Apparatus and method for generating an output signal employing a decomposer

Patent metadata

Field	Value
Publication number	US-9729991-B2
Application number	US-201314077062-A
Country	US
Kind code	B2
Filing date	Nov 11, 2013
Priority date	May 11, 2011
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

An apparatus for generating an output signal having at least two output channels from an input signal having at least two input channels, has an ambient/direct decomposer, an ambient modification unit and a combination unit. The ambient/direct decomposer is adapted to decompose at least two input channels of the input signal such that each one of the at least two input channels is decomposed into a signal of a first signal group and into a signal of a second signal group. The ambient modification unit is adapted to modify a signal of the ambient signal group or a signal derived from a signal of the ambient signal group to obtain a modified signal as a first output channel. The combination unit is adapted to combine a signal of the ambient signal group or a signal derived from a signal of the ambient signal group and a signal of the direct signal group or a signal derived from a signal of the direct signal group as a second output channel.

First claim

The invention claimed is:

1. An apparatus for generating an output signal comprising at least two output channels from an input signal comprising at least two input channels, comprising:
an ambient/direct decomposer being adapted to decompose at least two input channels of the input signal such that each one of the at least two input channels is decomposed into an ambient signal of an ambient signal group and into a direct signal of a direct signal group;
an ambient modification unit being adapted to modify an ambient signal of the ambient signal group or a signal derived from a signal of the ambient signal group to acquire a modified ambient signal as a first output channel for a first loudspeaker of a plurality of loudspeakers; and
a combination unit being adapted to combine an ambient signal of the ambient signal group or a signal derived from an ambient signal of the ambient signal group and a direct signal of the direct signal group or a signal derived from a direct signal of the direct signal group as a second output channel for a second loudspeaker of the plurality of loudspeakers,
wherein the apparatus is adapted via a function only a first amount of ambient signal portions of one of the at least two input channels to one of the plurality of loudspeakers, and wherein the apparatus is adapted via a function a remaining amount of the ambient signal portions of said one of the at least two input channels plus the direct signal portions of said one of the at least two input channels to another one of the plurality of loudspeakers.

2. The apparatus according to claim 1 , wherein the ambient modification unit is adapted to modify a first derived signal, wherein the first derived signal is derived by filtering, gain modifying or decorrelating an ambient signal of the ambient signal group,
wherein the combination unit is adapted to modify a second derived signal, wherein the second derived signal is derived by filtering, gain modifying or decorrelating an ambient signal of the ambient signal group, and
wherein the combination unit is adapted to modify a third derived signal, wherein the third derived signal is derived by filtering, gain modifying or decorrelating the direct signal of the direct signal group.

3. The apparatus according to claim 1 , wherein the ambient modification unit is adapted to combine a first ambient signal of the ambient signal group and a second ambient signal of the ambient signal group to acquire a modified ambient signal.

4. The apparatus according to claim 1 , wherein the apparatus further comprises a first ambient gain modifier being adapted to gain modify an ambient signal of the ambient signal group or a signal derived from an ambient signal of the ambient signal group to acquire a first gain modified ambient signal; and
wherein the combination unit is adapted to combine the first gain modified ambient signal and a direct signal of the direct signal group or a signal derived from a direct signal of the direct signal group as the second output channel.

5. The apparatus according to claim 4 , wherein the gain modifier is adapted to gain modify an ambient signal of the ambient signal group such that at a first point in time, the ambient signal is gain modified with a first gain modification factor while at a different second point in time, the ambient signal is gain modified with a different second gain modification factor.

6. The apparatus according to claim 1 , wherein the ambient modification unit comprises a decorrelator to decorrelate a first ambient signal of the ambient signal group or a signal derived from an ambient signal of the ambient signal group to acquire the modified signal as the first output channel.

7. The apparatus according to claim 1 , wherein the modification unit comprises a second ambient gain modifier being adapted to gain modify an ambient signal of the ambient signal group or a signal derived from an ambient signal of the ambient signal group to acquire the modified signal as the first output channel.

8. The apparatus according to claim 1 , wherein the ambient modification unit comprises a filter unit to filter an ambient signal of the ambient signal group or a signal derived from an ambient signal of the ambient signal group to acquire the modified signal as the first output channel.

9. The apparatus according to claim 8 , wherein the filter unit is adapted to employ a low pass filter.

10. The apparatus according to claim 1 , wherein the combination unit is adapted to form a linear combination of an ambient signal of the ambient signal group or a signal derived from an ambient signal of the ambient signal group and a direct signal of the direct signal group or a signal derived from a direct signal of the direct signal group to generate the combination signal.

11. The apparatus according to claim 1 ,
wherein the ambient/direct decomposer is adapted to decompose at least three input channels of the input signal,
wherein the ambient/direct decomposer comprises a downmixer, an analyzer and a signal processor,
wherein the downmixer is adapted to downmix the input signal to acquire a downmix signal, wherein the downmixer is configured for downmixing so that a number of downmix channels of the downmixed signal is at least 2 and smaller than the number of input channels;
wherein the analyzer is adapted to analyze the downmixed signal to derive an analysis result; and
wherein the signal processor is adapted to process the input signal or a signal derived from the input signal, or a signal, from which the input signal is derived, using the analysis result, wherein the signal processor is configured for applying the analysis result to the input channels of the input signal or channels of the signal derived from the input signal to acquire the decomposed signal.

12. The apparatus according to claim 11 , further comprising a time/frequency converter for converting the input channels into a time sequence of channel frequency representations, each input channel frequency representation comprising a plurality of subbands, or in which the downmixer comprises a time/frequency converter for converting the downmixed signal,
wherein the analyzer is configured for generating an analysis result for individual subbands, and
wherein the signal processor is configured for applying the individual analysis results to corresponding subbands of the input signal or the signal derived from the input signal.

13. The apparatus according to claim 11 ,
wherein the analyzer is configured to produce, as the analysis result, weighting factors, and
wherein the signal processor is configured for applying the weighting factors to the input signal or the signal derived from the input signal by weighting with the weighting factors.

14. The apparatus according to claim 11 , wherein the analyzer is configured for using a pre-stored frequency-dependent reference curve indicating a similarity between two signals generatable by previously known reference signals.

15. A method for generating an output signal comprising at least two output channels from an input signal comprising at least two input channels, comprising:
decomposing at least two input channels of the input signal such that each one of the at least two input channels is decomposed into an ambient signal of an ambient group and into a direct signal of a direct signal group;
modifying an ambient signal of the ambient signal group or a signal derived from an ambient signal of the ambient signal group to acquire a modified signal as a first output channel;
combining an ambient signal of the ambient signal group or a signal derived from an

Assignees

• Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E V

Inventors

• Walther Andreas
• Silzle Andreas
• Hellmuth Oliver
• Grill Bernhard
• Popp Harald

Classifications

• H04S3/008 Primary

  in which the audio signals are in digital form, i.e. employing more than two discrete digital channels (data reduction aspects thereof based on psychoacoustics G10L19/02) · CPC title

• H04S3/006 Primary

  in which a plurality of audio signals are transformed in a combination of audio signals and modulated signals, e.g. CD-4 systems · CPC title

• H04S3/00 Primary

  Systems employing more than two channels, e.g. quadraphonic (H04S5/00, H04S7/00 take precedence) · CPC title