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Improved transform coding of speech and audio signals

An audio signal, transform coding technology, applied in the field of signal processing, can solve the problem of not very reliable, high complexity and so on

Active Publication Date: 2012-05-30
TELEFON AB LM ERICSSON (PUBL)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Also, wideband audio coders usually use high-complexity auditory (psychoacoustic) models, which are not very reliable at low bitrates (below 64kbps)

Method used

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  • Improved transform coding of speech and audio signals
  • Improved transform coding of speech and audio signals
  • Improved transform coding of speech and audio signals

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Embodiment Construction

[0032] The present invention mainly relates to transform coding, and in particular to subband coding.

[0033] In order to simplify the understanding of the following description of the embodiments of the present invention, some key definitions will be described below.

[0034] Signal processing in telecommunications sometimes utilizes "companding" as a way to improve signal representation with limited dynamic range. The term is a combination of compression and expansion, thereby indicating that the dynamic range of the signal is compressed before transmission and expanded to the original value at the receiver. This allows a signal with a large dynamic range to be transmitted through a facility with a smaller dynamic range capability.

[0035] In the following, the invention will be described with respect to a specific exemplary and non-limiting codec implementation suitable for the ITU-T G.722.1 full-band codec extension (now renamed ITU-T G.719). In this particular example...

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PUM

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Abstract

In a method of perceptual transform coding of audio signals in a telecommunication system, performing the steps of determining transform coefficients representative of a time to frequency transformation of a time segmented input audio signal; determining a spectrum of perceptual sub-bands for said input audio signal based on said determined transform coefficients; determining masking thresholds for each said sub-band based on said determined spectrum; computing scale factors for each said sub-band based on said determined masking thresholds, and finally adapting said computed scale factors for each said sub-band to prevent energy loss for perceptually relevant sub-bands.

Description

technical field [0001] The present invention relates generally to signal processing such as signal compression and audio coding, and more particularly to improved transform speech and audio coding and corresponding devices. Background technique [0002] An encoder is a device, circuit, or computer program that analyzes a signal, such as an audio signal, and outputs the signal in encoded form. The resulting signal is typically used for transmission, storage and / or encryption purposes. A decoder, on the other hand, is a device, circuit, or computer program that reverses the operation of an encoder in that it receives an encoded signal and outputs a decoded signal. [0003] In most prior art encoders, such as audio encoders, each frame of the input signal is analyzed and transformed from the time domain to the frequency domain. The results of this analysis are quantized and coded, and then transmitted or stored depending on the application. On the receiving side (or when usi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G10L19/02H04B1/66
CPCG10L19/0212G10L19/035G10L19/0204
Inventor M·布赖恩德A·塔莱布
Owner TELEFON AB LM ERICSSON (PUBL)