US 8,144,879 B2 · Method, device, encoder apparatus, decoder apparatus and audio system

Abstract

A method and a device are described for processing a stereo signal obtained from an encoder, which encodes an N-channel audio signal into spatial parameters (P) and a stereo down-mix comprising first and second stereo signals (LO, RO). A first signal and a third signal are added in order to obtain a first output signal (L0w), wherein the first signal (L0wL) comprises the first stereo signal (LO) modified by a first complex function (g1), and the third signal (L0wR) comprises the second stereo signal (RO) modified by a third complex function (g3). A second signal and a fourth signal are added to obtain a second output signal (R0w). The fourth signal (R0wR) comprises the second stereo signal (RO) modified by a fourth complex function (g4), and the second signal (R0wL) comprises the first stereo signal (LO) modified by a second complex function (g2). The complex functions (g1, g2, g3, g4) are functions of the spatial parameters (P) and are chosen to be such that an energy value of the difference (L0wL,R0wL) between the first signal and the second signal is larger than or equal to the energy value of the sum (L0wL+R0wL) of the first and the second signal, and the energy value of the difference (R0wR−L0wR) between the fourth signal and the third signal is larger than or equal to the energy value of the sum (R0wR+L0wR) of the fourth signal and the third signal.

Claims14

Dependent claims

A method of processing a stereo signal obtained from an encoder, which encodes an N-channel audio signal into spatial parameters and a stereo down-mix signal comprising first and second stereo signals, the method comprising the steps of:

adding a first signal and a third signal to obtain a first output signal, wherein said first signal comprises said first stereo signal modified by a first complex function, and wherein said third signal comprises said second stereo signal modified by a third complex function;
and
adding a second signal and a fourth signal to obtain a second output signal, wherein said fourth signal comprises said second stereo signal modified by a fourth complex function and wherein said second signal comprises said first stereo signal modified by a second complex function;
wherein said first function comprises first and second function parts wherein the output of said second function part increases when said spatial parameters indicate that a contribution of the rear channels in said first stereo signal increases as compared to the contribution of the front channels in said first stereo signal, and said second function part comprises a phase shift which is substantially equal to plus or minus 90 degrees.

1 more element

A device for processing a stereo signal obtained from an encoder, which encodes an N-channel audio signal into spatial parameters and a stereo down-mix signal comprising first and second stereo signals, the device comprising:

first adding means for adding a first signal and a third signal to obtain a first output signal, wherein said first signal comprises said first stereo signal modified by a first complex function, and wherein said third signal comprises said second stereo signal modified by a third complex function;
and
second adding means for adding a second signal and a fourth signal to obtain a second output signal, wherein said fourth signal comprises said second stereo signal modified by a fourth complex function, and wherein said second signal comprises said first stereo signal modified by a second complex function;
wherein said first function comprises first and second function parts, wherein the output of said second function part increases when said spatial parameters indicate that a contribution of the rear channels in said first stereo signal increases as compared to the contribution of the front channels in said first stereo signal, and said second function part comprises a phase shift which is substantially equal to plus or minus 90 degrees.

1 more element

Dependencies are inferred from the claim text.

Method, device, encoder apparatus, decoder apparatus and audio system

Life of this patent

Method, device, encoder apparatus, decoder apparatus and audio system

Life of this patent

Abstract

Claims14