US 12,230,285 B2
Audio entropy encoder/decoder with different spectral resolutions and transform lengths and upsampling and/or downsampling
Markus Multrus, Nuremberg (DE); Bernhard Grill, Lauf (DE); Guillaume Fuchs, Nuremberg (DE); Stefan Geyersberger, Wuerzburg (DE); Nikolaus Rettelbach, Nuremberg (DE); and Virgilio Bacigalupo, Nuremberg (DE)
Assigned to Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V., Munich (DE)
Filed by Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V., Munich (DE)
Filed on Apr. 5, 2024, as Appl. No. 18/628,556.
Application 18/628,556 is a continuation of application No. 18/301,191, filed on Apr. 14, 2023, granted, now 12,039,985.
Application 18/301,191 is a continuation of application No. 16/888,176, filed on May 29, 2020, granted, now 11,670,310, issued on Jun. 6, 2023.
Application 16/888,176 is a continuation of application No. 16/283,591, filed on Feb. 22, 2019, granted, now 10,685,659, issued on Jun. 16, 2020.
Application 16/283,591 is a continuation of application No. 14/589,881, filed on Jan. 5, 2015, granted, now 10,242,681, issued on Mar. 26, 2019.
Application 14/589,881 is a continuation of application No. 13/004,282, filed on Jan. 11, 2011, granted, now 8,930,202, issued on Jan. 6, 2015.
Application 13/004,282 is a continuation of application No. PCT/EP2009/003521, filed on May 18, 2009.
Claims priority of provisional application 61/103,820, filed on Oct. 8, 2008.
Claims priority of provisional application 61/079,842, filed on Jul. 11, 2008.
Prior Publication US 2024/0249734 A1, Jul. 25, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G10L 19/02 (2013.01); G10L 19/022 (2013.01); G10L 19/025 (2013.01); H03M 7/30 (2006.01); H03M 7/40 (2006.01)
CPC G10L 19/02 (2013.01) [G10L 19/022 (2013.01); H03M 7/30 (2013.01)] 2 Claims
OG exemplary drawing
 
1. Computer-implemented method for encoding a sampled audio signal into a data stream, comprising the steps of
spectrally decomposing, in a segment-wise manner and using different transform lengths, the sampled audio signal to obtain a sequence of segments of coefficients such that segments of coefficients for which different transform lengths are used, spectrally represent the sampled audio signal at different spectral resolutions and comprise different numbers of coefficients;
entropy encoding a currently encoded coefficient of a current segment having a first spectral resolution based on an entropy coding context derived from a previously encoded coefficient of a previous segment having a second spectral resolution, which is different from the first spectral resolution,
wherein the current segment is spectrally subdivided at the first spectral resolution into a first sequence of tuples of a first number spectrally neighboring coefficients,
wherein the previous segment is spectrally subdivided at the second spectral resolution into a second sequence of tuples of a second number of spectrally neighboring coefficients, the first number being equal to the second number,
computing the entropy coding context for a current tuple comprising the currently encoded coefficient by:
downsampling the second sequence of tuples of the previous segment when the second spectral resolution is finer than the first spectral resolution, and up-sampling the second sequence of tuples of the previous segment, when the second spectral resolution is coarser than the first spectral resolution so as to obtain a third sequence of tuples so that a tuple of the third sequence at an index k equals a tuple of the second sequence at an index k*ratio, wherein ratio corresponds to the second resolution divided by the first resolution,
selecting a set of tuples out of the third sequence, and
computing the entropy coding context for the current tuple on the basis of the set of tuples,
entropy encoding the currently encoded coefficient by entropy encoding the current tuple using the entropy coding context for the current tuple, and
signaling a predetermined flag in the data stream responsive to which the entropy coding context is to be reset.