Concept for coding mode switching compensation
AssigneeFraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V.
InventorsMartin Dietz, Eleni Fotopoulou, Jérémie Lecomte, Markus Multrus, Benjamin Schubert
Life of this patent
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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.
Claims18
Decoder supporting, and being switchable between, at least two audio coding modes so as to decode an information signal, wherein the decoder is configured to, responsive to a switching instance, perform temporal smoothing and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band,
- wherein the decoder is configured to perform the temporal smoothing and/or blending at the transition by, within a temporary phase which directly follows the transition, crosses the transition or precedes the transition, decreasing an information signal's energy during the temporary portion where the information signal is coded using a first audio coding mode and/or increasing the information signal's energy during the temporary portion (80) where the information signal is coded using a second audio coding mode, wherein the first audio coding mode has an higher energy preserving property compared to the second audio coding mode.
Decoder supporting, and being switchable between, at least two audio coding modes so as to decode an information signal, wherein the decoder is configured to, responsive to a switching instance, perform temporal smoothing and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band, wherein the decoder is configured to scale the information signals energy in the high-frequency spectral band in the second temporal portion with a scaling factor which varies between 1 and
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The decoder supporting, and being switchable between, at least two audio coding modes so as to decode an information signal, wherein the decoder is configured to, responsive to a switching instance, perform temporal smoothing and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band, wherein the decoder is configured to perform the switching and/or blending by applying blind BWE onto one of the first and second temporal portions, decoded using a second audio coding mode having an effective coded bandwidth smaller than an effective coded bandwidth of a first audio coding mode using which the other one of the first and second temporal portions is decoded, so as to spectrally extend the effective coded bandwidth of the one of the first and second temporal portions into the high-frequency spectral band and temporally shape the information signal's energy in the high-frequency spectral band in the one of the first and second temporal portions, as spectrally extended, according to a fade-in/out scaling function decreasing from the transition towards farther away from the transition.
Decoder supporting, and being switchable between, at least two audio coding modes so as to decode an information signal, wherein the decoder is configured to, responsive to a switching instance, perform temporal smoothing and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band, wherein the switching switches from a first audio coding mode to a second audio coding mode with the first audio coding mode having an effective coded bandwidth greater than an effective coded bandwidth of the second audio coding mode, wherein the decoder is configured to spectrally extend, using blind BWE, the effective coded bandwidth of the second temporal portion into the high-frequency spectral band and temporally shape the information signal's energy in the high-frequency spectral band in the second temporal portion, as spectrally extended using the blind BWE, according to a fade-out scaling function decreasing from the transition towards farther away from the transition.
Decoder supporting, and being switchable between, at least two audio coding modes so as to decode an information signal, wherein the decoder is configured to, responsive to a switching instance, perform temporal smoothing and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band, wherein the switching switches from a second audio coding mode to a first audio coding mode wherein an effective coded bandwidth of the second audio coding mode is smaller than an effective coded bandwidth of the first audio coding mode, wherein the decoder is configured to temporally shape an information signal's energy in the high-frequency spectral band in the second temporal portion according to a fade-in scaling function increasing from the transition towards farther away from the transition.
Decoder supporting, and being switchable between, at least two audio coding modes so as to decode an information signal, wherein the decoder is configured to, responsive to a switching instance, perform temporal smoothing and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band, wherein the decoder is configured to perform the temporal smoothing and/or blending at the switching instance by applying a fade-in or fade-out scaling function and to, if a subsequent switching instance occurs during the fade-in or fade-out scaling function, apply, again, a fade-in or fade-out scaling function to a high-frequency spectral band so as to perform temporal smoothing and/or blending at the subsequent switching instance, with setting a starting point of applying the fade-in or fade-out scaling function from the subsequent switching instance on such that the fade-in or fade-out scaling function applied at the subsequent switching instance is, at the starting point, a function value nearest to a function value assumed by the fade-in or fade-out scaling function when being applied at the switching instance, at the time of occurrance of the subsequent switching instance.
Method for decoding supporting, and being switchable between, at least two audio coding modes so as to decode an information signal, wherein the method comprises, responsive to a switching instance, performing temporal smoothing and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band,
- wherein the temporal smoothing and/or blending at the transition is performed by, within the temporary phase which directly follows the transition, crosses the transition or precedes the transition, decreasing an information signal's energy during the temporary portion where the information signal is coded using a first audio coding mode and/or increasing the information signal's energy during the temporary portion (80) where the information signal is coded using a second audio coding mode, wherein the first audio coding mode has an higher energy preserving property compared to the second audio coding mode.
An encoder supporting, and being switchable between, at least two modes of different signal-energy-conservation property in a high-frequency spectral band, so as to encode an information signal, wherein the encoder is configured to, responsive to a switching instance, process the information signal by temporally smoothing and/or blending the information signal at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band to obtain a pre-processed version of the information signal, and encode the pre-processed version of the information signal,
- wherein the encoder is configured to, responsive to a switching instance from a first coding mode comprising a first signal-energy-conservation property in the high-frequency spectral band to a second coding mode comprising a second signal-energy-conservation property in the high-frequency spectral band, temporary encode a modified version of the information signal which is modified compared to the information signal in that an information signal's energy in the high-frequency spectral band in a temporal portion succeeding the switching instance is temporally shaped according to a fade-in scaling function increasing from the transition towards farther away from the transition.
A method for encoder supporting, and being switchable between, at least two modes of different signal-energy-conservation property in a high-frequency spectral band, so as to encode an information signal, wherein the method comprises, responsive to a switching instance, processing by temporally smoothing the information signal and/or blending at a transition between a first temporal portion of the information signal, preceding the switching instance, and a second temporal portion of the information signal, succeeding the switching instance, in a manner confined to a high-frequency spectral band to obtain a pre-processed version of the information signal, and encoding the pre-processed version of the information signal,
- wherein the method comprises, responsive to a switching instance from a first coding mode comprising a first signal-energy-conservation property in the high-frequency spectral band to a second coding mode comprising a second signal-energy-conservation property in the high-frequency spectral band, temporarily encoding a modified version of the information signal which is modified compared to the information signal in that an information signal's energy in the high-frequency spectral band in a temporal portion succeeding the switching instance is temporally shaped according to a fade-in scaling function increasing from the transition towards farther away from the transition.
Dependencies are inferred from the claim text.