Concept for coding mode switching compensation
First Claim
1. A decoder supporting, and being switchable between, at least two 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 responsive to a switching of one or more offrom a full-bandwidth audio coding mode to a BWE audio coding mode, andfrom a BWE audio coding mode to a full-bandwidth audio coding mode,wherein the high-frequency spectral band overlaps with the effective coded bandwidth of both coding modes between which the switching at the switching instance takes place, andthe high-frequency spectral band overlaps with a spectral BWE extension portion of the BWE audio coding mode anda transform spectrum portion or linear-predictively coded spectral portion of the full-bandwidth coding mode,wherein the decoder is configured to perform the temporal smoothing and/or blending at the transition by, within a temporary portion directly following the transition, crossing the transition or preceding the transition, decreasing an information signal'"'"'s energy during the temporary portion where the information signal is coded using the full-bandwidth audio coding mode and/or increasing the information signal'"'"'s energy during the temporary portion where the information signal is coded using the BWE audio coding mode so as to compensate for an increased energy preserving property of the full-bandwidth audio coding mode relative to the BWE audio coding mode.
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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.
23 Citations
18 Claims
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1. A decoder supporting, and being switchable between, at least two 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 responsive to a switching of one or more of from a full-bandwidth audio coding mode to a BWE audio coding mode, and from a BWE audio coding mode to a full-bandwidth audio coding mode, wherein the high-frequency spectral band overlaps with the effective coded bandwidth of both coding modes between which the switching at the switching instance takes place, and the high-frequency spectral band overlaps with a spectral BWE extension portion of the BWE audio coding mode and a transform spectrum portion or linear-predictively coded spectral portion of the full-bandwidth coding mode, wherein the decoder is configured to perform the temporal smoothing and/or blending at the transition by, within a temporary portion directly following the transition, crossing the transition or preceding the transition, decreasing an information signal'"'"'s energy during the temporary portion where the information signal is coded using the full-bandwidth audio coding mode and/or increasing the information signal'"'"'s energy during the temporary portion where the information signal is coded using the BWE audio coding mode so as to compensate for an increased energy preserving property of the full-bandwidth audio coding mode relative to the BWE audio coding mode.
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8. A decoder supporting, and being switchable between, at least two 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 additionally depending on an analysis of the information signal in an analysis spectral band arranged spectrally below the high-frequency spectral band, wherein the decoder is configured to determine a measure for an information signal'"'"'s energy fluctuation in the analysis spectral band and set a degree of the temporal smoothing and/or blending dependent on the measure.
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16. A method for decoding supporting, and being switchable between, at least two 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 decoding is performed responsive to a switching of one or more of from a full-bandwidth audio coding mode to a BWE audio coding mode, and from a BWE audio coding mode to a full-bandwidth audio coding mode, wherein the high-frequency spectral band overlaps with the effective coded bandwidth of both coding modes between which the switching at the switching instance takes place, and the high-frequency spectral band overlaps with a spectral BWE extension portion of the BWE audio coding mode and a transform spectrum portion or linear-predictively coded spectral portion of the full-bandwidth coding mode, wherein the temporal smoothing and/or blending at the transition is performed by, within a temporary portion directly following the transition, crossing the transition or preceding the transition, decreasing an information signal'"'"'s energy during the temporary portion where the information signal is coded using the full-bandwidth audio coding mode and/or increasing the information signal'"'"'s energy during the temporary portion where the information signal is coded using the BWE audio coding mode so as to compensate for an increased energy preserving property of the full-bandwidth audio coding mode relative to the BWE audio coding mode.
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18. 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, encode the information signal temporally smoothened and/or blended 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 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 monotonically increasing from the transition towards farther away from the transition till 1.
Specification