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Down-mixing signal generating and reducing method and device

A signal and frequency domain signal technology, used in speech analysis, stereo systems, instruments, etc., can solve the problems of left and right channel inversion downmix performance, reduce the subjective quality of stereo codec, and achieve the effect of improving quality

Active Publication Date: 2012-05-09
HUAWEI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] However, the existing down-mixing method has the problem of the down-mixing performance of the stereo signal whose left and right channels are out of phase and often jumps, and the phase difference between the left and right channels changes quickly, which reduces the subjective quality of stereo encoding and decoding.

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  • Down-mixing signal generating and reducing method and device

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Embodiment 1

[0041] Embodiment 1: In one embodiment of the present invention, the first audio channel is the left audio channel.

[0042] The phase difference between the downmix signal and the left channel signal in each frequency band is calculated according to the following formula:

[0043] θ ( b ) = 1 1 + c ( b ) · IPD ( b ) ;

[0044] where c(b)=10 CLD(b)10 .

[0045] CLD(b) is the channel energy ratio of the bth frequency band, c(b) is an intermediate value variable used for calculation, IPD(b) is the channel phase difference of the bth frequency band, θ(b ) is the phase difference between the downmix signal and the first channel signal in the b-th frequency band.

[0046] The grea...

Embodiment 2

[0051] Embodiment 2: In another embodiment of the present invention, the first audio channel is the right audio channel.

[0052] The phase difference between the downmix signal and the right channel signal in each frequency band is calculated according to the following formula:

[0053] θ ( b ) = c ( b ) 1 + c ( b ) · IPD ( b ) ;

[0054] where c(b)=10 CLD(b)10 .

[0055] CLD(b) is the channel energy ratio of the bth frequency band, c(b) is an intermediate value variable used for calculation, IPD(b) is the channel phase difference of the bth frequency band, θ(b ) is the phase difference between ...

Embodiment 3

[0061] Embodiment 3: In yet another embodiment of the present invention, the first sound channel is a sound channel with a larger signal amplitude among the left sound channel and the right sound channel.

[0062] If the amplitude of the left channel signal is greater than the amplitude of the right channel signal, the first channel is the left channel, and the phase difference between the downmix signal and the channel with the greater signal amplitude in the left and right channels is according to Formula calculation:

[0063] θ ( b ) = 1 1 + c ( b ) · IPD ( b ) ;

[0064] where c(b)=10 CLD(b) / 10 .

[0065] S107 calculates the frequency domain downmix signal, and the frequen...

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Abstract

The embodiment of the invention provides a down-mixing signal generating method which comprises the steps of: carrying out time and frequency conversion on a received left channel signal and a received right channel signal to obtain a frequency domain signal, dividing the frequency domain signal into a plurality of frequency bands; computing a channel energy ratio and a channel phase difference of each frequency band; computing a phase difference of a down-mixing signal and a first channel signal in each frequency band according to the channel energy ratio and the channel phase difference; and computing a frequency domain down-mixing signal according to the phase difference of the left channel signal, the right channel signal, the down-mixing channel and the first channel signal in each frequency band. According to the method, the quality of coding and decoding dimensional sound is effectively improved.

Description

technical field [0001] The invention relates to the field of stereo coding and decoding, in particular to a method and device for generating and restoring a downmix signal. Background technique [0002] In the existing stereo coding methods, most methods down-mix the left and right channel signals to obtain a mono signal, and transmit the sound field information of the left and right channels as sideband signals. The sound field information of the left and right channels usually includes the energy ratio of the left and right channels, the phase difference between the left and right channels, the cross-correlation parameters of the left and right channels, and the phase difference parameters between the first channel or the second channel and the downmix signal. Existing methods encode these parameters as side information and send to the decoder to recover the stereo signal. [0003] Among these methods, the down-mixing method, the extraction and synthesis of sound field in...

Claims

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Application Information

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IPC IPC(8): G10L19/00G10L19/02G10L19/008
CPCG10L19/008G10L19/00G10L19/02H04S3/02
Inventor 吴文海苗磊郎玥大卫·维雷特
Owner HUAWEI TECH CO LTD
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