Apparatus and method for generating an enhanced signal using independent noise-filling

Patent metadata

Field	Value
Publication number	US-10354663-B2
Application number	US-201615353292-A
Country	US
Kind code	B2
Filing date	Nov 16, 2016
Priority date	Jul 28, 2014
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

An apparatus for generating an enhanced signal from an input signal, wherein the enhanced signal has spectral values for an enhancement spectral region, the spectral values for the enhancement spectral regions not being contained in the input signal, includes a mapper for mapping a source spectral region of the input signal to a target region in the enhancement spectral region, the source spectral region including a noise-filling region; and a noise filler configured for generating first noise values for the noise-filling region in the source spectral region of the input signal and for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from the first noise values or for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from first noise values in the source region.

First claim

The invention claimed is:

1. An audio decoder for generating an enhanced audio signal from an input audio signal, wherein the enhanced audio signal comprises spectral values for an enhancement spectral region, the spectral values for the enhancement spectral regions not being comprised in the input audio signal, comprising:
a mapper configured for mapping a source spectral region of the input audio signal to a target region in the enhancement spectral region, the source spectral region comprising a noise-filling region; and
a noise filler configured for generating first noise values for the noise-filling region in the source spectral region of the input audio signal and for generating second noise values for a noise region in the target region, wherein the second noise values are decorrelated from the first noise values,
wherein the noise filler is configured for:
identifying the noise-filling region comprising the first noise values in the input audio signal;
copying at least a region of the input audio signal to a source tile buffer, the region comprising the source spectral region; and
replacing the first noise values in the source tile buffer as identified by independent noise values; and
wherein the mapper is configured to map the source tile buffer comprising decorrelated noise values to the target region, and
wherein one or more of the mapper and the noise filler is implemented, at least in part, by one or more hardware elements of the audio decoder.

2. The audio decoder of claim 1 ,
wherein the input audio signal is an encoded signal comprising noise-filling parameters for the source spectral region of the input audio signal,
wherein the noise filler is configured for generating the first noise values using the noise-filling parameters and for generating the second noise values using an energy information on the first noise values.

3. The audio decoder of claim 1 ,
wherein the noise filler is configured to measure an energy information on the decorrelated noise values and an energy information on the first noise values and to scale the decorrelated noise values using a scaling value derived from the energy information on the decorrelated noise values and the energy information on the first noise values.

4. The audio decoder of claim 1 ,
wherein the noise filler is configured for generating the second noise values subsequent to an operation of the mapper or for generating the first and the second noise values subsequent to an operation of the mapper.

5. The audio decoder of claim 1 ,
wherein the mapper is configured to map the source region to the target region, and
wherein the noise filler is configured to perform noise-filling in spectral regions by generating the first noise values using noise-filling and noise-filling parameters transmitted in the input audio signal as side information, and to perform noise-filling in the target region to generate the second spectral values using energy information on the first noise values.

6. The audio decoder of claim 1 , further comprising:
an envelope adjuster configured for adjusting the second noise values in the enhancement spectral region using spectral envelope information comprised in the input audio signal as side information.

7. The audio decoder of claim 1 ,
wherein the noise filler is configured to only use side information of the input audio signal to identify spectral positions for noise-filling, or
wherein the noise filler is configured to analyze a time or spectral characteristic of the input audio signal with or without spectral values in the noise-filling region to identify spectral positions for noise-filling.

8. The audio decoder of claim 1 ,
wherein the noise filler is configured to identify noise positions using an identification vector comprising entries for spectral positions in the source spectral region only, or comprising entries for spectral positions in the source spectral region and in the target region.

9. The audio decoder of claim 1 ,
wherein the noise filler is configured to copy, in the copying operation, a complete spectral portion of the input audio signal or a complete spectral portion of the input audio signal above a noise-filling border frequency generally usable by the mapper to the source tile buffer and to perform the replacing operation on the full source tile buffer, or
wherein the noise filler is configured to copy, in the copying operation, only a spectral region of the input audio signal identified by one or more specific source identifiers for a source region to be used by the mapper for the target region, where an individual source tile buffer is used for each different individual mapping operation.

10. The audio decoder of claim 1 ,
wherein the mapper is configured to perform a gap filling operation for generating the target region, wherein the audio decoder further comprises:
a spectral domain audio decoder configured for generating a first decoded representation of a first set of first spectral portions, the first decoded representation comprising a first spectral resolution;
a parametric decoder configured for generating a second decoded representation of a second set of second spectral portions comprising a second spectral resolution being lower than the first spectral resolution;
a frequency regenerator configured for regenerating a reconstructed second spectral portion comprising the first spectral resolution using a first spectral portion and spectral envelope information for the reconstructed second spectral portion; and
a spectrum time converter configured for converting the first decoded representation and the reconstructed second spectral portion into a time representation,
wherein the mapper and the noise filler are at least partly comprised in the frequency regenerator.

11. The audio decoder of claim 10 ,
wherein the spectral domain audio decoder is configured to output a sequence of decoded frames of spectral values, a decoded frame being the first decoded representation, wherein the decoded frame comprises spectral values for the first set of first spectral portions and zero indications for the second set of second spectral portions,
wherein the audio decoder further comprises a combiner for combining spectral values generated by the frequency regenerator for the second set of second spectral portions and spectral values of the first set of first spectral portions in a reconstruction band to acquire a reconstructed spectral frame comprising spectral values for the first set of first spectral portions and the second set of second spectral portions; and
wherein the spectrum-time converter is configured to convert the reconstructed spectral frame into the time representation.

12. The audio decoder of claim 1 ,
further comprising:
for the target region, a source spectral region identification, and
wherein the mapper is configured for selecting the source spectral region using the source spectral region identification and for mapping the selected source spectral region to the target region.

13. A method of audio decoding for generating an enhanced audio signal from an input audio signal, wherein the enhanced audio signal comprises spectral values for an enhancement spectral region, the spectral values for the enhancement spectral regions not being comprised in the input audio signal, comprising:
mapping a source spectral region of the input audio signal to a target region in the enhancement spectral region, the source spectral region comprising a noise-filling region; and
generating first noise values for the noise-filling region in the source spectral region of the input audio signal and generating sec

Assignees

• Fraunhofer Ges Forschung

Inventors

• Disch Sascha
• Geiger Ralf
• Niedermeier Andreas
• Neusinger Matthias
• Schmidt Konstantin
• Wilde Stephan
• Schubert Benjamin
• Neukam Christian

Classifications

• G10L19/028 Primary

  Noise substitution, i.e. substituting non-tonal spectral components by noisy source (comfort noise for discontinuous speech transmission G10L19/012) · CPC title

• G10L15/20

  Speech recognition techniques specially adapted for robustness in adverse environments, e.g. in noise, of stress induced speech (G10L21/02 takes precedence) · CPC title

• G10L25/21

  the extracted parameters being power information · CPC title

• G10L21/038

  using band spreading techniques · CPC title

• G10L19/0204 Primary

  using subband decomposition · CPC title