Reduced Number of Channels Decoding

Abstract

An intermediate channel representation of a multi-channel signal can be reconstructed highly efficient and with high fidelity, when upmix parameters for upmixing a transmitted downmix signal to the intermediate channel representation are derived that allow for an upmix using the same upmixing algorithms as within the multi-channel reconstruction. This can be achieved when a parameter re-calculator is used to derive the upmix parameters that takes into account also parameters having information on channels that are not included in the intermediate channel representation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the present invention are subsequently described by referring to the enclosed drawings, wherein:

FIG. 1 shows examples for tree-based parameterizations;

FIG. 2 shows examples for tree-structured decoding schemes;

FIG. 3 shows an example of a prior-art multi-channel encoder;

FIG. 4 shows examples of prior-art decoders;

FIG. 5 shows an example for prior-art stereo reconstruction of a downmix multi-channel signal;

FIG. 6 shows a block diagram of an example of an inventive parameter calculator;

FIG. 7 shows an example for an inventive channel reconstructor; and

FIG. 8 shows an example for an inventive receiver or audio player.

Claims

1. Parameter calculator for deriving upmix parameters for upmixing a downmix signal into an intermediate channel representation of a multi-channel signal having more channels than the downmix signal and less channels than the multi-channel signal, the downmix signal having associated thereto multi-channel parameters describing spatial properties of the multi-channel signal, wherein the multi-channel signal includes channels not included in the intermediate channel representation and wherein the multi-channel parameters include information on the channels not included in the intermediate channel representation, the parameter calculator comprising: a parameter recalculator for deriving the upmix parameters from the multi-channel parameters using the parameters having information on channels not included in the intermediate channel representation.

2. Parameter calculator in accordance with claim 1, in which the parameter recalculator is adapted to use multi-channel parameters describing signal properties of a channel or a combination of channels of the multi-channel signal with respect to another channel or another combination of channels of the multi-channel signal.

3. Parameter calculator in accordance with claim 2, in which the parameter recalculator is operative to derive upmix parameters describing the same signal properties of the channels of the intermediate channel representation as the multi-channel parameters.

4. Parameter calculator in accordance with claim 1, in which the parameter recalculator is adapted to use correlation parameters (ICC) having information on a correlation and level parameters (CLD) having energy information for a channel or a combination of channels of the multi-channel signal with respect to another channel or another combination of channels of a multi-channel signal.

5. Parameter calculator in accordance with claim 4, adapted to use multi-channel parameters for a multi-channel signal comprising a left front (LF), a left surround (LS), a right front (RF), a right surround (RS) and a center channel (C), in which the parameter recalculator is operative to derive upmix parameters for an intermediate channel representation having two channels, the upmix parameters including one CLD parameter and one ICC parameter.

6. Parameter calculator in accordance with claim 5, in which the parameter recalculator is operative to derive the CLD parameter having energy information for a left and a right channel of the intermediate channel representation using: a first CLD parameter (CLD0) having energy information for a combination of the LF and LR channel and a combination of the remaining channels of the multi-channel signal;a second parameter (CLD1) having energy information for a combination of the LF and RF channel and the center channel (C);a third parameter (CLD2) having energy information for the LS and the RS channel; anda fourth CLD parameter (CLD3) having energy information for the LF and the RF channel.

7. Parameter calculator in accordance with claim 6, in which the parameter recalculator is operative to derive the upmix CLD parameter according to the following formula:

8. Parameter calculator in accordance with claim 5, in which the parameter recalculator is operative to derive the ICC parameter using: a first CLD parameter (CLD0) having energy information for a combination of the LF and LR channel and a combination of the remaining channels of the multi-channel signal:a second parameter (CLD1) having energy information for a combination of the LF and RF channel and the center channel (C):a third parameter (CLD2) having energy information for the LS and the RS channel; anda fourth CLD parameter (CLD3) having energy information for the LF and the RF channel;a first ICC parameter (ICC2) having information on a correlation between the LS and the RS channel; anda second ICC parameter (ICC3) having information on a correlation between the LF and the RF channel.

9. Parameter calculator in accordance with claim 8, in which the ICC parameter is derived according to the following formula:

10. Parameter calculator in accordance with claim 5, in which the parameter recalculator is operative to derive the CLD parameter using: a first CLD parameter CLD0 having energy information for the center channel (C) and a combination of the other channels of the multi-channel signal;a second CLD parameter (CLD1) having energy information for a combination of the LF and LS channel and a combination of the RF and RS channel;an ICC parameter (ICC0) having correlation information between the center channel (C) and a combination of the other channels of the multi-channel signal.

11. Parameter calculator in accordance with claim 10, in which the CLD parameter is derived from the following formula:

12. Parameter calculator in accordance with claim 5, in which the parameter recalculator is operative to derive the ICC parameter using: a first CLD parameter CLD0 having energy information for the center channel (C) and a combination of the other channels of the multi-channel signal;a second CLD parameter (CLD1) having energy information for a combination of the LF and LS channel and a combination of the RF and RS channel;a first ICC parameter (ICC0) having correlation information between the center channel (C) and a combination of the other channels of the multi-channel signal; anda second ICC parameter (ICC1) having correlation information between a combination of the LF and the LS channel and a combination of the RF and RS channel.

13. Parameter calculator in accordance with claim 12, in which the parameter recalculator is operative to derive the ICC value using the following formula:

14. Parameter calculator in accordance with claim 1, in which the parameter recalculator is operative to use multi-channel parameters describing a subband representation of the multi-channel signal.

15. Parameter calculator in accordance with claim 1, in which the parameter recalculator is operative to use complex valued multi-channel parameters.

16. Channel reconstructor having a parameter reconstructor, comprising: a parameter calculator in accordance with claim 1; andan upmixer for deriving the intermediate channel representation using the upmix parameters and the downmix signal.

17. Method for generating upmix parameters for upmixing a downmix signal into an intermediate channel representation of a multi-channel signal having more channels than the downmix signal and less channels than the multi-channel signal, the downmix signal having associated thereto multi-channel parameters describing spatial properties of the multi-channel signal, wherein the multi-channel signal includes channels not included in the intermediate channel representation and wherein the multi-channel parameters include information on the channels not included in the intermediate channel representation, the method comprising: deriving the upmix parameters from the multi-channel parameters using the parameters having information on channels not included in the intermediate channel representation.

18. Audio receiver or audio player, the receiver or audio player having a parameter calculator for deriving upmix parameters for upmixing a downmix signal into an intermediate channel representation of a multi-channel signal having more channels than the downmix signal and less channels than the multi-channel signal, the downmix signal having associated thereto multi-channel parameters describing spatial properties of the multi-channel signal, wherein the multi-channel signal includes channels not included in the intermediate channel representation and wherein the multi-channel parameters include information on the channels not included in the intermediate channel representation, the parameter calculator comprising: a parameter recalculator for deriving the upmix parameters from the multi-channel parameters using the parameters having information on channels not included in the intermediate channel representation.

19. Method of receiving or audio playing, the method having a method for generating upmix parameters for upmixing a downmix signal into an intermediate channel representation of a multi-channel signal having more channels than the downmix signal and less channels than the multi-channel signal, the downmix signal having associated thereto multi-channel parameters describing spatial properties of the multi-channel signal, wherein the multi-channel signal includes channels not included in the intermediate channel representation and wherein the multi-channel parameters include information on the channels not included in the intermediate channel representation, the method comprising: deriving the upmix parameters from the multi-channel parameters using the parameters having information on channels not included in the intermediate channel representation.

20. Computer program having a program code for performing, when running on a computer, a method for generating upmix parameters for upmixing a downmix signal into an intermediate channel representation of a multi-channel signal having more channels than the downmix signal and less channels than the multi-channel signal, the downmix signal having associated thereto multi-channel parameters describing spatial properties of the multi-channel signal, wherein the multi-channel signal includes channels not included in the intermediate channel representation and wherein the multi-channel parameters include information on the channels not included in the intermediate channel representation, the method comprising: deriving the upmix parameters from the multi-channel parameters using the parameters having information on channels not included in the intermediate channel representation.

21. Computer program having a program code for performing, when running on a computer, a method for receiving or audio playing, the method having a method for generating upmix parameters for upmixing a downmix signal into an intermediate channel representation of a multi-channel signal having more channels than the downmix signal and less channels than the multi-channel signal, the downmix signal having associated thereto multi-channel parameters describing spatial properties of the multi-channel signal, wherein the multi-channel signal includes channels not included in the intermediate channel representation and wherein the multi-channel parameters include information on the channels not included in the intermediate channel representation, the method comprising: deriving the upmix parameters from the multi-channel parameters using the parameters having information on channels not included in the intermediate channel representation.