Patents by Inventor Christian Helmrich

Christian Helmrich 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).

  • Publication number: 20240071395
    Abstract: An apparatus for encoding a first channel and a second channel of an audio input signal including two or more channels to obtain an encoded audio signal according to an embodiment includes a normalizer configured to determine a normalization value for the audio input signal depending on the first channel of the audio input signal and depending on the second channel of the audio input signal. Moreover, the apparatus includes an encoding unit configured to generate a processed audio signal having a first channel and a second channel. The encoding unit is configured to encode the processed audio signal to obtain the encoded audio signal.
    Type: Application
    Filed: October 30, 2023
    Publication date: February 29, 2024
    Inventors: Emmanuel RAVELLI, Markus SCHNELL, Stefan DOEHLA, Wolfgang JAEGERS, Martin DIETZ, Christian HELMRICH, Goran MARKOVIC, Eleni FOTOPOULOU, Markus MULTRUS, Stefan BAYER, Guillaume FUCHS, Juergen HERRE
  • Patent number: 11908485
    Abstract: An apparatus for selecting one of a first encoding algorithm having a first characteristic and a second encoding algorithm having a second characteristic for encoding a portion of an audio signal to obtain an encoded version of the portion of the audio signal has a first estimator for estimating a first quality measure for the portion of the audio signal, which is associated with the first encoding algorithm, without actually encoding and decoding the portion of the audio signal using the first encoding algorithm. A second estimator is provided for estimating a second quality measure for the portion of the audio signal, which is associated with the second encoding algorithm, without actually encoding and decoding the portion of the audio signal using the second encoding algorithm. The apparatus has a controller for selecting the first or second encoding algorithms based on a comparison between the first and second quality measures.
    Type: Grant
    Filed: November 23, 2022
    Date of Patent: February 20, 2024
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Emmanuel Ravelli, Stefan Doehla, Guillaume Fuchs, Eleni Fotopoulou, Christian Helmrich
  • Publication number: 20240048719
    Abstract: Apparatus for encoding a video having a sequence of frames using rate control, configured to determine a global quantization parameter for the sequence of frames based on a target bit-rate, and to perform a coding pass, coding the sequence of frames, using the global quantization parameter by determining a frame quantization parameter per frame of the sequence of frames on the basis of the global quantization parameter, and subjecting the sequence of frames to R/D optimizing encoding by using, for each frame, the frame quantization parameter determined for the respective frame so as to obtain an encoded version of an associated coding size for the respective frame.
    Type: Application
    Filed: October 13, 2023
    Publication date: February 8, 2024
    Inventors: Christian Helmrich, Ivan Zupancic, Benjamin Bross, Adam Wieckowski, Jonathan Pfaff, Jens Brandenburg, Heiko Schwarz, Detlev Marpe
  • Patent number: 11887611
    Abstract: In multichannel audio coding, an improved coding efficiency is achieved by the following measure: the noise filling of zero-quantized scale factor bands is performed using noise filling sources other than artificially generated noise or spectral replica. In particular, the coding efficiency in multichannel audio coding may be rendered more efficient by performing the noise filling based on noise generated using spectral lines from a previous frame of, or a different channel of the current frame of, the multichannel audio signal.
    Type: Grant
    Filed: December 27, 2022
    Date of Patent: January 30, 2024
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Maria Luis Valero, Christian Helmrich, Johannes Hilpert
  • Publication number: 20240029744
    Abstract: An audio decoder for providing at least four audio channel signals on the basis of an encoded representation is configured to provide a first residual signal and a second residual signal on the basis of a jointly encoded representation of the first residual signal and of the second residual signal using a multi-channel decoding. The audio decoder is configured to provide a first audio channel signal and a second audio channel signal on the basis of a first downmix signal and the first residual signal using a residual-signal-assisted multi-channel decoding. The audio decoder is configured to provide a third audio channel signal and a fourth audio channel signal on the basis of a second downmix signal and the second residual signal using a residual-signal-assisted multi-channel decoding. An audio encoder is based on corresponding considerations.
    Type: Application
    Filed: May 22, 2023
    Publication date: January 25, 2024
    Applicant: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Sascha Dick, Christian Ertel, Christian Helmrich, Johannes Hilpert, Andreas Hoelzer, Achim Kuntz
  • Patent number: 11869514
    Abstract: An apparatus for decoding an audio signal includes a receiving interface, wherein the receiving interface is configured to receive a first frame and a second frame. Moreover, the apparatus includes a noise level tracing unit for determining noise level information being represented in a tracing domain. Furthermore, the apparatus includes a first reconstruction unit for reconstructing a third audio signal portion of the audio signal depending on the noise level information and a second reconstruction unit for reconstructing a fourth audio signal portion depending on noise level information being represented in the second reconstruction domain.
    Type: Grant
    Filed: April 15, 2020
    Date of Patent: January 9, 2024
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Michael Schnabel, Goran Markovic, Ralph Sperschneider, Jérémie Lecomte, Christian Helmrich
  • Patent number: 11862182
    Abstract: A frequency-domain audio codec is provided with the ability to additionally support a certain transform length in a backward-compatible manner, by the following: the frequency-domain coefficients of a respective frame are transmitted in an interleaved manner irrespective of the signalization signaling for the frames as to which transform length actually applies, and additionally the frequency-domain coefficient extraction and the scale factor extraction operate independent from the signalization. By this measure, old-fashioned frequency-domain audio coders/decoders, insensitive for the signalization, would be able to nevertheless operate without faults and with reproducing a reasonable quality. Concurrently, frequency-domain audio coders/decoders able to support the additional transform length would offer even better quality despite the backward compatibility.
    Type: Grant
    Filed: April 9, 2021
    Date of Patent: January 2, 2024
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Sascha Dick, Christian Helmrich, Andreas Hoelzer
  • Patent number: 11854559
    Abstract: A schematic block diagram of a decoder for decoding an encoded audio signal is shown. The decoder includes an adaptive spectrum-time converter and an overlap-add-processor. The adaptive spectrum-time converter converts successive blocks of spectral values into successive blocks of time values, e.g. via a frequency-to-time transform. Furthermore, the adaptive spectrum-time converter receives a control information and switches, in response to the control information, between transform kernels of a first group of transform kernels including one or more transform kernels having different symmetries at sides of a kernel, and a second group of transform kernels including one or more transform kernels having the same symmetries at sides of a transform kernel. Moreover, the overlap-add-processor overlaps and adds the successive blocks of time values to obtain decoded audio values, which may be a decoded audio signal.
    Type: Grant
    Filed: April 15, 2022
    Date of Patent: December 26, 2023
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Christian Helmrich, Bernd Edler
  • Patent number: 11854561
    Abstract: The invention provides an audio encoder including a combination of a linear predictive coding filter having a plurality of linear predictive coding coefficients and a time-frequency converter, wherein the combination is configured to filter and to convert a frame of the audio signal into a frequency domain in order to output a spectrum based on the frame and on the linear predictive coding coefficients; a low frequency emphasizer configured to calculate a processed spectrum based on the spectrum, wherein spectral lines of the processed spectrum representing a lower frequency than a reference spectral line are emphasized; and a control device configured to control the calculation of the processed spectrum by the low frequency emphasizer depending on the linear predictive coding coefficients of the linear predictive coding filter.
    Type: Grant
    Filed: November 22, 2022
    Date of Patent: December 26, 2023
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Stefan Doehla, Bernhard Grill, Christian Helmrich, Nikolaus Rettelbach
  • Patent number: 11842742
    Abstract: An apparatus for encoding a first channel and a second channel of an audio input signal including two or more channels to obtain an encoded audio signal according to an embodiment includes a normalizer configured to determine a normalization value for the audio input signal depending on the first channel of the audio input signal and depending on the second channel of the audio input signal. Moreover, the apparatus includes an encoding unit configured to generate a processed audio signal having a first channel and a second channel. The encoding unit is configured to encode the processed audio signal to obtain the encoded audio signal.
    Type: Grant
    Filed: July 20, 2018
    Date of Patent: December 12, 2023
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung V.
    Inventors: Emmanuel Ravelli, Markus Schnell, Stefan Doehla, Wolfgang Jaegers, Martin Dietz, Christian Helmrich, Goran Markovic, Eleni Fotopoulou, Markus Multrus, Stefan Bayer, Guillaume Fuchs, Juergen Herre
  • Patent number: 11843805
    Abstract: Provided are an encoder, a decoder and methods for applying and varying a strength of a deblocking or deringing filter for filtering a block of a picture, wherein the deblocking filter is configured to determine, for each of at least eight border portions of a border of the block, a dissimilarity between an unfiltered content of the block and a surrounding picture content around the block along the respective border portion, the eight border portions including four corner border portions, each arranged at a corner of the block, and four edge border portions, each arranged at intermediary portions of the border between the corners of the block. Furthermore, the deblocking filter is configured to parametrize a deblocking filtering of the block using the dissimilarities determined for the at least eight border portions in order to obtain a filtered content of the block.
    Type: Grant
    Filed: March 25, 2021
    Date of Patent: December 12, 2023
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventor: Christian Helmrich
  • Publication number: 20230377586
    Abstract: An apparatus for decoding an encoded multichannel signal of a current frame to obtain three or more current audio output channels is provided. A multichannel processor is adapted to select two decoded channels from three or more decoded channels depending on first multichannel parameters. Moreover, the multichannel processor is adapted to generate a first group of two or more processed channels based on the selected channels. A noise filling module is adapted to identify for at least one of the selected channels, one or more frequency bands, within which all spectral lines are quantized to zero, and to generate a mixing channel using, depending on side information, a proper subset of three or more previous audio output channels that have been decoded, and to fill the spectral lines of frequency bands, within which all spectral lines are quantized to zero, with noise generated using spectral lines of the mixing channel.
    Type: Application
    Filed: July 11, 2023
    Publication date: November 23, 2023
    Inventors: Sascha DICK, Christian HELMRICH, Nikolaus RETTELBACH, Florian SCHUH, Richard FUEG, Frederik NAGEL
  • Publication number: 20230352032
    Abstract: An apparatus for generating a decoded two-channel signal, comprising: a parametric decoder for providing parametric data for a second set of second spectral portions and a two-channel identification identifying for a second spectral portion of the second set of second spectral portions either a first two-channel representation for the second spectral portion of the second set of second spectral portions or a second two-channel representation for the second spectral portion of the second set of second spectral portions, the second two-channel representation being different from the first two-channel representation; and a frequency regenerator for regenerating the second spectral portion of the second set of second spectral portions depending on a first spectral portion of a first set of first spectral portions, the parametric data for the second spectral portion of the second set of second spectral portions and the two-channel identification for the second spectral portion of the second set of second spectral
    Type: Application
    Filed: July 11, 2023
    Publication date: November 2, 2023
    Inventors: Sascha DISCH, Frederik NAGEL, Ralf GEIGER, Balaji Nagendran THOSHKAHNA, Konstantin SCHMIDT, Stefan BAYER, Christian NEUKAM, Bernd EDLER, Christian HELMRICH
  • Publication number: 20230328242
    Abstract: A picture in a data stream is subdivided into different size transform bocks. For a transform block, a transformation is selected by checking whether the block's size exceeds a threshold. If it does, a default technique is used to select the transformation. If it does not, a transformation is used from a list of transformations as identified by an index, the list including an identity transformation and non-identity transformations. A coefficients block in the data stream is decoded, and if the selected transformation is the identity transformation, then the coefficients block is used as a residual sample array, and if the selected transformation is not the identity transformation, the coefficients block is subjected to an inverse transformation corresponding to the selected transformation to obtain a residual sample array used to correct a prediction for the transform block.
    Type: Application
    Filed: June 13, 2023
    Publication date: October 12, 2023
    Inventors: Benjamin BROSS, Phan Hoang Tung NGUYEN, Paul KEYDEL, Heiko SCHWARZ, Detlev MARPE, Thomas WIEGAND, Christian HELMRICH
  • Publication number: 20230319301
    Abstract: An encoder/decoder is based on a combination of two audio or video channels to obtain a first combination signal as a mid-signal and a residual signal derivable using a predicted side signal derived from the mid-signal. A decoder uses the prediction residual signal, the first combination signal, a prediction direction indicator and prediction information to derive decoded first channel and second channel signals. A real-to-imaginary transform can be applied for estimating the imaginary part of the spectrum of the first combination signal. The prediction signal used in the derivation of the prediction residual signal, the real-valued first combination signal is multiplied by a real portion of the complex prediction information and the estimated imaginary part of the first combination signal is multiplied by an imaginary portion of the complex prediction information.
    Type: Application
    Filed: April 25, 2023
    Publication date: October 5, 2023
    Inventors: Julien ROBILLIARD, Matthias NEUSINGER, Christian HELMRICH, Johannes HILPERT, Nikolaus RETTELBACH, Sascha DISCH, Bernd EDLER
  • Patent number: 11776551
    Abstract: An apparatus for decoding an audio signal is provided, having a receiving interface, configured to receive a first frame having a first audio signal portion of the audio signal, and configured to receive a second frame having a second audio signal portion of the audio signal; a noise level tracing unit, wherein the noise level tracing unit is configured to determine noise level information depending on at least one of the first audio signal portion and the second audio signal portion; a first reconstruction unit for reconstructing, in a first reconstruction domain, a third audio signal portion of the audio signal depending on the noise level information; a transform unit for transforming the noise level information to a second reconstruction domain; and a second reconstruction unit for reconstructing, in the second reconstruction domain, a fourth audio signal portion of the audio signal depending on the noise level information.
    Type: Grant
    Filed: December 14, 2020
    Date of Patent: October 3, 2023
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Michael Schnabel, Markovic Goran, Ralph Sperschneider, Jérémie Lecomte, Christian Helmrich
  • Patent number: 11769513
    Abstract: An apparatus for decoding an encoded audio signal having an encoded representation of a first set of first spectral portions and an encoded representation of parametric data indicating spectral energies for a second set of second spectral portions, has: an audio decoder for decoding the encoded representation of the first set of the first spectral portions to obtain a first set of first spectral portions and for decoding the encoded representation of the parametric data to obtain a decoded parametric data for the second set of second spectral portions indicating, for individual reconstruction bands, individual energies; a frequency regenerator for reconstructing spectral values in a reconstruction band having a second spectral portion using a first spectral portion of the first set of the first spectral portions and an individual energy for the reconstruction band, the reconstruction band having a first spectral portion and the second spectral portion.
    Type: Grant
    Filed: January 25, 2022
    Date of Patent: September 26, 2023
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Andreas Niedermeier, Christian Ertel, Ralf Geiger, Florin Ghido, Christian Helmrich
  • Publication number: 20230282221
    Abstract: An apparatus for generating an encoded signal includes: a window sequence controller for generating a window sequence information for windowing an audio or image signal, the window sequence information indicating a first window for generating a first frame of spectral values, a second window function and at least one third window function for generating a second frame of spectral values, wherein the first window function, the second window function and the one or more third window functions overlap within a multi-overlap region; a preprocessor for windowing a second block of samples corresponding to the second window function and the at least one third window functions using an auxiliary window function to acquire a second block of windowed samples, a spectrum converter for applying an aliasing-introducing transform; and a processor for processing the first frame and the second frame to acquire encoded frames of the audio or image signal.
    Type: Application
    Filed: February 17, 2023
    Publication date: September 7, 2023
    Inventors: Christian HELMRICH, Jérémie LECOMTE, Goran MARKOVIC, Markus SCHNELL, Bernd EDLER, Stefan REUSCHL
  • Publication number: 20230282223
    Abstract: An apparatus for processing an audio signal having associated therewith a pitch lag information and a gain information, includes a domain converter for converting a first domain representation of the audio signal into a second domain representation of the audio signal; and a harmonic post-filter for filtering the second domain representation of the audio signal, wherein the post-filter is based on a transfer function including a numerator and a denominator, wherein the numerator includes a gain value indicated by the gain information, and wherein the denominator includes an integer part of a pitch lag indicated by the pitch lag information and a multi-tap filter depending on a fractional part of the pitch lag.
    Type: Application
    Filed: May 16, 2023
    Publication date: September 7, 2023
    Inventors: Emmanuel RAVELLI, Christian HELMRICH, Goran MARKOVIC, Matthias NEUSINGER, Sascha DISCH, Manuel JANDER, Martin DIETZ
  • Patent number: RE49717
    Abstract: An encoder/decoder is based on a combination of two audio or video channels to obtain a first combination signal as a mid-signal and a residual signal derivable using a predicted side signal derived from the mid-signal. A decoder uses the prediction residual signal, the first combination signal, a prediction direction indicator and prediction information to derive decoded first channel and second channel signals. A real-to-imaginary transform can be applied for estimating the imaginary part of the spectrum of the first combination signal. The prediction signal used in the derivation of the prediction residual signal, the real-valued first combination signal is multiplied by a real portion of the complex prediction information and the estimated imaginary part of the first combination signal is multiplied by an imaginary portion of the complex prediction information.
    Type: Grant
    Filed: November 17, 2020
    Date of Patent: October 24, 2023
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Julien Robilliard, Matthias Neusinger, Christian Helmrich, Johannes Hilpert, Nikolaus Rettelbach, Sascha Disch, Bernd Edler