Time warp activation signal provider, audio signal encoder, method for providing a time warp activation signal, method for encoding an audio signal and computer programs

• US 9,263,057 B2
• Filed: 11/11/2014
• Issued: 02/16/2016
• Est. Priority Date: 07/11/2008
• 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: Bayer, Stefan, Disch, Sascha, Geiger, Ralf, Fuchs, Guillaume, Neuendorf, Max, Schuller, Gerald, Edler, Bernd
• Primary Examiner(s): PULLIAS, JESSE SCOTT
• Application Number:
  US14/538,728
• Publication Number:
  US 20150066493A1
• Time in Patent Office: 462 Days
• Field of Search: 704200-257, 704500-504
• US Class Current: 1/1
• CPC Class Codes: G10L 19/002 Dynamic bit allocation for perceptual audio coders G10L19/032
• CPC Class Codes: G10L 19/022 Blocking, i.e. grouping of samples in time; Choice of analysis windows; Overlap factoring
• CPC Class Codes: G10L 19/025 Detection of transients or attacks for time/frequency resolution switching
• CPC Class Codes: G10L 19/028 Noise substitution, i.e. substituting non-tonal spectral components by noisy source comfort noise for discontinuous speech transmission G10L19/012
• CPC Class Codes: G10L 19/032 Quantisation or dequantisation of spectral components
• CPC Class Codes: G10L 19/265 Pre-filtering, e.g. high frequency emphasis prior to encoding
• CPC Class Codes: G10L 21/04 Time compression or expansion
• CPC Class Codes: G10L 21/043 by changing speed
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

An audio encoder has a window function controller, a windower, a time warper with a final quality check functionality, a time/frequency converter, a TNS stage or a quantizer encoder, the window function controller, the time warper, the TNS stage or an additional noise filling analyzer are controlled by signal analysis results obtained by a time warp analyzer or a signal classifier. Furthermore, a decoder applies a noise filling operation using a manipulated noise filling estimate depending on a harmonic or speech characteristic of the audio signal.

Claims

1. A decoder for decoding an encoded audio signal comprising:

an input interface for processing the encoded audio signal to acquire a noise filling measure and encoded audio data;

a decoder/re-quantizer for generating re-quantized data;

a signal analyzer for retrieving information, whether a time frame of the audio data comprises harmonic or speech characteristic; and

a noise filler for generating noise filling audio data,

wherein the noise filler is configured to generate noise filling data in response to the noise filling measure and the harmonic or speech characteristic of the audio data; and

a processor for processing the re-quantized data and the noise filling audio data to acquire a decoded audio signal;

wherein the encoded audio signal comprises data indicating, whether the time frame of the audio data comprises a harmonic or speech characteristic, and

wherein the signal analyzer is configured for analyzing the encoded audio signal to retrieve a data indicating, whether the time frame of the audio data comprises a harmonic or speech characteristic;

wherein the data is an indication that the time portion has been subjected to a time warping processing, and

wherein the processor comprises a time dewarper for time dewarping an audio signal derived from noise filling data and re-quantized data.

2. Method for decoding an encoded audio signal, wherein the encoded audio signal comprises data indicating, whether the time frame of the audio data comprises a harmonic or speech characteristic, comprising:

processing the encoded audio signal to acquire a noise filling measure and encoded audio data;

analyzing the encoded audio signal to retrieve a data indicating, whether the time frame of the audio data comprises a harmonic or speech characteristic, wherein the data is an indication that the time portion has been subjected to a time warping processing;

generating re-quantized data;

retrieving information, whether a time frame of the audio data comprises harmonic or speech characteristic; and

generating noise filling audio data in response to the noise filling measure and the harmonic or speech characteristic of the audio data; and

processing the re-quantized data and the noise filling audio data to acquire a decoded audio signal wherein the processing comprises time dewarping an audio signal derived from noise filling data and re-quantized data.

3. A non-transitory computer-readable storage medium having program code stored thereon, wherein the program code, when executed by a computer, performs the method of claim 2.