Apparatus and method for generating a synthesis audio signal and for encoding an audio signal

Patent metadata

Field	Value
Publication number	US-9076433-B2
Application number	US-201213687678-A
Country	US
Kind code	B2
Filing date	Nov 28, 2012
Priority date	Apr 9, 2009
Publication date	Jul 7, 2015
Grant date	Jul 7, 2015

Abstract

An apparatus for generating a synthesis audio signal using a patching control signal has a first converter, a spectral domain patch generator, a high frequency reconstruction manipulator and a combiner. The first converter is configured for converting a time portion of an audio signal into a spectral representation. The spectral domain patch generator is configured for performing a plurality of different spectral domain patching algorithms, wherein each patching algorithm generates a modified spectral representation having spectral components in an upper frequency band derived from corresponding spectral components in a core frequency band of the audio signal. The spectral domain patch generator is furthermore configured to select a first spectral domain patching algorithm from the plurality of patching algorithms for a first time portion and a second spectral domain patching algorithm from the plurality of patching algorithm for a second different time portion in accordance with the patching control signal to obtain the modified spectral representation.

First claim

The invention claimed is:

1. An apparatus for generating a synthesis audio signal using a patching control signal, the apparatus comprising:
a first converter for converting a time portion of an audio signal into a spectral representation;
a spectral domain patch generator for performing a plurality of different spectral domain patching algorithms, wherein each patching algorithm generates a modified spectral representation comprising spectral components in an upper frequency band derived from corresponding spectral components in a core frequency band of the audio signal, and wherein the spectral domain patch generator is configured to select a first spectral domain patching algorithm from the plurality of patching algorithms for a first time portion and a second spectral domain patching algorithm from the plurality of patching algorithms for a second different time portion in accordance with the patching control signal to achieve the modified spectral representation;
a high frequency reconstruction manipulator for manipulating the modified spectral representation or a signal derived from the modified spectral representation in accordance with a spectral band replication parameter to achieve a bandwidth extended signal; and
a combiner for combining the audio signal comprising spectral components in the core frequency band or a signal derived from the audio signal with the bandwidth extended signal to achieve the synthesis audio signal,
wherein the spectral domain patch generator is configured for performing at least two different spectral domain patching algorithms from a group of patching algorithms in the spectral domain, the group of patching algorithms comprising a first patching algorithm comprising a harmonic transposition based on a single phase vocoder and non-harmonic copying-up spectral band replication functionalities, a second patching algorithm comprising a harmonic transposition based on a multiple phase vocoder, a third patching algorithm comprising non-harmonic copying-up spectral band replication functionalities and a fourth patching algorithm comprising a non-linear distortion, and
wherein at least one of the first converter, the spectral domain patch generator, the high frequency reconstruction manipulator and the combiner comprises a hardware implementation.

2. The apparatus in accordance with claim 1 , in which the spectral domain patch generator is implemented to be operative in a spectral domain and not in a time domain.

3. The apparatus in accordance with claim 1 , wherein the spectral domain patch generator is configured for performing a selected patching algorithm from the at least two different spectral domain patching algorithms, the selected patching algorithm comprising the first patching algorithm, the first patching algorithm comprising a harmonic transposition based on a single phase vocoder comprising a bandwidth extension factor of two controlling a transform from a source frequency band extracted from the core frequency band into a first target frequency band, wherein phases of the spectral components in the source frequency band are multiplied by the bandwidth extension factor such that the first target frequency band comprises frequencies ranging from the crossover frequency to twice the crossover frequency, the first patching algorithm further comprising non-harmonic copying-up spectral band replication functionalities for transforming spectral components in the first target frequency band into a second target frequency band by a first copying-up such that the second target frequency band comprises frequencies ranging from twice the crossover frequency to three times the crossover frequency and for further transforming spectral components in the second target frequency band into a third target frequency band by a second copying-up such that the third target frequency band comprises frequencies ranging from three times the crossover frequency to four times the crossover frequency comprised in the upper frequency band, the upper frequency band comprising the first, second and third target frequency band.

4. The apparatus in accordance with claim 1 , wherein the spectral domain patch generator is configured for performing a selected patching algorithm from the at least two different spectral domain patching algorithms, the selected patching algorithm comprising the second patching algorithm, the second patching algorithm comprising a harmonic transposition based on a multiple phase vocoder comprising a first bandwidth extension factor of two controlling a transform from a first frequency band extracted from the core frequency band into a first target frequency band, wherein phases of the spectral components in the first source frequency band are multiplied by the first bandwidth extension factor such that the first target frequency band comprises frequencies ranging from the crossover frequency to twice the crossover frequency, the second patching algorithm further comprising a second bandwidth extension factor of three controlling a transform from a second source frequency band extracted from the core frequency band into a second target frequency band, wherein phases of the spectral components in the second source frequency band are multiplied by the second bandwidth extension factor such that the second target frequency band comprises frequencies ranging from twice the crossover frequency to three times the crossover frequency or ranging from the crossover frequency to three time the crossover frequency, the second patching algorithm further comprising a third bandwidth extension factor of four controlling a transform from a third source frequency band extracted from the core frequency band into a third target frequency band, wherein phases of the spectral components in the third source frequency band are multiplied by the third bandwidth extension factor such that the third target frequency band comprises frequencies ranging from three times the crossover frequency to four times the crossover frequency or ranging from the crossover frequency to four times the crossover frequency comprised in the upper frequency band, the upper frequency comprising the first, second and third target frequency band.

5. The apparatus in accordance with claim 1 , wherein the spectral domain patch generator is configured for performing a selected patching algorithm from the at least two different spectral domain patching algorithms, the selected patching algorithm comprising the third patching algorithm, the third patching algorithm comprising non-harmonic copying-up spectral band replication functionalities for transforming spectral components in a source frequency band being the core frequency band into a first target frequency band by a first copying-up such that the first target frequency band comprises frequencies ranging from the crossover frequency to twice the crossover frequency, for further transforming spectral components in the first target frequency band into a second target frequency band by a second copying-up such that the second target frequency band comprises frequencies ranging from twice the crossover frequency to three times the crossover frequency and for further transforming spectral components in the second target frequency band into a third target frequency band by a third copying-up such that the third target frequency band comprises frequencies ranging from three times the crossover frequency to four times the crossover frequency comprised in the upper frequency band, the upper frequency band comprising the first, second and third target frequency band.

6. The apparatus in accordance with claim 1 , wherein the spectral domain patch generator is configured for performing a selected patching algorithm from the at least two different spectral domain patching algorithms, the sele

Assignees

• Fraunhofer Ges Forschung
• Fraunhofer Ges Forschung

Inventors

• Nagel Frederik
• Multrus Markus
• Lecomte Jeremie
• Bayer Stefan
• Fuchs Guillaume
• Hilpert Johannes
• Robilliard Julien

Classifications

• G10L19/18 Primary

  Vocoders using multiple modes · CPC title

• G10L19/008 Primary

  Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing · CPC title

• G10L21/038

  using band spreading techniques · CPC title

• G10L19/02

  using spectral analysis, e.g. transform vocoders or subband vocoders · CPC title

• G10L21/04 Primary

  Time compression or expansion · CPC title