20170178657Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.Type: ApplicationFiled: March 8, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Kristofer Kjoerling, Per Ekstrand, Holger Hoerich
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Publication number: 20170178656Abstract: A method performed in an audio decoder for reconstructing an original audio signal having a lowband portion and a highband portion is disclosed. The method includes receiving an encoded audio signal and extracting reconstruction parameters from the encoded audio signal. The method further includes decoding the encoded audio signal with a core audio decoder to obtain a decoded lowband portion and regenerating the highband portion based at least in part on a cross over frequency and the decoded lowband portion to obtain a regenerated highband portion. The method also includes creating a synthetic sinusoid with a level based at least in part on a spectral envelope value for the particular subband and a noise floor value for the particular subband and adding the synthetic sinusoid to the regenerated highband portion in the particular frequency band specified by the location information.Type: ApplicationFiled: March 8, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Kristofer Kjoerling, Per Ekstrand, Holger Hoerich
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Publication number: 20170178642Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: ApplicationFiled: March 1, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling
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Publication number: 20170178641Abstract: The present invention relates to a new method and apparatus for improvement of High Frequency Reconstruction (HFR) techniques using frequency translation or folding or a combination thereof. The proposed invention is applicable to audio source coding systems, and offers significantly reduced computational complexity. This is accomplished by means of frequency translation or folding in the subband domain, preferably integrated with spectral envelope adjustment in the same domain. The concept of dissonance guard-band filtering is further presented. The proposed invention offers a low-complexity, intermediate quality HFR method useful in speech and natural audio coding applications.Type: ApplicationFiled: March 1, 2017Publication date: June 22, 2017Applicant: Dolby International ABInventors: Lars G. Liljeryd, Per Ekstrand, Fredrik Henn, Kristofer Kjoerling