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).

  • Patent number: 11031022
    Abstract: Noise filling of a spectrum of an audio signal is improved in quality with respect to the noise filled spectrum so that the reproduction of the noise filled audio signal is less annoying, by performing the noise filling in a manner dependent on a tonality of the audio signal.
    Type: Grant
    Filed: July 26, 2019
    Date of Patent: June 8, 2021
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Sascha Disch, Marc Gayer, Christian Helmrich, Goran Markovic, Maria Luis Valero
  • Publication number: 20210142809
    Abstract: An apparatus for decoding an encoded audio signal to obtain a reconstructed audio signal is provided. The apparatus includes a receiving interface, a delay buffer and a sample processor for processing the selected audio signal samples to obtain reconstructed audio signal samples of the reconstructed audio signal. The sample selector is configured to select, if a current frame is received by the receiving interface and if the current frame being received by the receiving interface is not corrupted, the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer depending on a pitch lag information being included by the current frame.
    Type: Application
    Filed: November 20, 2020
    Publication date: May 13, 2021
    Inventors: Michael SCHNABEL, Goran MARKOVIC, Ralph SPERSCHNEIDER, Jérémie LECOMTE, Christian HELMRICH
  • Publication number: 20210125624
    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: January 8, 2021
    Publication date: April 29, 2021
    Inventors: Emmanuel RAVELLI, Christian HELMRICH, Goran MARKOVIC, Matthias NEUSINGER, Sascha DISCH, Manuel JANDER, Martin DIETZ
  • Patent number: 10984810
    Abstract: An audio decoder provides a decoded audio information on the basis of an encoded audio information including linear prediction coefficients (LPC) and includes a tilt adjuster to adjust a tilt of a noise using linear prediction coefficients of a current frame to acquire a tilt information and a noise inserter configured to add the noise to the current frame in dependence on the tilt information. Another audio decoder includes a noise level estimator to estimate a noise level for a current frame using a linear prediction coefficient of at least one previous frame to acquire a noise level information; and a noise inserter to add a noise to the current frame in dependence on the noise level information provided by the noise level estimator. Thus, side information about a background noise in the bit-stream may be omitted. Methods and computer programs serve a similar purpose.
    Type: Grant
    Filed: February 26, 2019
    Date of Patent: April 20, 2021
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Guillaume Fuchs, Christian Helmrich, Manuel Jander, Benjamin Schubert, Yoshikazu Yokotani
  • Patent number: 10984809
    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: February 25, 2019
    Date of Patent: April 20, 2021
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Sascha Dick, Christian Helmrich, Andreas Hoelzer
  • Patent number: 10978084
    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: October 7, 2019
    Date of Patent: April 13, 2021
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Maria Luis Valero, Christian Helmrich, Johannes Hilpert
  • Publication number: 20210098003
    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: Application
    Filed: December 14, 2020
    Publication date: April 1, 2021
    Inventors: Michael SCHNABEL, Markovic GORAN, Ralph SPERSCHNEIDER, Jérémie LECOMTE, Christian HELMRICH
  • Publication number: 20210074307
    Abstract: An audio decoder provides a decoded audio information on the basis of an encoded audio information including linear prediction coefficients (LPC) and includes a tilt adjuster to adjust a tilt of a noise using linear prediction coefficients of a current frame to acquire a tilt information and a noise inserter configured to add the noise to the current frame in dependence on the tilt information. Another audio decoder includes a noise level estimator to estimate a noise level for a current frame using a linear prediction coefficient of at least one previous frame to acquire a noise level information; and a noise inserter to add a noise to the current frame in dependence on the noise level information provided by the noise level estimator. Thus, side information about a background noise in the bit-stream may be omitted. Methods and computer programs serve a similar purpose.
    Type: Application
    Filed: November 24, 2020
    Publication date: March 11, 2021
    Inventors: Guillaume FUCHS, Christian HELMRICH, Manuel JANDER, Benjamin SCHUBERT, Yoshikazu YOKOTANI
  • Publication number: 20210065723
    Abstract: An apparatus for generating a decoded two-channel signal includes: an audio processor for decoding an encoded two-channel signal to obtain a first set of first spectral portions; a parametric decoder for providing parametric data for a second set of second spectral portions and a two-channel identification identifying either a first or a second different two-channel representation for the second spectral portions; and a frequency regenerator for regenerating a second spectral portion depending on a first spectral portion of the first set of first spectral portions, the parametric data for the second portion and the two-channel identification for the second portion.
    Type: Application
    Filed: November 10, 2020
    Publication date: March 4, 2021
    Inventors: Sascha DISCH, Frederik NAGEL, Ralf GEIGER, Balaji Nagendran THOSHKAHNA, Konstantin SCHMIDT, Stefan BAYER, Christian NEUKAM, Bernd EDLER, Christian HELMRICH
  • Publication number: 20210065725
    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: August 17, 2020
    Publication date: March 4, 2021
    Inventors: Christian HELMRICH, Jérémie LECOMTE, Goran MARKOVIC, Markus SCHNELL, Bernd EDLER, Stefan REUSCHL
  • Publication number: 20210056979
    Abstract: An audio decoder for providing at least four bandwidth-extended channel signals on the basis of an encoded representation provides first and second downmix signals on the basis of a jointly encoded representation of the first and second downmix signals using a multi-channel decoding and provides at least first and second audio channel signals on the basis of the first downmix signal using a multi-channel decoding, and provides at least third and fourth audio channel signals on the basis of the second downmix signal using a multi-channel decoding. It performs a multi-channel bandwidth extension on the basis of the first and third audio channel signals, to obtain first and third bandwidth-extended channel signals, and performs a multi-channel bandwidth extension on the basis of the second and fourth audio channel signals, to obtain second and fourth bandwidth extended channel signals. An audio encoder uses a related concept.
    Type: Application
    Filed: September 3, 2020
    Publication date: February 25, 2021
    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: 10867613
    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: May 15, 2018
    Date of Patent: December 15, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Michael Schnabel, Markovic Goran, Ralph Sperschneider, Jérémie Lecomte, Christian Helmrich
  • Publication number: 20200388293
    Abstract: A multi-channel audio decoder for providing at least two output audio signals on the basis of an encoded representation is configured to perform a weighted combination of a downmix signal, a decorrelated signal and a residual signal, to obtain one of the output audio signals. The multi-channel audio decoder is configured to determine a weight describing a contribution of the decorrelated signal in the weighted combination in dependence on the residual signal. A multi-channel audio encoder for providing an encoded representation of a multi-channel audio signal is configured to obtain a downmix signal on the basis of the multi-channel audio signal, to provide parameters describing dependencies between the channels of the multi-channel audio signal, and to provide a residual signal. The multi-channel audio encoder is configured to vary an amount of residual signal included into the encoded representation in dependence on the multi-channel audio signal.
    Type: Application
    Filed: August 25, 2020
    Publication date: December 10, 2020
    Applicant: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Sascha Dick, Christian Helmrich, Johannes Hilpert, Andreas Hoelzer
  • Publication number: 20200389673
    Abstract: Examples are provided for apparatus and methods for video encoding and decoding. An encoder apparatus for encoding a picture into a data stream is configured to: subject a transform of a block of the picture to quantization to obtain a quantized transform; determine a zero-quantized portion of the quantized transform; determine at least one noise parameter providing noise information on the transform within the zero-quantized portion; signal the quantized transform and the at least one parameter.
    Type: Application
    Filed: August 24, 2020
    Publication date: December 10, 2020
    Inventors: Christian HELMRICH, Paul KEYDEL, Sebastian BOSSE
  • Publication number: 20200389657
    Abstract: A video encoder encodes a video into a data stream, the video encoder being configured to vary a granularity at which a Quantization Parameter—QP—is applied depending on an association of frames of the video to temporally hierarchical layers at which the video is encoded into the data stream. The technology also concerns a respective decoder, a respective method for encoding and decoding, and a computer program for implementing the methods.
    Type: Application
    Filed: August 24, 2020
    Publication date: December 10, 2020
    Inventors: Christian HELMRICH, Heiko SCHWARZ, Detlev MARPE, Thomas WIEGAND, Adam WIECKOWSKI, Mischa SIEKMANN, Benjamin BROSS
  • Patent number: 10854208
    Abstract: An apparatus for decoding an encoded audio signal to obtain a reconstructed audio signal is provided. The apparatus includes a receiving interface, a delay buffer and a sample processor for processing the selected audio signal samples to obtain reconstructed audio signal samples of the reconstructed audio signal. The sample selector is configured to select, if a current frame is received by the receiving interface and if the current frame being received by the receiving interface is not corrupted, the plurality of selected audio signal samples from the audio signal samples being stored in the delay buffer depending on a pitch lag information being included by the current frame.
    Type: Grant
    Filed: May 23, 2018
    Date of Patent: December 1, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Michael Schnabel, Goran Markovic, Ralph Sperschneider, Jérémie Lecomte, Christian Helmrich
  • Publication number: 20200372923
    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: Application
    Filed: June 11, 2020
    Publication date: November 26, 2020
    Inventors: Christian HELMRICH, Bernd EDLER
  • Patent number: 10847167
    Abstract: An apparatus for generating a decoded two-channel signal includes: an audio processor for decoding an encoded two-channel signal to obtain a first set of first spectral portions; a parametric decoder for providing parametric data for a second set of second spectral portions and a two-channel identification identifying either a first or a second different two-channel representation for the second spectral portions; and a frequency regenerator for regenerating a second spectral portion depending on a first spectral portion of the first set of first spectral portions, the parametric data for the second portion and the two-channel identification for the second portion.
    Type: Grant
    Filed: October 10, 2018
    Date of Patent: November 24, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Sascha Disch, Frederik Nagel, Ralf Geiger, Balaji Nagendran Thoshkahna, Konstantin Schmidt, Stefan Bayer, Christian Neukam, Bernd Edler, Christian Helmrich
  • Patent number: 10839812
    Abstract: A multi-channel audio decoder for providing at least two output audio signals on the basis of an encoded representation is configured to perform a weighted combination of a downmix signal, a decorrelated signal and a residual signal, to obtain one of the output audio signals. The multi-channel audio decoder is configured to determine a weight describing a contribution of the decorrelated signal in the weighted combination in dependence on the residual signal. A multi-channel audio encoder for providing an encoded representation of a multi-channel audio signal is configured to obtain a downmix signal on the basis of the multi-channel audio signal, to provide parameters describing dependencies between the channels of the multi-channel audio signal, and to provide a residual signal. The multi-channel audio encoder is configured to vary an amount of residual signal included into the encoded representation in dependence on the multi-channel audio signal.
    Type: Grant
    Filed: January 22, 2016
    Date of Patent: November 17, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Sascha Dick, Christian Helmrich, Johannes Hilpert, Andreas Hoelzer
  • Publication number: 20200357418
    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 1, 2020
    Publication date: November 12, 2020
    Inventors: Sascha DICK, Christian HELMRICH, Nikolaus RETTELBACH, Florian SCHUH, Richard FUEG, Frederik NAGEL