US 12,488,804 B2
Frequency-domain audio coding supporting transform length switching
Sascha Dick, Nuremberg (DE); Christian Helmrich, Erlangen (DE); and Andreas Hoelzer, Erlangen (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 Dec. 14, 2023, as Appl. No. 18/540,819.
Application 18/540,819 is a continuation of application No. 17/227,178, filed on Apr. 9, 2021, granted, now 11,862,182.
Application 17/227,178 is a continuation of application No. 16/284,534, filed on Feb. 25, 2019, granted, now 10,984,809, issued on Apr. 20, 2021.
Application 16/284,534 is a continuation of application No. 15/004,563, filed on Jan. 22, 2016, granted, now 10,242,682, issued on Mar. 26, 2019.
Application 15/004,563 is a continuation of application No. PCT/EP2014/065169, filed on Jul. 15, 2014.
Claims priority of application No. 13177373 (EP), filed on Jul. 22, 2013; and application No. 13189334 (EP), filed on Oct. 18, 2013.
Prior Publication US 2024/0127836 A1, Apr. 18, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. G10L 19/022 (2013.01); G10L 19/03 (2013.01); G10L 19/008 (2013.01); G10L 19/028 (2013.01)
CPC G10L 19/022 (2013.01) [G10L 19/03 (2013.01); G10L 19/008 (2013.01); G10L 19/028 (2013.01)] 11 Claims
OG exemplary drawing
 
1. An audio decoder, comprising an electronic circuit, programmed computer or microprocessor configured to:
extract a sequence of frequency-domain coefficients relating to a frame of an audio signal from a data stream;
extract scale factors for the frame from the data stream;
subject the frequency-domain coefficients, scaled according to the scale factors, to inverse transformation to obtain a time-domain portion of the audio signal corresponding to the frame;
subject the time-domain portion to an overlap-add process to obtain the audio signal,
wherein the audio decoder is responsive to a signalization within the data stream for the frame of the audio signal so as to, depending on the signalization,
form one transform out of the sequence of frequency-domain coefficients by maintaining a sequential order of the frequency-domain coefficients in the sequence of frequency-domain coefficients and subject the one transform, scaled according to the scale factors, to an inverse transformation of a first transform length, or
form more than one transform by de-interleaving the frequency-domain coefficients from the sequence of frequency-domain coefficients and subject, scaled according to the scale factors, each of the more than one transforms to an inverse transformation of a second transform length, shorter than the first transform length,
wherein the frequency-domain coefficients are grouped into a number of scale factor bands which is independent from the signalization, and a scale factor is extracted from the data stream for each scale factor band.