Stereo coding method and device

[0031] Example 1:

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

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

[0034] Step 102: The left channel frequency domain signal and the right channel frequency domain signal in the frequency domain are down-mixed to generate a mono downmix signal (DMX), the bits after encoding and quantization 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] Spatial parameters are parameters representing spatial characteristics of stereo signals, such as ILD parameters.

[0036] Step 103: Use the left and right channel signals in the frequency domain to estimate the group delay (Group Delay)

[0041] Embodiment 2:

[0042] figure 2 It is a schematic diagram of another stereo coding 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 a stereo left channel signal X in the frequency domain 1 (k) and the 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 spatial parameters, quantizing to form side information and transmitting, which may include the following steps:

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

[0046] Step 2022, encode the quantized mono downmix signal DMX, and trans

[0076] Combined with the above-mentioned preprocessing of the cross-correlation function time-domain signal, the group delay and group phase of the stereo signal are estimated in step 2033 using the same estimation method, or can be estimated separately. Specifically, at least the following estimated group phase and Implementation of group delay:

[0077] Step 2033 Embodiment 1, such as Figure 4a shown:

[0078] According to the cross-correlation function time-domain signal or the index corresponding to the value with the largest amplitude in the processed cross-correlation function time-domain signal, the group delay is estimated, 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] Determine the relationship between the index corresponding to the value with the largest amplitude in the cross-correlation function of the time-domain signal an