Hierarchical coding of digital audio signals

A technology of digital audio and audio encoder, applied in speech analysis, instruments, etc., can solve the problems of difficult encoding, low complexity, and increased encoder complexity.

Active Publication Date: 2010-08-04
FRANCE TELECOM SA
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This type of approach has the disadvantage of increasing the complexity of the encoder very significantly, whereas PCM-type encoding is recognized as having low complexity
Moreover, since PCM coding noise is white noise and thus uncorrelated, coding of such noise is difficult to achieve because compression techniques are essentially based on extracting properties from correlations of the signal to be coded

Method used

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  • Hierarchical coding of digital audio signals
  • Hierarchical coding of digital audio signals
  • Hierarchical coding of digital audio signals

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Embodiment Construction

[0058] figure 2 An encoding / decoding system according to the invention is illustrated.

[0059] Encoder 23 includes a quantizer Q PCM 20, which is capable of quantizing an input signal S in order to obtain a quantization index I transmitted on a transmission channel 21 to a decoder 24 PCM frame.

[0060] In a particular embodiment, the encoder is of PCM encoder type and implements an encoding law such as A or mu type described in the G.711 standard.

[0061] Thus, the obtained quantized index frame is shown in 15 and is in accordance with the G.711 A or mu-law type frame.

[0062] Methods for implementing the A and mu coding laws are included in the G.711 standard. They consist in determining the final quantization index by a low-complexity simple operation avoiding the storage of large value tables.

[0063] Thus, the pseudocode shown in Appendix A-10 gives an example of implementing an A-law such as that described in the G.711 standard (with linear approximation by seg...

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Abstract

The invention relates to a method for the scalar quantisation-based coding of samples of a digital audio signal (S), said samples being coded over a pre-determined number of bits in order to obtain a binary frame of quantisation indices (IMIC). The samples are coded using an amplitude compression law and a pre-determined number of the least-significant bits is not taken into account in the binary frame of quantisation indices. The coding method includes a step comprising the saving (27) of at least part of the least-significant bits which are not taken into account in the binary frame of quantisation indices and the determination (28) of an enhancement stream (IEXT) containing at least one saved bit. The invention also relates to an associated decoding method including steps comprising the reception (29) of an enhancement stream (I'EXT) containing one or more extension bits and the concatenation (30) of the extension bits behind the bits originating from the binary frame in order to obtain a decoded audio signal. The invention further relates to the coder and decoder used to carry out said methods.

Description

technical field [0001] The present invention relates to a method for hierarchical coding of audio data, more particularly to a method for scalar quantization-based coding. [0002] The encoding is especially designed for transmission and / or for storage of digital signals such as audio frequency signals (speech, music or other). [0003] The invention relates more particularly to the encoding of waveforms, such as PCM (for "Pulse Code Modulation") encoding in which each input sample is encoded individually without prediction. Background technique [0004] The general principle of PCM encoding / decoding specified by the recommended standard UIT-T G.711 is described such as with reference to FIG. 1 . The input signal is assumed to be defined with a minimum bandwidth of [300-3400 Hz] and sampled at 8 kHz (in a format known as "linear PCM") with a resolution of 16 bits per sample. [0005] The PCM encoder 13 comprises a quantization module Q receiving at its input the input sign...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G10L19/14G10L19/24
CPCG10L19/24
Inventor 巴拉茨·科维西斯蒂法尼·拉戈特
Owner FRANCE TELECOM SA
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