METHOD AND APPARATUS FOR ENHANCEMENT OF AUDIO RECONSTRUCTION

• US 20100169103A1
• Filed: 02/01/2008
• Published: 07/01/2010
• Est. Priority Date: 03/21/2007
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: Pulkki, Ville
• Granted Patent: US 9,015,051 B2
• Time in Patent Office: Days
• US Class Current: 704/500
• CPC Class Codes: H04R 27/00 Public address systems circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; monitoring or testing arrangements for public address systems H04R29/007; amplifiers H03F
• CPC Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• CPC Class Codes: H04S 2400/13 Aspects of volume control, not necessarily automatic, in stereophonic sound systems
• CPC Class Codes: H04S 2420/07 Synergistic effects of band splitting and sub-band processing
• CPC Class Codes: H04S 2420/11 Application of ambisonics in stereophonic audio systems
• CPC Class Codes: H04S 7/302 Electronic adaptation of stereophonic sound system to listener position or orientation H04S7/301 takes precedence
• CPC Class Codes: H04S 7/305 Electronic adaptation of stereophonic audio signals to reverberation of the listening space H04S7/301 takes precedence

Abstract

An audio signal having at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position is reconstructed to derive a reconstructed audio signal. A desired direction of origin with respect to the recording position is selected. The portion of the audio channel is modified for deriving a reconstructed portion of the reconstructed audio signal, wherein the modifying includes increasing an intensity of the portion of the audio channel having direction parameters indicating a direction of origin close to the desired direction of origin with respect to another portion of the audio channel having direction parameters indicating a direction of origin further away from the desired direction of origin.

Claims

1. A method for reconstructing an audio signal comprising at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position, the method comprising:

selecting a set direction of origin with respect to the recording position; and

modifying the portion of the audio channel for deriving a reconstructed portion of the reconstructed audio signal, wherein the modification comprises increasing an intensity of the portion of the audio channel comprising direction parameters indicating a direction of origin close to the set direction of origin with respect to another portion of the audio channel comprising direction parameters indicating a direction of origin further away from the set direction of origin.

2. The method of claim 1, wherein selecting comprises:

reading the set direction from a memory.

3. The method of claim 1, in which the modification comprises modifying a frequency domain representation of the portion of the audio channel.

4. The method of claim 1, in which the modification comprises modifying a time domain representation of the portion of the audio channel.

5. The method of claim 1, in which the modification comprises deriving a scaling factor for each portion of the audio channel such that a scaled portion of the audio channel, the scaled portion derived by multiplying the portion of the audio channel with the scaling factor, comprising associated direction parameters indicating a direction of origin close to the desired direction of origin comprises an increased intensity with respect to another scaled portion of the audio channel comprising associated direction parameters indicating a direction of origin further away from the desired direction of origin

6. The method of claim 1, further comprising:

deriving a frequency representation of the at least one audio channel.

7. The method of claim 6, in which the deriving comprises deriving a representation of a first and a second finite width frequency interval of the at least one audio channel, wherein the width of the first frequency interval is different than the width of the second frequency interval.

8. The method of claim 1, wherein selecting of the desired direction of origin comprises receiving input parameters indicating the desired direction as a user input.

9. The method of claim 1, wherein selecting the desired direction comprises receiving direction parameters associated to the audio signal, the direction parameters indicating the desired direction.

10. The method of claim 1, wherein selecting the desired direction comprises determining the direction of origin of a finite width frequency interval of the at least one audio channel.

11. The method of claim 1, further comprising:

receiving a diffuseness parameter associated to the audio channel, the diffuseness parameter indicating a diffuseness of the portion of the audio channel; and

wherein the modifying of the portion of the audio channel comprises decreasing an intensity of the portion of the audio channel comprising a diffuseness parameter indicating a high diffuseness with respect to another portion of the audio channel comprising a diffuseness parameter indicating a lower diffuseness.

12. The method of claim 1, further comprising:

up-mixing the at least one audio channel to multiple channels for playback via a loudspeaker system comprising multiple loudspeakers, wherein each of the multiple channels comprises a channel portion corresponding to the portion of the at least one audio channel.

13. The method of claim 12, in which the modification comprises increasing the intensity of each of the channel portions up-mixed from the portion of the audio channel comprising direction parameters indicating a direction of origin close to the desired direction of origin with respect to other channel portions of the multiple channels up-mixed from another portion of the audio channel comprising direction parameters indicating a direction of origin further away from the desired direction of origin.

14. The method of claim 13, further comprising:

panning the amplitude of the channel portions such that a perceived direction of origin of reconstructed channel portions corresponds to the direction of origin when played back using a predetermined loudspeaker set-up.

15. The method for enhancing a directional perception of an audio signal, the method comprising:

deriving at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position;

selecting a set direction of origin with respect to the recording position; and

modifying a portion of the audio channel for deriving a portion of an enhanced audio signal, wherein the modification comprises increasing an intensity of a portion of the audio channel comprising direction parameters indicating a direction of origin close to the set direction of origin with respect to another portion of the audio channel comprising direction parameters indicating a direction of origin further away from the set direction of origin.

16. An audio decoder for reconstructing an audio signal comprising at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position, comprising:

a direction selector adapted to select a set direction of origin with respect to the recording position; and

an audio portion modifier for modifying the portion of the audio channel for deriving a reconstructed portion of the reconstructed audio signal, wherein the modification comprises increasing an intensity of the portion of the audio channel comprising direction parameters indicating a direction of origin close to the set direction of origin with respect to another portion of the audio channel comprising direction parameters indicating a direction of origin further away from the set direction of origin.

17. An audio encoder for enhancing a directional perception of an audio signal, the audio encoder comprising:

a signal generator for deriving at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position;

a direction selector adapted to select a set direction of origin with respect to the recording position; and

a signal modifier for modifying the portion of the audio channel for deriving a portion of an enhanced audio signal, wherein the modification comprises increasing an intensity of a portion of the audio channel comprising direction parameters indicating a direction of origin close to a set direction of origin with respect to another portion of the audio channel comprising direction parameters indicating a direction of origin further away from the set direction of origin.

18. A system for enhancement of a reconstructed audio signal, the system comprising:

an audio encoder for deriving an audio signal comprising at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position;

a direction selector adapted to select a set direction of origin with respect to the recording position; and

an audio decoder comprising an audio portion modifier for modifying the portion of the audio channel for deriving a reconstructed portion of the reconstructed audio signal, wherein the modifying comprises increasing an intensity of the portion of the audio channel comprising direction parameters indicating a direction of origin close to a set direction of origin with respect to another portion of the audio channel comprising direction parameters indicating a direction of origin further away from the set direction of origin.

19. A computer program for, when running on a computer, implementing a method for reconstructing an audio signal comprising at least one audio channel and associated direction parameters indicating a direction of origin of a portion of the audio channel with respect to a recording position, the method comprising:

selecting a set direction of origin with respect to the recording position; and

modifying the portion of the audio channel for deriving a reconstructed portion of the reconstructed audio signal, wherein the modification comprises increasing an intensity of the portion of the audio channel comprising direction parameters indicating a direction of origin close to the set direction of origin with respect to another portion of the audio channel comprising direction parameters indicating a direction of origin further away from the set direction of origin.