Apparatus and method for generating a level parameter and apparatus and method for generating a multi-channel representation

• US 20070002971A1
• Filed: 09/08/2006
• Published: 01/04/2007
• Est. Priority Date: 04/16/2004
• Status: Active Grant

• Current Assignee: Dolby International AB (Dolby Laboratories Incorporated)
• Original Assignee: Dolby International AB (Dolby Laboratories Incorporated)
• Inventors: Roeden, Jonas, Kjoerling, Kristofer, Engdegard, Jonas, Purnhagen, Heiko, Villemoes, Lars
• Granted Patent: US 8,223,976 B2
• Time in Patent Office: Days
• US Class Current: 375/316
• CPC Class Codes: G10L 19/008 Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
• CPC Class Codes: G10L 19/0204 using subband decomposition
• CPC Class Codes: G10L 19/032 Quantisation or dequantisation of spectral components
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: G10L 19/26 Pre-filtering or post-filtering
• CPC Class Codes: H04R 5/00 Stereophonic arrangements stereophonic pick-ups H04R9/16, H04R11/12, H04R17/08, H04R19/10
• CPC Class Codes: H04S 2400/01 Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved
• CPC Class Codes: H04S 2400/03 Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1 H04S2400/01 takes precedence
• CPC Class Codes: H04S 2420/03 Application of parametric coding in stereophonic audio systems
• CPC Class Codes: H04S 3/02 of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other
• CPC Class Codes: H04S 5/00 Pseudo-stereo systems, e.g. in which additional channel signals are derived from monophonic signals by means of phase shifting, time delay or reverberation

Abstract

A parameter representation of a multi-channel signal having several original channels includes a parameter set, which, when used together with at least one down-mix channel allows a multi-channel reconstruction. An additional level parameter is calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels. The additional level parameter is transmitted to a multi-channel reconstructor together with the parameter set or together with a down-mix channel. An apparatus for generating a multi-channel representation uses the level parameter to correct the energy of the at least one transmitted down-mix channel before entering the down-mix signal into an up-mixer or within the up-mixing process.

Claims

1. Apparatus for generating a level parameter within a parameter representation of a multi-channel signal having several original channels, the parameter representation comprising a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, the apparatus comprising:

a level parameter calculator for calculating a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels; and

an output interface for generating output data including the level parameter and the parameter set or the level parameter and the at least one down-mix channel.

2. Apparatus in accordance with claim 1, in which the level parameter calculator is operative to calculate, as the level parameter, a measure of a ratio between a sum of energies of the original channels and an energy of the at least one down-mix channel.

3. Apparatus in accordance with claim 1, in which the parameter representation includes a parameter set for each one of a number of frequency bands of the at least one down-mix channels, and

in which the parameter calculator is operative to calculate a level parameter for each one of the frequency bands.

4. Apparatus in accordance with claim 1, in which the parameter representation includes a parameter set for a time period in a sequence of time periods of the at least one down-mix channel, and

in which the level parameter calculator is operative to calculate a level parameter for each time period in a sequence of time periods of the at least one down-mix channel.

5. Apparatus in accordance with claim 1, in which the output interface is operative to generate a scalable data stream, which includes, in a lower scaling layer, a first subgroup of parameters of the parameter set, which allows a reconstruction of the first subgroup of output channels,

which includes, in a higher scaling layer, a second subgroup of parameters of the parameter set, which allow, together with the first subgroup, a reconstruction of a second subgroup of output channels, and

in which the output interface is further operative to enter the level parameter into the lower scaling layer.

6. Apparatus in accordance with claim 1, further comprising a parameter generator being formed to generate, as a first balance parameter, a left/right balance parameter, as a second balance parameter, a center balance parameter, as a third balance parameter, a front/back balance parameter, as a fourth balance parameter, a rear-left/right balance parameter, and as a fifth balance parameter, a low-frequency enhancement balance parameter.

7. Apparatus for generating a reconstructed multi-channel representation of an original multi-channel signal having at least three original channels using a parameter representation having a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, the parameter representation including a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels, the apparatus comprising:

a level corrector for applying a level correction of the at least one down-mix channel using the level parameter so that a corrected multi-channel reconstruction by up-mixing using parameters in the parameter set is obtainable.

8. Apparatus in accordance with claim 7, in which the level parameter is a ratio between energies of channels, and in which the level corrector is operative to weight the at least one down-mix channel using the level parameter.

9. Method of generating a level parameter within a parameter representation of a multi-channel signal having several original channels, the parameter representation comprising a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, comprising:

calculating a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels; and

generating output data including the level parameter and the parameter set or the level parameter and the at least one down-mix channel.

10. Method of generating a reconstructed multi-channel representation of an original multi-channel signal having at least three original channels using a parameter representation having a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, the parameter representation including a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels, the method comprising:

applying a level correction of the at least one down-mix channel using the level parameter so that a corrected multi-channel reconstruction by up-mixing using parameters in the parameter set is obtained.

11. Computer program having machine-readable instructions for performing a method of generating a level parameter within a parameter representation of a multi-channel signal having several original channels, the parameter representation comprising a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, the method comprising:

calculating a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels; and

generating output data including the level parameter and the parameter set or the level parameter and the at least one down-mix channel,

when running on a computer.

12. Computer program having machine-readable instructions for performing a method of generating a reconstructed multi-channel representation of an original multi-channel signal having at least three original channels using a parameter representation having a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, the parameter representation including a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels, the method comprising:

applying a level correction of the at least one down-mix channel using the level parameter so that a corrected multi-channel reconstruction by up-mixing using parameters in the parameter set is obtained,

when running on a computer.

13. Parameter representation having a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, the parameter representation including a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels.

14. Parameter representation in accordance with claim 13 for controlling a multi-channel reconstruction when input into an apparatus for generating a reconstructed multi-channel representation of an original multi-channel signal having at least three original channels using a parameter representation having a parameter set, which, when used together with at least one down-mix channel, allows a multi-channel reconstruction, the parameter representation including a level parameter, the level parameter being calculated such that an energy of the at least one downmix channel weighted by the level parameter is equal to a sum of energies of the original channels, the apparatus comprising:

a level corrector for applying a level correction of the at least one down-mix channel using the level parameter so that a corrected multi-channel reconstruction by up-mixing using parameters in the parameter set is obtainable.