Device for perceptual weighting in audio encoding/decoding
First Claim
1. A perceptual weighting device for coding/decoding of an audio signal in a given frequency band, said coding/decoding being effected in a plurality of adjacent sub-bands in said given frequency band, wherein said device includes, in at least one sub-band of the plurality of adjacent sub-bands, a perceptually weighted filter with gain compensation, said perceptually weighted filter with gain compensation being in the form of fac*Â
- (z/γ
1)/Â
(z/γ
2) where Â
(z) represents a linear prediction filter, with 0≦
γ
2≦
1 and 0≦
γ
1≦
1, and fac represents a gain compensation factor which is a function of coefficients of said linear prediction filter Â
(z), the gain compensation being adapted to realize spectral continuity between an output signal of said perceptually weighted filter with gain compensation and signals in sub-bands adjacent to said at least one sub-band, said gain compensation factor fac being given by;
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Accused Products
Abstract
A hierarchical audio coder for use in a frequency band divided into adjacent first and second sub-bands, the coder including: a core coder (305) for coding an original signal in the first sub-band of the frequency band; a stage (306) for calculating a residual signal (e) from the original signal and the signal from the core coder; a device (307) for perceptually weighting the residual signal (e). The perceptual weighting device includes a perceptually weighted filter (307) with gain compensation adapted to realize spectral continuity between the output signal of the perceptually weighted filter with gain compensation and the signal in the second sub-band. Application to transmitting and storing digital signals, such as audio-frequency speech, music, etc. signals.
19 Citations
24 Claims
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1. A perceptual weighting device for coding/decoding of an audio signal in a given frequency band, said coding/decoding being effected in a plurality of adjacent sub-bands in said given frequency band, wherein said device includes, in at least one sub-band of the plurality of adjacent sub-bands, a perceptually weighted filter with gain compensation, said perceptually weighted filter with gain compensation being in the form of fac*Â
- (z/γ
1)/Â
(z/γ
2) where Â
(z) represents a linear prediction filter, with 0≦
γ
2≦
1 and 0≦
γ
1≦
1, and fac represents a gain compensation factor which is a function of coefficients of said linear prediction filter Â
(z), the gain compensation being adapted to realize spectral continuity between an output signal of said perceptually weighted filter with gain compensation and signals in sub-bands adjacent to said at least one sub-band, said gain compensation factor fac being given by;
- View Dependent Claims (2, 3, 4, 5)
- (z/γ
-
6. A hierarchical audio coder for use in a frequency band divided into adjacent first and second sub-bands, said coder comprising:
-
a core coder configured to code an original signal in a first sub-band of said frequency band; a stage configured to calculate a residual signal from said original signal and the coded original signal from said core coder; a perceptual weighting device configured to perceptually weight said residual signal; wherein said perceptual weighting device includes a perceptually weighted filter with gain compensation, said perceptually weighted filter with gain compensation being in the form of fac1*Â
1(z/γ
1)/Â
1(z/γ
2) where Â
1(z) represents a linear prediction filter, with 0≦
γ
2≦
1 and 0≦
γ
1≦
1, and fac1 represents a gain compensation factor which is a function of coefficients of said linear prediction filter Â
1(z), the gain compensation being adapted to realize spectral continuity between an output signal of said perceptually weighted filter with gain compensation and a signal in the second sub band, said gain compensation factor being given by; - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A hierarchical audio decoder for use in a frequency band divided into adjacent first and second sub-bands, said decoder comprising:
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a core decoder adapted to decode in the first sub-band of said frequency band a received signal coded by a core coder; and an inverse perceptual weighting device for inversely perceptually weighting a signal representing the residual signal weighted in the first sub-band by the perceptual weighting device of said coder; wherein said inverse perceptual weighting device includes a perceptually weighted filter with gain compensation that is the inverse of the perceptually weighted filter with gain compensation of the coder in the first sub-band, wherein the perceptually weighted filter with gain compensation of the inverse perceptual weighting device is in the form (1/fac1)*Â
1(z/γ
2)/Â
1(z/γ
1) where Â
1(z) represents a linear prediction filter, with 0≦
γ
2≦
1 and 0≦
γ
1≦
1, and 1/fac1 represents a gain compensation factor which is a function of coefficients of said linear prediction filter Â
1(z), given by; - View Dependent Claims (19, 20, 21, 22)
-
-
23. A perceptual weighting method of coding an audio signal in a given frequency band, said coding being effected in a plurality of adjacent sub-bands in said frequency band, wherein said method includes, in at least one sub-band of the plurality of adjacent sub-bands, a step of perceptual weighted filtering with gain compensation, said perceptual weighted filtering with gain compensation being in the form of fac*Â
- (z/γ
1)/Â
(z/γ
2) where Â
(z) represents a linear prediction filter, with 0≦
γ
2≦
1 and 0≦
γ
1≦
1, and fac represents a gain compensation factor which is a function of coefficients of said linear prediction filter Â
(z), the gain compensation being adapted to realize spectral continuity between an output signal of said perceptually weighted filter with gain compensation and signals in sub-bands adjacent to said at least one sub-band, said gain compensation factor fac being given by;
- View Dependent Claims (24)
- (z/γ
Specification