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Stereo coding method and device

A stereo and encoding technology, applied in the multimedia field, can solve the problems of inability to achieve realistic restoration, uncomfortable listening experience of the listener, and inability to meet the recovery requirements, and achieve the effect of improving encoding efficiency and enhancing sound field effects.

Inactive Publication Date: 2013-10-23
HUAWEI TECH CO LTD
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  • Claims
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AI Technical Summary

Problems solved by technology

ILD is a ubiquitous signal characteristic parameter that reflects the sound field signal. ILD can better reflect the energy of the sound field. However, stereo sound often has background space and sound fields in the left and right directions. It is not enough to restore the original stereo sound only by transmitting ILD to restore the stereo sound. Signal requirements, so a scheme to transmit more parameters to better restore the stereo signal was proposed. In addition to extracting the most basic ILD parameters, it also proposed to transmit the phase difference between the left and right channels (IPD: InterChannel Phase Difference) and the left and right channels. Cross-correlation ICC parameters, sometimes including the phase difference (OPD) parameters of the left channel and the downmix signal, these parameters reflecting the background space of the stereo signal and the sound field information in the left and right directions and the ILD parameters are encoded as side information and sent to Decoder to restore stereo signal
[0003] Coding bit rate is one of the important evaluation factors of multimedia signal coding performance. The adoption of low bit rate is the common goal of the industry. The existing stereo coding technology transmits LPD, ICC and OPD parameters while transmitting ILD. It is necessary to improve the coding Code rate, because LPD, ICC, and OPD parameters are local characteristic parameters of the signal, which are used to reflect the sub-band information of the stereo signal, and the LPD, ICC, and OPD parameters of the encoded stereo signal need to encode LPD for each sub-band of the stereo signal , ICC and OPD parameters, for each sub-band of the stereo signal, each sub-band IPD coding needs multiple bits, each sub-band ICC coding needs multiple bits, and so on, then the stereo coding parameters need a lot of Only the number of bits can enhance the information of the sound field. Under the lower bit rate requirement, only part of the sub-band can be enhanced, and the effect of realistic restoration cannot be achieved, resulting in a large gap between the restored stereo information and the original input signal under the low bit rate. The gap, in terms of auditory effect, will bring extremely uncomfortable auditory experience to the listener

Method used

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Experimental program
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Embodiment 1

[0032] figure 1 A schematic diagram of the implementation of a stereo coding method, including:

[0033] Step 101: Transform the time domain stereo left channel signal and the right channel signal into the frequency domain to form the left channel signal and the right channel signal in the frequency domain.

[0034] Step 102: The frequency-domain signal of the left channel and the frequency-domain signal of the right channel in the frequency domain are downmixed to generate a mono-channel downmix signal (DMX), and the encoded and quantized bits of the DMX signal are transmitted, and the extracted frequency domain The spatial parameters of the upper left channel signal and the right channel signal are quantized and encoded.

[0035] The spatial parameter is a parameter representing the spatial characteristics of a stereo signal, such as an ILD parameter.

[0036] Step 103: Estimate a group delay (Group Delay) and a group phase (Group Phase) between the left channel signal and...

Embodiment 2

[0042] figure 2 It is a schematic diagram of another stereo encoding method embodiment, including:

[0043] Step 201, transform the time domain stereo left channel signal and the right channel signal to the frequency domain to form the stereo left channel signal X on the frequency domain 1 (k) and right channel signal X 2 (k), where k is the index value of the frequency point of the frequency signal.

[0044] Step 202, performing a downmix operation on the left channel signal and the right channel signal in the frequency domain, encoding and quantizing the downmix signal and transmitting, and encoding stereo space parameters, quantizing to form side information and transmitting, may include the following steps:

[0045] In step 2021, the left channel signal and the right channel signal in the frequency domain are downmixed to generate a synthesized mono channel downmix signal DMX.

[0046] Step 2022, encode the quantized mono-channel downmix signal DMX, and transmit the qu...

Embodiment approach

[0077] Step 2033 implementation mode one, such as Figure 4a Shown:

[0078] According to the cross-correlation function time-domain signal or based on the index corresponding to the value with the largest amplitude in the processed cross-correlation function time-domain signal, the group delay is obtained, and the phase angle corresponding to the cross-correlation function corresponding to the group delay is obtained, and the group phase is estimated. , including the following steps:

[0079] Judging the relationship between the index corresponding to the value with the largest amplitude in the cross-correlation function of the time-domain signal and the symmetrical interval related to the transformation length N, in one embodiment, if the index corresponding to the value with the largest amplitude in the cross-correlation function of the time-domain signal is less than or equal to N / 2, then the group delay is equal to the index corresponding to the value with the largest am...

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Abstract

The embodiment of the invention relates to a stereo coding method, which comprises the following steps of transforming a left channel signal and a right channel signal of stereo in a time domain into a frequency domain to form a left channel signal and a right channel signal in the frequency domain; performing down-mixing on the left channel signal and the right channel signal in the frequency domain to generate a single-channel down-mixed signal, and transmitting bits of the coded and quantized down-mixed signal; extracting spatial parameters of the left channel signal and the right channel signal in the frequency domain; estimating a group delay and a group phase between the left and right channels of the stereo by utilizing the left channel signal and the right channel signal in the frequency domain; and quantitatively coding the group delay, the group phase and the spatial parameters to achieve high stereo coding performance under a low code rate.

Description

technical field [0001] The embodiments of the present invention relate to the field of multimedia, and in particular to a stereo processing technology, specifically a stereo encoding method and device. Background technique [0002] The existing stereo coding methods include intensity stereo, BCC (Binaual Cure Coding) and PS (Parametric-Stereo coding) coding methods. Usually, using intensity coding needs to extract the energy ratio ILD (InterChannel Level Difference) parameter between the left and right channels , encode the ILD parameters as side information, and send them to the decoder first to help restore the stereo signal. ILD is a ubiquitous signal characteristic parameter that reflects the sound field signal. ILD can better reflect the energy of the sound field. However, stereo sound often has background space and sound fields in the left and right directions. It is not enough to restore the original stereo sound only by transmitting ILD to restore the stereo sound. ...

Claims

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Application Information

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IPC IPC(8): G10L19/008G10L19/06G10L19/22
Inventor 吴文海苗磊郎玥张琦
Owner HUAWEI TECH CO LTD
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