Patents by Inventor Kristofer Kjoerling
Kristofer Kjoerling 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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Patent number: 11145318Abstract: There is provided methods and apparatuses for decoding and encoding of audio signals. In particular, a method for decoding includes receiving a waveform-coded signal having a spectral content corresponding to a subset of the frequency range above a cross-over frequency. The waveform-coded signal is interleaved with a parametric high frequency reconstruction of the audio signal above the cross-over frequency. In this way an improved reconstruction of the high frequency bands of the audio signal is achieved.Type: GrantFiled: October 24, 2018Date of Patent: October 12, 2021Assignee: Dolby International ABInventors: Kristofer Kjoerling, Robin Thesing, Harald Mundt, Heiko Purnhagen, Karl Jonas Roeden
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Patent number: 11133013Abstract: Methods and systems encoding a stereo audio signal having a left channel and a right channel are disclosed. The system includes a downmixer for generating a downmix signal and a residual signal from the stereo audio signal in selected frequency bands representing only part of a used audio frequency range of the stereo audio signal, and a decision module for selecting, in a time variant manner, either left/right perceptual encoding or mid/side perceptual encoding. The system also includes a parameter estimator for estimating stereo parameters for reconstructing a stereo image of a portion of the stereo audio signal, and a perceptual encoder for performing either left/right perceptual encoding or mid/side perceptual encoding based on the selecting to generate an encoded output signal. Finally, the system includes a bitstream generator for creating a bitstream signal comprising the encoded output signal.Type: GrantFiled: August 20, 2019Date of Patent: September 28, 2021Assignee: Dolby International ABInventors: Heiko Purnhagen, Pontus Carlsson, Kristofer Kjoerling
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Patent number: 11114107Abstract: A method for decoding an encoded audio bitstream in an audio processing system is disclosed. The method includes extracting from the encoded audio bitstream a first waveform-coded signal comprising spectral coefficients corresponding to frequencies up to a first cross-over frequency for a time frame and performing parametric decoding at a second cross-over frequency for the time frame to generate a reconstructed signal. The second cross-over frequency is above the first cross-over frequency and the parametric decoding uses reconstruction parameters derived from the encoded audio bitstream to generate the reconstructed signal. The method also includes extracting from the encoded audio bitstream a second waveform-coded signal comprising spectral coefficients corresponding to a subset of frequencies above the first cross-over frequency for the time frame and interleaving the second waveform-coded signal with the reconstructed signal to produce an interleaved signal for the time frame.Type: GrantFiled: October 4, 2019Date of Patent: September 7, 2021Assignee: Dolby International ABInventors: Kristofer Kjoerling, Heiko Purnhagen, Harald Mundt, Karl Jonas Roeden, Leif Sehlstrom
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Publication number: 20210270106Abstract: On the basis of a bitstream (P), an n-channel audio signal (X) is reconstructed by deriving an m-channel core signal (Y) and multichannel coding parameters (a) from the bitstream, where 1?m<n. Also derived from the bitstream are pre-processing dynamic range control, DRC, parameters (DRC2) quantifying an encoder-side dynamic range limiting of the core signal. The n-channel audio signal is obtained by parametric synthesis in accordance with the multichannel coding parameters and while cancelling any encoder-side dynamic range limiting based on the pre-processing DRC parameters. In particular embodiments, the reconstruction further includes use of compensated post-processing DRC parameters quantifying a potential decoder-side dynamic range compression. Cancellation of an encoder-side range limitation and range compression are preferably performed by different decoder-side components. Cancellation and compression may be coordinated by a DRC pre-processor.Type: ApplicationFiled: March 15, 2021Publication date: September 2, 2021Applicants: DOLBY LABORATORIES LICENSING CORPORATION, DOLBY INTERNATIONAL ABInventors: Jeffrey RIEDMILLER, Karl J. ROEDEN, Kristofer KJOERLING, Heiko PURNHAGEN, Vinay MELKOTE, Leif SEHLSTROM
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Patent number: 11037582Abstract: An audio processing system (100) accepts an audio bitstream having one of a plurality of predefined audio frame rates. The system comprises a front-end component (110), which receives a variable number of quantized spectral components, corresponding to one audio frame in any of the predefined audio frame rates, and performs an inverse quantization according to predetermined, frequency-dependent quantization levels. The front-end component may be agnostic of the audio frame rate. The audio processing system further comprises a frequency-domain processing stage (120) and a sample rate converter (130), which provide a reconstructed audio signal sampled at a target sampling frequency independent of the audio frame rate. By its frame-rate adaptability, the system can be configured to operate frame-synchronously in parallel with a video processing system that accepts plural video frame rates.Type: GrantFiled: February 23, 2018Date of Patent: June 15, 2021Assignee: Dolby International ABInventors: Heiko Purnhagen, Kristofer Kjoerling, Alexander Stahlmann, Jens Popp, Karl Jonas Roeden
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Patent number: 11031019Abstract: The application relates to HFR (High Frequency Reconstruction/Regeneration) of audio signals. In particular, the application relates to a method and system for performing HFR of audio signals having large variations in energy level across the low frequency range which is used to reconstruct the high frequencies of the audio signal. A system configured to generate a plurality of high frequency subband signals covering a high frequency interval from a plurality of low frequency subband signals is described.Type: GrantFiled: March 27, 2019Date of Patent: June 8, 2021Assignee: Dolby International ABInventor: Kristofer Kjoerling
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Publication number: 20210158827Abstract: The present document relates to time-alignment of encoded data of an audio encoder with associated metadata, such as spectral band replication (SBR) metadata. An audio decoder configured to determine a reconstructed frame of an audio signal from an access unit of a received data stream is described. The access unit comprises waveform data and metadata, wherein the waveform data and the metadata are associated with the same reconstructed frame of the audio signal. The audio decoder comprises a waveform processing path configured to generate a plurality of waveform subband signals from the waveform data, and a metadata processing path configured to generate decoded metadata from the metadata.Type: ApplicationFiled: October 2, 2020Publication date: May 27, 2021Applicant: DOLBY INTERNATIONAL ABInventors: Kristofer KJOERLING, Heiko PURNHAGEN, Jens POPP
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Patent number: 11017785Abstract: The application relates to audio encoder and decoder systems. An embodiment of the encoder system comprises a downmix stage for generating a downmix signal and a residual signal based on a stereo signal. In addition, the encoder system comprises a parameter determining stage for determining parametric stereo parameters such as an inter-channel intensity difference and an inter-channel cross-correlation. Preferably, the parametric stereo parameters are time- and frequency-variant. Moreover, the encoder system comprises a transform stage. The transform stage generates a pseudo left/right stereo signal by performing a transform based on the downmix signal and the residual signal. The pseudo stereo signal is processed by a perceptual stereo encoder. For stereo encoding, left/right encoding or mid/side encoding is selectable. Preferably, the selection between left/right stereo encoding and mid/side stereo encoding is time- and frequency-variant.Type: GrantFiled: March 29, 2019Date of Patent: May 25, 2021Assignee: Dolby International ABInventors: Heiko Purnhagen, Pontus Carlsson, Kristofer Kjoerling
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Publication number: 20210151062Abstract: 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: ApplicationFiled: April 25, 2019Publication date: May 20, 2021Applicant: Dolby International ABInventors: Kristofer KJOERLING, Lars VILLEMOES, Heiko PURNHAGEN, Per EKSTRAND
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Patent number: 10956121Abstract: In an audio encoder, for audio content received in a source audio format, default gains are generated based on a default dynamic range compression (DRC) curve, and non-default gains are generated for a non-default gain profile. Based on the default gains and non-default gains, differential gains are generated. An audio signal comprising the audio content, the default DRC curve, and differential gains is generated. In an audio decoder, the default DRC curve and the differential gains are identified from the audio signal. Default gains are re-generated based on the default DRC curve. Based on the combination of the re-generated default gains and the differential gains, operations are performed on the audio content extracted from the audio signal.Type: GrantFiled: March 23, 2020Date of Patent: March 23, 2021Assignees: Dolby Laboratories Licensing Corporation, Dolby International ABInventors: Jeroen Koppens, Jeffrey Riedmiller, Kristofer Kjoerling, Alexander Stahlmann, Holger Hoerich, Alan J. Seefeldt
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Publication number: 20210082451Abstract: 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: ApplicationFiled: April 25, 2019Publication date: March 18, 2021Applicant: Dolby International ABInventors: Kristofer KJOERLING, Lars VILLEMOES, Heiko PURNHAGEN, Per EKSTRAND
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Patent number: 10950252Abstract: On the basis of a bitstream (P), an n-channel audio signal (X) is reconstructed by deriving an m-channel core signal (Y) and multichannel coding parameters (a) from the bitstream, where 1?m<n. Also derived from the bitstream are pre-processing dynamic range control, DRC, parameters (DRC2) quantifying an encoder-side dynamic range limiting of the core signal. The n-channel audio signal is obtained by parametric synthesis in accordance with the multichannel coding parameters and while cancelling any encoder-side dynamic range limiting based on the pre-processing DRC parameters. In particular embodiments, the reconstruction further includes use of compensated post-processing DRC parameters quantifying a potential decoder-side dynamic range compression. Cancellation of an encoder-side range limitation and range compression are preferably performed by different decoder-side components. Cancellation and compression may be coordinated by a DRC pre-processor.Type: GrantFiled: December 19, 2019Date of Patent: March 16, 2021Assignees: Dolby Laboratories Licensing Corporation, Dolby International ABInventors: Jeffrey Riedmiller, Karl J. Roeden, Kristofer Kjoerling, Heiko Purnhagen, Vinay Melkote, Leif Sehlstrom
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Publication number: 20210050022Abstract: The present document describes a method (400) for encoding a soundfield representation (SR) input signal (101, 301) describing a soundfield at a reference position, wherein the SR input signal (101, 301) comprises a plurality of channels for a plurality of different directivity patterns of the soundfield at the reference position. The method (400) comprises extracting (401) one or more audio objects (103, 303) from the SR input signal (101, 301). Furthermore, the method (400) comprises determining (402) a residual signal (102, 302) based on the SR input signal (101, 301) and based on the one or more audio objects (103, 303). The method (400) also comprises performing joint coding of the one or more audio objects (103, 303) and/or the residual signal (102, 302). In addition, the method (400) comprises generating (403) a bitstream (701) based on data generated in the context of joint coding of the one or more audio objects (103, 303) and/or the residual signal (102, 302).Type: ApplicationFiled: January 17, 2019Publication date: February 18, 2021Applicants: DOLBY INTERNATIONAL AB, DOLBY LABORATORIES LICENSING CORPORATIONInventors: Kristofer KJOERLING, David S. MCGRATH, Heiko PURNHAGEN, Mark R.P. THOMAS
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Publication number: 20210035592Abstract: 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.Type: ApplicationFiled: October 16, 2020Publication date: February 4, 2021Applicant: DOLBY INTERNATIONAL ABInventors: Barbara RESCH, Kristofer KJÖRLING, Lars VILLEMOES
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Patent number: 10893375Abstract: A method of encoding channel or object based input audio for playback, the method including the steps of: (a) initially rendering the channel or object based input audio into an initial output presentation; (b) determining an estimate of the dominant audio component from the channel or object based input audio and determining a series of dominant audio component weighting factors for mapping the initial output presentation into the dominant audio component; (c) determining an estimate of the dominant audio component direction or position; and (d) encoding the initial output presentation, the dominant audio component weighting factors, the dominant audio component direction or position as the encoded signal for playback.Type: GrantFiled: July 18, 2019Date of Patent: January 12, 2021Assignees: Dolby Laboratories Licensing Corporation, Dolby International ABInventors: Dirk Jeroen Breebaart, David Matthew Cooper, Mark F. Davis, David S. McGrath, Kristofer Kjoerling, Harald Mundt, Rhonda J. Wilson
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Publication number: 20200411019Abstract: 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: January 28, 2019Publication date: December 31, 2020Applicant: DOLBY INTERNATIONAL ABInventors: Kristofer KJOERLING, Lars VILLEMOES, Heiko PURNHAGEN, Per EKSTRAND
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Publication number: 20200388294Abstract: 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: June 23, 2020Publication date: December 10, 2020Applicant: Dolby International ABInventors: Lars G. LILJERYD, Per EKSTRAND, Fredrik HENN, Kristofer KJOERLING
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Publication number: 20200380999Abstract: The present invention proposes a new method for improving the performance of a real-valued filterbank based spectral envelope adjuster. By adaptively locking the gain values for adjacent channels dependent on the sign of the channels, as defined in the application, reduced aliasing is achieved. Furthermore, the grouping of the channels during gain-calculation, gives an improved energy estimate of the real valued subband signals in the filterbank.Type: ApplicationFiled: June 14, 2020Publication date: December 3, 2020Applicant: DOLBY INTERNATIONAL ABInventors: Kristofer KJOERLING, Lars VILLEMOES
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Patent number: 10811023Abstract: The present document relates to time-alignment of encoded data of an audio encoder with associated metadata, such as spectral band replication (SBR) metadata. An audio decoder configured to determine a reconstructed frame of an audio signal from an access unit of a received data stream is described. The access unit comprises waveform data and metadata, wherein the waveform data and the metadata are associated with the same reconstructed frame of the audio signal. The audio decoder comprises a waveform processing path configured to generate a plurality of waveform subband signals from the waveform data, and a metadata processing path configured to generate decoded metadata from the metadata.Type: GrantFiled: September 29, 2017Date of Patent: October 20, 2020Assignee: Dolby International ABInventors: Kristofer Kjoerling, Heiko Purnhagen, Jens Popp
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Patent number: 10811024Abstract: 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.Type: GrantFiled: March 12, 2019Date of Patent: October 20, 2020Assignee: Dolby International ABInventors: Barbara Resch, Kristofer Kjörling, Lars Villemoes