Patents by Inventor Eleni FOTOPOULOU

Eleni FOTOPOULOU 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: 20210104249
    Abstract: A multisignal encoder for encoding at least three audio signals, including: a signal preprocessor for individually preprocessing each audio signal to obtain at least three preprocessed audio signals, wherein the preprocessing is performed so that a preprocessed audio signal is whitened with respect to the signal before preprocessing; an adaptive joint signal processor for performing a processing of the at least three preprocessed audio signals to obtain at least three jointly processed signals or at least two jointly processed signals and an unprocessed signal; a signal encoder for encoding each signal to obtain one or more encoded signals; and an output interface for transmitting or storing an encoded multisignal audio signal including the one or more encoded signals, side information relating to the preprocessing and side information relating to the processing.
    Type: Application
    Filed: December 17, 2020
    Publication date: April 8, 2021
    Inventors: Eleni FOTOPOULOU, Markus Multrus, Sascha Dick, Goran Markovic, Pallavi Maben, Srikanth Korse, Stefan Bayer, Sascha Disch, Jürgen Herre
  • Publication number: 20210098007
    Abstract: In multichannel audio coding, improved computational efficiency is achieved by computing comparison parameters for ITD compensation between any two channels in the frequency domain for a parametric audio encoder. This may mitigate negative effects on encoder parameter estimates.
    Type: Application
    Filed: December 15, 2020
    Publication date: April 1, 2021
    Inventors: Jan BÜTHE, Eleni FOTOPOULOU, Srikanth KORSE, Pallavi MABEN, Markus MULTRUS, Franz REUTELHUBER
  • Publication number: 20210065722
    Abstract: The invention refers to audio encoders, audio decoders, and audio encoding methods and audio decoding methods. In some examples, the invention refers to improved stereo coding. An encoder provides an encoded representation of an audio signal. The encoder applies a spectral whitening to a separate-channel representation of the input audio signal, to obtain a whitened separate-channel representation of the signal. The audio encoder applies a spectral whitening to a mid-side representation of the signal, to obtain a whitened mid-side representation of the signal. The audio encoder decides whether to encode the whitened separate-channel representation of the signal, to obtain the encoded representation of the signal, or to encode the whitened mid-side representation of the signal, to obtain the encoded representation of the signal.
    Type: Application
    Filed: August 28, 2020
    Publication date: March 4, 2021
    Inventors: Goran MARKOVIC, Sascha DICK, Eleni FOTOPOULOU, Stefan BAYER
  • Publication number: 20210012784
    Abstract: An apparatus for estimating an inter-channel time difference between a first channel signal and a second channel signal, includes a signal analyzer for estimating a signal characteristic of the first channel signal or the second channel signal or both signals or a signal derived from the first channel signal or the second channel signal; a calculator for calculating a cross-correlation spectrum for a time block from the first channel signal in the time block and the second channel signal in the time block; a weighter for weighting a smoothed or non-smoothed cross-correlation spectrum to obtain a weighted cross correlation spectrum using a first weighting procedure or using a second weighting procedure depending on a signal characteristic estimated by the signal analyzer, wherein the first weighting procedure is different from the second weighting procedure; and a processor for processing the weighted cross-correlation spectrum to obtain the inter-channel time difference.
    Type: Application
    Filed: September 29, 2020
    Publication date: January 14, 2021
    Inventors: Eleni FOTOPOULOU, Jan BÜTHE, Emmanuel RAVELLI, Pallavi MABEN, Martin DIETZ, Franz REUTELHUBER, Stefan DÖHLA, Srikanth KORSE
  • Patent number: 10861468
    Abstract: The apparatus for encoding a multi-channel signal having at least two channels, includes: a parameter determiner for determining a broadband alignment parameter and a plurality of narrowband alignment parameters from the multichannel signal; a signal aligner for aligning the at least two channels using the broadband alignment parameter and the plurality of narrowband alignment parameters to obtain aligned channels; a signal processor for calculating a mid-signal and a side signal using the aligned channels; a signal encoder for encoding the mid-signal to obtain an encoded mid-signal and for encoding the side signal to obtain an encoded side signal; and an output interface for generating an encoded multi-channel signal including the encoded mid-signal, the encoded side signal, information on the broadband alignment parameter and information on the plurality of narrowband alignment parameters.
    Type: Grant
    Filed: July 12, 2018
    Date of Patent: December 8, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Stefan Bayer, Eleni Fotopoulou, Markus Multrus, Guillaume Fuchs, Emmanuel Ravelli, Markus Schnell, Stefan Doehla, Wolfgang Jaegers, Martin Dietz, Goran Markovic
  • Patent number: 10854211
    Abstract: An apparatus for encoding a multi-channel signal including at least two channels includes a time-spectral converter for converting sequences of blocks of sampling values of the at least two channels into a frequency domain representation having sequences of blocks of spectral values for the at least two channels; a multi-channel processor for applying a joint multi-channel processing to the sequences of blocks of spectral values to obtain at least one result sequence of blocks of spectral values including information related to the at least two channels; a spectral-time converter for converting the result sequence of blocks of spectral values into a time domain representation including an output sequence of blocks of sampling values; and a core encoder for encoding the output sequence of blocks of sampling values to obtain an encoded multi-channel signal.
    Type: Grant
    Filed: April 4, 2019
    Date of Patent: December 1, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Guillaume Fuchs, Emmanuel Ravelli, Markus Multrus, Markus Schnell, Stefan Doehla, Martin Dietz, Goran Markovic, Eleni Fotopoulou, Stefan Bayer, Wolfgang Jaegers
  • Publication number: 20200335116
    Abstract: A codec allowing for switching between different coding modes is improved by, responsive to a switching instance, performing temporal smoothing and/or blending at a respective transition.
    Type: Application
    Filed: June 29, 2020
    Publication date: October 22, 2020
    Inventors: Martin DIETZ, Eleni FOTOPOULOU, Jérémie LECOMTE, Markus MULTRUS, Benjamin SCHUBERT
  • Patent number: 10734007
    Abstract: A codec allowing for switching between different coding modes is improved by, responsive to a switching instance, performing temporal smoothing and/or blending at a respective transition.
    Type: Grant
    Filed: January 17, 2018
    Date of Patent: August 4, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Martin Dietz, Eleni Fotopoulou, Jérémie Lecomte, Markus Multrus, Benjamin Schubert
  • Publication number: 20200227059
    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: Application
    Filed: March 31, 2020
    Publication date: July 16, 2020
    Inventors: Emmanuel RAVELLI, Stefan DOEHLA, Guillaume FUCHS, Eleni FOTOPOULOU, Christian HELMRICH
  • Patent number: 10706861
    Abstract: An apparatus for estimating an inter-channel time difference between a first channel signal and a second channel signal, includes: a calculator for calculating a cross-correlation spectrum for a time block from the first channel signal in the time block and the second channel signal in the time block; a spectral characteristic estimator for estimating a characteristic of a spectrum of the first channel signal or the second channel signal for the time block; a smoothing filter for smoothing the cross-correlation spectrum over time using the spectral characteristic to obtain a smoothed cross-correlation spectrum; and a processor for processing the smoothed cross-correlation spectrum to obtain the inter-channel time difference.
    Type: Grant
    Filed: July 13, 2018
    Date of Patent: July 7, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der andgewandten Forschung e.V.
    Inventors: Stefan Bayer, Eleni Fotopoulou, Markus Multrus, Guillaume Fuchs, Emmanuel Ravelli, Markus Schnell, Stefan Doehla, Wolfgang Jaegers, Martin Dietz, Goran Markovic
  • Publication number: 20200194013
    Abstract: An apparatus for estimating an inter-channel time difference between a first channel signal and a second channel signal, includes: a calculator for calculating a cross-correlation spectrum for a time block from the first channel signal in the time block and the second channel signal in the time block; a spectral characteristic estimator for estimating a characteristic of a spectrum of the first channel signal or the second channel signal for the time block; a smoothing filter for smoothing the cross-correlation spectrum over time using the spectral characteristic to obtain a smoothed cross-correlation spectrum; and a processor for processing the smoothed cross-correlation spectrum to obtain the inter-channel time difference.
    Type: Application
    Filed: February 19, 2020
    Publication date: June 18, 2020
    Inventors: Stefan BAYER, Eleni FOTOPOULOU, Markus MULTRUS, Guillaume FUCHS, Emmanuel RAVELLI, Markus SCHNELL, Stefan DOEHLA, Wolfgang JAEGERS, Martin DIETZ, Goran MARKOVIC
  • Patent number: 10622000
    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: October 1, 2018
    Date of Patent: April 14, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Emmanuel Ravelli, Stefan Doehla, Guillaume Fuchs, Eleni Fotopoulou, Christian Helmrich
  • Publication number: 20200051578
    Abstract: A downscaled version of an audio decoding procedure may more effectively and/or at improved compliance maintenance be achieved if the synthesis window used for downscaled audio decoding is a downsampled version of a reference synthesis window involved in the non-downscaled audio decoding procedure by downsampling by the downsampling factor by which the downsampled sampling rate and the original sampling rate deviate, and downsampled using a segmental interpolation in segments of 1/4 of the frame length.
    Type: Application
    Filed: August 23, 2019
    Publication date: February 13, 2020
    Inventors: Markus SCHNELL, Manfred LUTZKY, Eleni FOTOPOULOU, Konstantin SCHMIDT, Conrad BENNDORF, Adrian TOMASEK, Tobias ALBERT, Timon SEIDL
  • Patent number: 10535356
    Abstract: An apparatus for encoding a multi-channel signal having at least two channels is provided. The apparatus includes a time-spectral converter, converting sequences of blocks of sample values of the two channels into a frequency domain representation having sequences of blocks of spectral values for the two channels, a block of sampling values having an associated input sampling rate, a block of spectral values of the sequences of blocks that has spectral values up to a maximum input frequency related to the input sampling rate; a multi-channel processor to obtain a result sequence of blocks of spectral values having information related to the two channels; a spectral domain resampler to obtain a resampled sequence of blocks of spectral values; a spectral-time converter for converting the resampled sequence of blocks into a time domain representation; and a core encoder for encoding the output sequence of blocks to obtain an encoded multi-channel signal.
    Type: Grant
    Filed: November 22, 2017
    Date of Patent: January 14, 2020
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Guillaume Fuchs, Emmanuel Ravelli, Markus Multrus, Markus Schnell, Stefan Doehla, Martin Dietz, Goran Markovic, Eleni Fotopoulou, Stefan Bayer, Wolfgang Jaegers
  • Patent number: 10431230
    Abstract: A downscaled version of an audio decoding procedure may more effectively and/or at improved compliance maintenance be achieved if the synthesis window used for downscaled audio decoding is a downsampled version of a reference synthesis window involved in the non-downscaled audio decoding procedure by downsampling by the downsampling factor by which the downsampled sampling rate and the original sampling rate deviate, and downsampled using a segmental interpolation in segments of ¼ of the frame length.
    Type: Grant
    Filed: December 15, 2017
    Date of Patent: October 1, 2019
    Assignee: Fraunhofer-Gesellschaft zur Foerderung de angewandten forschung e.V.
    Inventors: Markus Schnell, Manfred Lutzky, Eleni Fotopoulou, Konstantin Schmidt, Conrad Benndorf, Adrian Tomasek, Tobias Albert, Timon Seidl
  • Patent number: 10424309
    Abstract: An apparatus for encoding a multi-channel signal including at least two channels includes a time-spectral converter for converting sequences of blocks of sampling values of the at least two channels into a frequency domain representation having sequences of blocks of spectral values for the at least two channels; a multi-channel processor for applying a joint multi-channel processing to the sequences of blocks of spectral values to obtain at least one result sequence of blocks of spectral values including information related to the at least two channels; a spectral-time converter for converting the result sequence of blocks of spectral values into a time domain representation including an output sequence of blocks of sampling values; and a core encoder for encoding the output sequence of blocks of sampling values to obtain an encoded multi-channel signal.
    Type: Grant
    Filed: July 13, 2018
    Date of Patent: September 24, 2019
    Assignee: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
    Inventors: Guillaume Fuchs, Emmanuel Ravelli, Markus Multrus, Markus Schnell, Stefan Doehla, Martin Dietz, Goran Markovic, Eleni Fotopoulou, Stefan Bayer, Wolfgang Jaegers
  • Publication number: 20190259395
    Abstract: An apparatus for downmixing a multi-channel signal having at least two channels, has: a downmixer for calculating a downmix signal from the multi-channel signal, wherein the downmixer is configured to calculate the downmix using an absolute phase compensation, so that a channel having a lower energy among the at least two channels is only rotated or is rotated stronger than a channel having a greater energy in calculating the downmix signal; and an output interface for generating an output signal, the output signal having information on the downmix signal.
    Type: Application
    Filed: May 3, 2019
    Publication date: August 22, 2019
    Inventors: Jan BUETHE, Guillaume FUCHS, Wolfgang JAEGERS, Franz REUTELHUBER, Juergen HERRE, Eleni FOTOPOULOU, Markus MULTRUS, Srikanth KORSE
  • Publication number: 20190259398
    Abstract: An apparatus for encoding a multi-channel signal having at least two channels, has: a downmixer for calculating a downmix signal from the multi-channel signal; a parameter calculator for calculating a side gain from a first channel of the at least two channels and a second channel of the at least two channels and for calculating a residual gain from the first channel and the second channel; and an output interface for generating an output signal, the output signal having information on the downmix signal, and on the side gain and the residual gain.
    Type: Application
    Filed: May 7, 2019
    Publication date: August 22, 2019
    Inventors: Jan BUETHE, Guillaume FUCHS, Wolfgang JAEGERS, Franz REUTELHUBER, Juergen HERRE, Eleni FOTOPOULOU, Markus MULTRUS, Srikanth KORSE
  • Publication number: 20190228786
    Abstract: An apparatus for encoding a multi-channel signal including at least two channels includes a time-spectral converter for converting sequences of blocks of sampling values of the at least two channels into a frequency domain representation having sequences of blocks of spectral values for the at least two channels; a multi-channel processor for applying a joint multi-channel processing to the sequences of blocks of spectral values to obtain at least one result sequence of blocks of spectral values including information related to the at least two channels; a spectral-time converter for converting the result sequence of blocks of spectral values into a time domain representation including an output sequence of blocks of sampling values; and a core encoder for encoding the output sequence of blocks of sampling values to obtain an encoded multi-channel signal.
    Type: Application
    Filed: April 4, 2019
    Publication date: July 25, 2019
    Inventors: Guillaume FUCHS, Emmanuel RAVELLI, Markus MULTRUS, Markus SCHNELL, Stefan DOEHLA, Martin DIETZ, Goran MARKOVIC, Eleni FOTOPOULOU, Stefan BAYER, Wolfgang JAEGERS
  • Publication number: 20190103121
    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: Application
    Filed: October 1, 2018
    Publication date: April 4, 2019
    Inventors: Emmanuel RAVELLI, Stefan DOEHLA, Guillaume FUCHS, Eleni FOTOPOULOU, Christian HELMRICH