Multi-channel signal encoding method, multi-channel signal decoding method, encoder, and decoder

Abstract

To provide a multi-channel signal encoding method, a multi-channel signal decoding method, an encoder, and a decoder for improving encoding efficiency.SOLUTION: An encoding method includes the steps of: determining a downmix signal and reverberation gain parameters corresponding to different subbands for a first channel signal and a second channel signal within multi-channel signals (310); determining target reverberation gain parameters that need to be encoded within reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal (320); generating parameter indication information used to indicate the subband corresponding to the target reverberation gain parameters (330); and encoding the target reverberation gain parameters, the parameter indication information, and the downmixed signal, to generate a bitstream (340).SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This application claims priority to Chinese Patent Application No. 201710236773.3, filed with the China Patent Office on April 12, 2017, and entitled "MULTI-CHANNEL SIGNAL ENCODING METHOD, MULTI-CHANNEL SIGNAL DECODING METHOD, ENCODER, AND DECODER," which is incorporated herein by reference in its entirety.

[0002] The present application relates to the field of audio coding, and more particularly to a multi-channel signal encoding method, a multi-channel signal decoding method, an encoder, and a decoder. [Background technology]

[0003] As the quality of life improves, people's demands for high-quality audio increase. Compared with mono audio, stereo audio provides a sense of direction and distribution for each sound source, and achieves improved clarity, intelligibility, and a sense of localization. Therefore, stereo audio is very popular.

[0004] Stereo processing techniques mainly include Mid / Sid (MS) coding, Intensity Stereo (IS) coding, and Parametric Stereo (PS) coding.

[0005] In the prior art, when PS coding is used to code a multi-channel signal, the encoder needs to calculate a reverberation gain parameter corresponding to each subband of the channel signal and encode the reverberation gain parameter corresponding to each subband of the channel signal, so that the decoder can perform reverberation processing on each subband of the channel signal based on the reverberation gain parameter corresponding to each subband of the channel signal. However, a relatively large amount of bits needs to be occupied to encode the reverberation gain parameter corresponding to each subband of the channel signal, and in some cases, performing reverberation processing on each subband of the channel signal may reduce the auditory effect. Summary of the Invention [Means for solving the problem]

[0006] The present application provides a multi-channel signal encoding method, a multi-channel signal decoding method, an encoder, and a decoder to improve coding efficiency.

[0007] According to a first aspect, there is provided a multi-channel signal encoding method, the method including the steps of: determining reverberation gain parameters corresponding to a down-mix signal of a first channel signal and a second channel signal in the multi-channel signal and different sub-bands of the first channel signal and the second channel signal; determining target reverberation gain parameters to be encoded within the reverberation gain parameters corresponding to the different sub-bands of the first channel signal and the second channel signal; generating parameter indication information, where the parameter indication information is used to indicate the sub-bands corresponding to the target reverberation gain parameters; and encoding the target reverberation gain parameters, the parameter indication information, and the down-mix signal to generate a bitstream.

[0008] In the present application, when the first channel signal and the second channel signal are encoded, reverberation gain parameters corresponding to only some subbands of the first channel signal and the second channel signal may be encoded. Compared with the prior art scheme in which reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal need to be encoded, bit overhead can be reduced to a certain extent and coding efficiency can be improved. Specifically, when reverberation gain parameters corresponding to some subbands are encoded, a large amount of saved bits can be used to code other parameters or allocate more bits to the downmix signal, thereby improving overall coding performance.

[0009] Referring to the first aspect, in some implementation forms of the first aspect, determining a target reverberation gain parameter to be encoded within reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes determining the target reverberation gain parameter based on at least one of an energy of the first channel signal and an energy of the second channel signal, an inter-channel coherence (IC) between the first channel signal and the second channel signal, an energy of the downmix signal, and an inter-channel level difference (ILD) between the first channel signal and the second channel signal.

[0010] The coherence between the first and second channel signals can be determined based on the energy of the channel signals or the energy, IC, ILD, etc. of the downmix signal. The target reverberation gain parameter to be encoded can be appropriately determined from the reverberation gain parameters corresponding to all subbands of the first and second channel signals based on the coherence between the first and second channel signals. Therefore, bits can be saved to a certain extent by taking into account the quality of the channel signals, and coding efficiency can be improved. Specifically, when the coherence between the first and second channel signals is relatively low, only the reverberation gain parameters corresponding to the subbands in the low-frequency parts of the first and second channel signals can be encoded. When the coherence between the first and second channel signals is relatively high, in addition to the reverberation gain parameters corresponding to the subbands in the low-frequency parts of the first and second channel signals, the reverberation gain parameters corresponding to the subbands in the high-frequency parts of the first and second channel signals can also be encoded.

[0011] Referring to the first aspect, in some implementation forms of the first aspect, the step of determining a target reverberation gain parameter that needs to be encoded within the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes the step of determining the target reverberation gain parameter based on at least one of a coherence between the energy of the first channel signal and the energy of the downmix signal and a coherence between the energy of the second channel signal and the energy of the downmix signal.

[0012] The values ​​of the energy of the first channel signal, the energy of the second channel signal, and the energy of the downmix signal may be values ​​obtained after a normalization process.

[0013] The coherence between both the first and second channel signals and the downmix signal can be conveniently measured using the energy of the channel signals, i.e., the target reverberation gain parameter that needs to be encoded can be conveniently determined by comparing the difference between the energy of the channel signals and the energy of the downmix signal. Specifically, when the difference between the energy of the channel signals and the energy of the downmix signal is relatively large, the coherence between the channel signals and the downmix signal can be considered relatively low, and in this case, only the reverberation gain parameter corresponding to the subbands in the low-frequency part of the channel signals can be encoded.

[0014] With reference to the first aspect, in some implementation forms of the first aspect, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the step of determining a target reverberation gain parameter based on at least one of a coherence between an energy of the first channel signal and an energy of the downmix signal and a coherence between an energy of the second channel signal and an energy of the downmix signal includes: determining a first difference value between the energy of the first channel signal and the energy of the downmix signal, where the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the downmix signal in the plurality of frequency bins; and determining, when the first difference value is greater than a first threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is the target reverberation gain parameter, where the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal.

[0015] With reference to the first aspect, in some implementation forms of the first aspect, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the step of determining a target reverberation gain parameter based on at least one of a coherence between the energy of the first channel signal and the energy of the downmix signal and a coherence between the energy of the second channel signal and the energy of the downmix signal includes: determining a second difference value between the energy of the second channel signal and the energy of the downmix signal, where the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the downmix signal in the plurality of frequency bins; and determining, when the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is the target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0016] Referring to the first aspect, in some implementation forms of the first aspect, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the step of determining the target reverberation gain parameter based on at least one of a coherence between an energy of the first channel signal and an energy of the downmix signal and a coherence between an energy of the second channel signal and an energy of the downmix signal includes a step of determining a first difference value between the energy of the first channel signal and the energy of the downmix signal, wherein the first difference value indicates a sum of absolute values ​​of the difference values ​​between the energy of the first channel signal and the energy of the downmix signal in the plurality of frequency bins. determining a second difference value between the energy of the second channel signal and the energy of the downmix signal, where the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the downmix signal in a plurality of frequency bins; and determining, when the first difference value is greater than a first threshold and the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is a target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0017] The difference value between the energy of the first channel signal and the energy of the downmix signal in the plurality of frequency bins and the difference value between the energy of the second channel signal and the energy of the downmix signal in the plurality of frequency bins may be values ​​obtained after a normalization process.

[0018] When the coherence between the first channel signal or the second channel signal and the downmix signal is relatively high, the first channel signal and the second channel signal may be considered to be two channel signals that are relatively similar to each other (when the two channel signals are relatively similar, a mixed signal obtained by mixing the two channel signals is relatively similar to the two channel signals before mixing).When the coherence between the first channel signal or the second channel signal and the downmix signal is relatively low, the first channel signal and the second channel signal may be considered to be two channel signals that are relatively different from each other.

[0019] The coherence between the first channel signal and the downmix signal is used as an example. The coherence between the first channel signal and the downmix signal may be measured by using a first difference value between the energy of the first channel signal and the energy of the downmix signal. When the first difference value is relatively large, the coherence between the first channel signal and the downmix signal may be considered to be relatively low. When the first difference value is relatively small, the coherence between the first channel signal and the downmix signal may be considered to be relatively high.

[0020] The difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal can be conveniently determined by comparing the difference values ​​between the energy of both the first channel signal and the energy of the second channel signal and the energy of the downmix signal in multiple frequency bins to further determine the target. Thus, it is not necessary to compare the energy of the first channel signal and the energy of the second channel signal in all frequency bands.

[0021] When the energy of the first channel signal and / or the second channel signal is relatively different from the energy of the downmix signal, encoding reverberation gain parameters corresponding to some frequency subbands of the first channel signal and the second channel signal can not only save bits to a certain extent but also improve coding performance. However, in the prior art, reverberation gain parameters corresponding to all frequency subbands of the first channel signal and the second channel signal are encoded. In this case, since the difference between the first channel signal and the second channel signal is relatively large, if reverberation gain parameters corresponding to all frequency subbands are still encoded, the reverberation processing is performed based on the reverberation gain parameters for all frequency bands, and the final restored first channel signal and second channel signal will have relatively large distortion compared to the original signals.

[0022] With reference to the first aspect, in some implementation forms of the first aspect, the frequency of the first frequency band is smaller than the frequency of another frequency band different from the first frequency band in the first channel signal and the second channel signal.

[0023] It should be appreciated that the first frequency band may be a low frequency band.

[0024] When the difference between the first channel signal and the second channel signal is relatively large, the difference between the two channel signals is usually relatively large in the high frequency part, but relatively small in the low frequency part. However, the channel signal in the low frequency part has a greater impact on the human auditory experience. Therefore, when the difference between the first channel signal and the second channel signal is relatively large, only the reverberation gain parameter corresponding to the subband in the low frequency part may be coded. In this way, not only can the coding bits be saved, but also the auditory experience can be guaranteed.

[0025] Referring to the first aspect, in some implementations of the first aspect, a method includes: determining, when the first difference value is equal to or less than a first threshold and the second difference value is equal to or less than a second threshold, reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal as target reverberation gain parameters; Further includes:

[0026] Referring to the first aspect, in some implementation forms of the first aspect, when the first difference value is equal to or less than a first threshold or the second difference value is equal to or less than a second threshold, reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal are determined as target reverberation gain parameters.

[0027] When the difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal is relatively large, only the reverberation gain parameters corresponding to some subbands may be coded in order to reduce bit overhead during coding and to avoid signal distortion during reverberation processing as much as possible.

[0028] However, when the difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal is relatively small, the signal distortion caused by the reverberation processing on the channel signals is very small. To achieve a better auditory effect, the reverberation gain parameters corresponding to all subbands may be coded.

[0029] With reference to the first aspect, in some implementation forms of the first aspect, the multiple frequency bins are within a second frequency band of each of the first channel signal and the second channel signal, and the frequency of the second frequency band is greater than the frequency of another frequency band different from the second frequency band in the first channel signal and the second channel signal.

[0030] The difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal can be conveniently determined by comparing difference values ​​between the energy of both the first channel signal and the energy of the second channel signal and the energy of the downmix signal in a plurality of frequency bins of the high frequency part.

[0031] Referring to the first aspect, in some implementation forms of the first aspect, the step of determining target reverberation gain parameters to be encoded within reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes the steps of: determining energies of N subbands of the downmix signal; determining M subbands from the N subbands, where the energy of any subband among the M subbands is greater than the energy of any subband among NM subbands within the N subbands excluding the M subbands, where both M and N are integers greater than 0 and M is less than N; and determining the target reverberation gain parameters based on a magnitude relationship between the energies of the M subbands and the energies of the NM subbands.

[0032] It should be understood that when the downmix signal is a wideband signal, the N subbands may be all subbands of the downmix signal, and when the downmix signal is an ultra-wideband signal, the N subbands may be subbands of the downmix signal in the wideband part.

[0033] The coherence between the first channel signal and the second channel signal can be determined based on the energy of different subbands of the downmix signal, and further, the target reverberation gain parameter that needs to be encoded is determined based on the coherence between the first channel signal and the second channel signal.

[0034] The downmix signal may be a wideband signal or an ultra-wideband signal. When the downmix signal is a wideband signal, the N subbands may be all subbands of the downmix signal, and when the downmix signal is an ultra-wideband signal, the N subbands may be subbands of the downmix signal in the wideband part.

[0035] Additionally, alternatively, the M subbands may be determined based on the amplitude of each subband of the downmix signal, i.e., the amplitude of any subband among the M subbands of the downmix signal is greater than the amplitude of any subband among the NM subbands of the downmix signal. The value of M may be preset.

[0036] With reference to the first aspect, in some implementation forms of the first aspect, the step of determining the target reverberation gain parameter based on the magnitude relationship between the energies of the M subbands of the downmix signal and the energies of the NM subbands of the downmix signal includes the step of determining that the reverberation gain parameter corresponding to the subbands of the first frequency band of the first channel signal and the second channel signal is the target reverberation gain parameter when an average value of the energies of the M subbands is greater than K times the average value of the energies of the NM subbands, where K is a real number greater than 0.

[0037] With reference to the first aspect, in some implementation forms of the first aspect, the step of determining the target reverberation gain parameter based on the magnitude relationship between the energies of the M subbands of the downmix signal and the energies of the NM subbands of the downmix signal includes the step of determining that the reverberation gain parameter corresponding to the subbands of the first frequency band of the first channel signal and the second channel signal is the target reverberation gain parameter when the sum of the energies of the M subbands is greater than L times the sum of the energies of the NM subbands, where L is a real number greater than 0.

[0038] It is understood that K and L may have different values.

[0039] The energies of the N subbands of the downmix signal and the energies of the NM subbands of the downmix signal may be compared by comparing the average value of the energies of the M subbands with the average value of the energies of the NM subbands. To further reduce the complexity of the calculation, the sum of the energies of the M subbands and the sum of the energies of the NM subbands may be directly compared. In this way, the calculation process is simplified to a certain extent and efficiency is improved.

[0040] When the difference between the energy of M subbands having a relatively large energy and the energy of another subband having a relatively small energy is relatively large, the difference between the first channel signal and the second channel signal may be considered to be relatively large. In this case, reverberation gain parameters corresponding to subbands of some frequency bands in the first channel signal and the second channel signal may be determined as target reverberation gain parameters to be encoded. Specifically, the first frequency band may be a frequency band located in a low frequency portion of the first channel signal and the second channel signal.

[0041] Referring to the first aspect, in some implementation forms of the first aspect, the step of determining target reverberation gain parameters to be encoded in reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes the steps of: determining energy of N subbands of the downmix signal; determining M subbands from the N subbands, where the energy of any subband among the M subbands is greater than the energy of any subband among the N subbands excluding the M subbands; and determining, when an index value of a first subband among the M subbands is smaller than a preset index value, that a reverberation gain parameter corresponding to a subband of the first frequency band is the target reverberation gain parameter, where the frequency of any frequency bin in the first subband is greater than the frequency of any frequency bin in another subband among the M subbands excluding the first subband, and the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0042] When the index value of the subband with the highest frequency among the M subbands having relatively large energy is smaller than the preset index value, it can be considered that the energy distribution of the M subbands of the downmix signal is uneven, that is, the coherence between the first channel signal and the second channel signal is relatively small. In this case, only the reverberation gain parameters corresponding to the subbands of some frequency bands need to be coded.

[0043] Referring to the first aspect, in some implementation forms of the first aspect, the step of determining target reverberation gain parameters to be encoded in reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes the steps of: determining energies of N subbands of the downmix signal; determining J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, both N and J are integers greater than 0, and J is less than N; and determining the reverberation gain parameters corresponding to the J target subbands as the target reverberation gain parameters.

[0044] Based on the energy of each subband of the downmix signal, a predetermined number of subbands are directly selected from all subbands, and the reverberation gain parameters corresponding to the predetermined number of subbands are determined as target reverberation gain parameters, so that the reverberation gain parameters that need to be encoded can be selected more flexibly.

[0045] Referring to the first aspect, in some implementation forms of the first aspect, the energy of the downmix signal is determined based on the energy of the first channel signal and the energy of the second channel signal.

[0046] The energy of the downmix signal is estimated or inferred based on the energy of the first channel signal and the energy of the second channel signal, which can reduce the amount of calculation to a certain extent.

[0047] According to a second aspect, there is provided a multi-channel signal decoding method, the method including: receiving a bitstream; obtaining, based on the bitstream, a downmix signal of a first channel signal and a second channel signal in the multi-channel signal and parameter indication information, where the parameter indication information is used to indicate encoded target reverberation gain parameters in reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; obtaining the target reverberation gain parameter from the bitstream according to the parameter indication information; and determining the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameter.

[0048] In the present application, the target reverberation gain parameters encoded by the encoder can be determined using the parameter indication information, and then reverberation processing is performed on the corresponding subbands of the first channel signal and the second channel signal based on the target reverberation gain parameters.

[0049] According to a third aspect, there is provided a multi-channel signal encoding method, the method including: determining a downmix signal of a first channel signal and a second channel signal in the multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; determining target reverberation gain parameters to be encoded among the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal based on energies of N subbands of the downmix signal, where N is an integer greater than 0; and encoding the downmix signal and the target reverberation gain parameters.

[0050] In the present application, a certain number of subbands are directly selected from all subbands based on the energy of each subband of the downmix signal, so that the reverberation gain parameters to be coded can be selected more flexibly. In addition, compared with the method of determining the reverberation gain parameters corresponding to subbands of a fixed frequency band as the target reverberation gain parameters, the reverberation gain parameters corresponding to some subbands that may not be adjacent in the frequency domain can be directly selected as the target reverberation gain parameters.

[0051] With reference to the third aspect, in some implementation forms of the third aspect, the step of determining target reverberation gain parameters to be encoded within reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of the N subbands of the downmix signal includes the steps of determining J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, both N and J are integers greater than 0, and J is less than N; and determining the reverberation gain parameters corresponding to the J target subbands as the target reverberation gain parameters.

[0052] In the present application, based on the energy of each subband of the downmix signal, a predetermined number of subbands are directly selected from all subbands, and the reverberation gain parameters corresponding to the predetermined number of subbands are determined as target reverberation gain parameters, so that the reverberation gain parameters that need to be coded can be selected more flexibly.

[0053] According to a fourth aspect, there is provided a multi-channel signal decoding method, the method including the steps of: receiving a bitstream; determining a downmix signal of a first channel signal and a second channel signal in the multi-channel signal based on the bitstream; determining encoded target reverberation gain parameters among reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on energies of N subbands of the downmix signal, where N is an integer greater than 0; determining the target reverberation gain parameters based on the bitstream; and determining the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameters.

[0054] In the present application, the decoder side can directly determine the encoded target reverberation gain parameters in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of multiple subbands of the downmix signal, so that the bits occupied by the decoder side for transmitting the indication information indicating the encoded target reverberation gain parameters can be reduced, and the signaling overhead can be reduced to a certain extent.

[0055] With reference to the fourth aspect, in some implementation forms of the fourth aspect, the step of determining encoded target reverberation gain parameters among the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of the N subbands of the downmix signal includes the steps of determining J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, both N and J are integers greater than 0, and J is less than N; and determining the reverberation gain parameters corresponding to the J target subbands as the target reverberation gain parameters.

[0056] According to a fifth aspect, there is provided an encoder, the encoder including a module or unit configured to perform the method of the first aspect or various implementations of the first aspect.

[0057] According to a sixth aspect, there is provided a decoder, wherein the encoder includes a module or unit configured to perform the method of the second aspect or various implementations of the second aspect.

[0058] According to a seventh aspect, there is provided an encoder, the encoder including a module or unit configured to perform the method of the third aspect or various implementations of the third aspect.

[0059] According to an eighth aspect, there is provided a decoder, wherein the encoder includes a module or unit configured to perform the method of the fourth aspect or various implementations of the fourth aspect.

[0060] According to a ninth aspect, there is provided an encoder including a memory and a processor, the memory configured to store a program, and the processor configured to execute the program, wherein when the program is executed, the processor performs the method of the first aspect or various implementations of the first aspect.

[0061] According to a tenth aspect, there is provided a decoder including a memory and a processor, the memory configured to store a program, and the processor configured to execute the program, wherein when the program is executed, the processor performs a method of the second aspect or various implementations of the second aspect.

[0062] According to an eleventh aspect, there is provided an encoder including a memory and a processor, the memory configured to store a program, and the processor configured to execute the program, wherein when the program is executed, the processor performs a method of the third aspect or various implementation forms of the third aspect.

[0063] According to a twelfth aspect, there is provided a decoder including a memory and a processor, the memory configured to store a program and the processor configured to execute the program, wherein when the program is executed, the processor performs a method of the fourth aspect or various implementations of the fourth aspect.

[0064] According to a thirteenth aspect, there is provided a computer-readable medium, the computer-readable medium storing program code to be executed by a device, the program code including instructions used to perform the method of the first aspect or various implementations of the first aspect.

[0065] According to a fourteenth aspect, there is provided a computer-readable medium, the computer-readable medium storing program code to be executed by a device, the program code including instructions used to perform a method in the second aspect or various implementations of the second aspect.

[0066] According to a fifteenth aspect, there is provided a computer-readable medium, the computer-readable medium storing program code to be executed by a device, the program code including instructions used to perform a method in the third aspect or various implementations of the third aspect.

[0067] According to a sixteenth aspect, there is provided a computer-readable medium, the computer-readable medium storing program code to be executed by a device, the program code including instructions used to perform a method in the fourth aspect or various implementations of the fourth aspect. [Brief explanation of the drawings]

[0068] [Figure 1] 1 is a schematic flowchart of encoding a left channel signal and a right channel signal in the prior art; [Figure 2] 1 is a schematic flowchart of decoding a left channel signal and a right channel signal in the prior art; [Figure 3] 1 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application; [Figure 4] 1 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application; [Figure 5] 1 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application; [Figure 6] 1 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application; [Figure 7] 1 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application; [Figure 8] 1 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application; [Figure 9] 1 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application; [Figure 10]1 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application; [Figure 11] FIG. 2 is a schematic block diagram of an encoder according to an embodiment of the present application; [Figure 12] FIG. 2 is a schematic block diagram of a decoder according to an embodiment of the present application; [Figure 13] FIG. 2 is a schematic block diagram of an encoder according to an embodiment of the present application; [Figure 14] FIG. 2 is a schematic block diagram of a decoder according to an embodiment of the present application; [Figure 15] FIG. 2 is a schematic block diagram of an encoder according to an embodiment of the present application; [Figure 16] FIG. 2 is a schematic block diagram of a decoder according to an embodiment of the present application; [Figure 17] FIG. 2 is a schematic block diagram of an encoder according to an embodiment of the present application; [Figure 18] FIG. 2 is a schematic block diagram of a decoder according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0069] The following describes the technical solutions of the present application with reference to the accompanying drawings. In order to better understand the multi-channel signal encoding method and multi-channel signal decoding method in the embodiments of the present application, the following first briefly describes the multi-channel signal encoding method and multi-channel signal decoding method in the prior art with reference to Figures 1 and 2.

[0070] 1 shows a process of encoding a left channel signal and a right channel signal in the prior art. The encoding process shown in FIG. 1 specifically includes the following steps:

[0071] 110. Perform spatial parameter analysis and downmixing processing on the left channel signal (represented by L in the figure) and the right channel signal (represented by R in the figure).

[0072] Specifically, step 110 specifically includes: performing spatial parameter analysis on the left channel signal and the right channel signal to obtain spatial parameters of the left channel signal and spatial parameters of the right channel signal; and performing a downmixing process on the left channel signal and the right channel signal to obtain a downmix signal (the downmix signal obtained after the downmixing process is a mono audio signal, and the original two channels of the audio signal are combined into one channel of the audio signal by the downmixing process).

[0073] Spatial parameters (sometimes called spatial sensing parameters) include inter-channel coherence (IC), inter-channel level difference (ILD), inter-channel time difference (ITD), and inter-channel phase difference (IPD).

[0074] IC describes the cross-coherence or coherence between channels. This parameter determines the detection of sound field range and can improve spatial detection and sound stability of audio signals. ILD is used to distinguish the horizontal angle of a stereo source and describe the intensity difference between channels, which affects frequency components throughout the spectrum. ITD and IPD are spatial parameters that represent the horizontal direction of the sound source and describe the time and phase differences between channels. These parameters mainly affect frequency components below 2 kHz. For two-channel signals, ITD can represent the time delay between the left and right stereo channel signals, while IPD can represent the waveform similarity between the left and right stereo channel signals after time alignment. ILD, ITD, and IPD determine the detection of sound source location by the human ear, effectively determining sound source location and playing an important role in stereo signal restoration.

[0075] 120. Encode the downmix signal to obtain a bitstream.

[0076] 130. Encode the spatial parameters to obtain a bitstream.

[0077] 140. Obtain a bitstream by multiplexing the bitstream obtained by encoding the downmix signal and the bitstream obtained by encoding the spatial parameters.

[0078] The bitstream obtained by encoding may be stored or transmitted to a decoder-side device.

[0079] 2 shows a process of decoding a left channel signal and a right channel signal in the prior art. The decoding process shown in FIG. 2 specifically includes the following steps:

[0080] 210. Demultiplex the bitstream to separately obtain a bitstream obtained by encoding the downmix signal and a bitstream obtained by encoding the spatial parameters.

[0081] Based on the demultiplexed bitstream, the downmix signal and spatial parameters are obtained by decoding.

[0082] In step 210, the decoder side can decode the downmix signal and the spatial parameters separately.

[0083] The spatial parameters are used to indicate the IC of the left and right channel signals.

[0084] 220. Acquire decoherence signals.

[0085] Furthermore, a left channel signal and a right channel signal are obtained based on the decoded downmix signal and the decoherence signal of the current frame.

[0086] 230. Based on the spatial parameters, the left channel signal, and the right channel signal, obtain the left channel signal and the right channel signal that are finally output (represented by L′ and R′ in FIG. 2, respectively).

[0087] It should be understood that the left and right channel signals (represented by L' and R' in FIG. 2, respectively) in step 230 may be distorted to some extent compared to the left and right channel signals obtained by decoding and coded at the encoder side.

[0088] Specifically, the downmix signal may be filtered, and then the inter-channel coherence parameters are used to modify the filtered downmix signal to obtain a decoherence signal.

[0089] The purpose of generating the decoherence signal is to improve the reverberation of the stereo signal finally generated at the decoder side and widen the sound field width of the stereo signal, so that the output audio signal becomes mellower and fuller from the auditory point of view. Reverberation is essentially the effect of delay, such as reflecting and refracting the original audio signal differently, and then superimposing the reflected and refracted audio signals on the original audio signal before entering the human ear.

[0090] In the prior art, when a multi-channel signal is coded, the multi-channel signal is usually divided into multiple subbands, an IC corresponding to each subband is determined, and the IC corresponding to each subband is then coded. However, coding the IC corresponding to each subband inevitably increases the number of bits occupied during coding. In some cases, for example, when the coherence between the multiple channel signals is relatively low, the high-frequency portions of the multiple channel signals are relatively different. In this case, if the IC corresponding to the high-frequency portions of the multiple channel signals is still coded, and the decoder side performs reverberation processing on the high-frequency portions of the multiple channel signals based on the IC corresponding to the high-frequency portions of the multiple channel signals, the multiple restored channel signals will be significantly distorted.

[0091] Therefore, an embodiment of the present application provides a multi-channel signal encoding method, so that the reverberation gain parameters of some subbands in the multi-channel signal can be adaptively selected for encoding in order to use bits effectively. Hereinafter, the multi-channel signal encoding method in this embodiment of the present application will be described in detail with reference to the accompanying drawings.

[0092] 3 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application. The method of FIG. 3 may be performed by an encoder-side device or an encoder. The method of FIG. 3 includes the following steps:

[0093] 310. Determine a downmix signal of the first channel signal and the second channel signal in the multi-channel signal, and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal.

[0094] The multi-channel signal may be a plurality of channel signals. In addition, before step 310, the method may include a step of obtaining a first channel signal and a second channel signal in the multi-channel signal.

[0095] This embodiment of the present application does not impose any restrictions on the order between the process of determining a downmix signal and the process of determining reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, and the processes may be performed simultaneously or sequentially.

[0096] Specifically, the downmix signal may be obtained by performing a downmixing process on the first channel signal and the second channel signal. The spatial parameters of the first channel signal and the second channel signal are obtained by performing spatial parameter analysis on the first channel signal and the second channel signal. The spatial parameters include reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, as well as other spatial parameters such as IC, ILD, ITD, and IPD.

[0097] It should be understood that the first channel signal and the second channel signal correspond to the same spatial parameters, specifically, the first channel signal and the second channel signal also correspond to the same initial reverberation gain parameter, i.e., the spatial parameters of the first channel signal and the spatial parameters of the second channel signal are the same, and the initial reverberation gain parameter of the first channel signal and the initial reverberation gain parameter of the second channel signal are the same.

[0098] Furthermore, assuming that each of the first channel signal and the second channel signal includes 10 subbands and each subband corresponds to one reverberation gain parameter, the reverberation gain parameters of the first channel signal and the second channel signal corresponding to subbands with the same index value are the same.

[0099] In addition, the first channel signal, the second channel signal, and the downmix signal may be channel signals obtained after a normalization process.

[0100] 320. Determine target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal.

[0101] 330. Generate parameter indication information, which is used to indicate subbands corresponding to target reverberation gain parameters.

[0102] The parameter indication information can indicate the subband corresponding to the target reverberation gain parameter by using a flag bit. For example, each of the first and second channel signals includes 10 subbands (subband index numbers are 0 to 9), and the parameter indication information includes 10 flag bits, which consecutively correspond to the 10 subbands of each of the first and second channel signals. When the flag bit corresponding to a subband is 1, the reverberation gain parameter corresponding to the subband is the target reverberation gain parameter that needs to be encoded. However, when the flag bit corresponding to a subband is 0, the reverberation gain parameter corresponding to the subband is not the target reverberation gain parameter. In this way, when performing encoding, the encoder only encodes the reverberation gain parameters corresponding to the subbands whose flag bits are 1.

[0103] Alternatively, the parameter indication information may include only one flag bit, which may be 1 or 0. When the flag bit is 1, it indicates that the reverberation gain parameters of the selected target subband should be coded. When the flag bit is 0, it indicates that the reverberation gain parameters of all subbands should be coded.

[0104] Specifically, the index numbers of all subbands of the first channel signal and the second channel signal are 0 to 9, and the subbands with index numbers 0 to 5 are the target subbands. In this case, when the flag bit of the parameter instruction information is 1, the reverberation gain parameters of the subbands with index numbers 0 to 5 should be coded. When the flag bit of the parameter instruction information is 0, the reverberation gain parameters of the subbands with index numbers 0 to 9 should be coded.

[0105] 340. Encode the target reverberation gain parameters, parameter indication information, and the downmix signal to generate a bitstream.

[0106] In the present application, when the first channel signal and the second channel signal are encoded, reverberation gain parameters corresponding to only some subbands of the first channel signal and the second channel signal may be encoded, which can reduce bit overhead to a certain extent and improve coding efficiency compared to the prior art scheme in which reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal need to be encoded.

[0107] Specifically, when reverberation gain parameters corresponding to several subbands are coded, a large amount of saved bits can be used to code another parameter or allocate more bits to the downmix signal, thereby improving the overall coding performance.

[0108] For example, reverberation gain parameters corresponding to subbands in the low frequency part of the first channel signal and the second channel signal may be selected as target reverberation gain parameters that need to be encoded, and reverberation gain parameters corresponding to subbands in the high frequency part of the first channel signal and the second channel signal should not be encoded.

[0109] In some cases, when reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal are generated, reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal may be generated, i.e., all reverberation gain parameters of the first channel signal and the second channel signal are generated, and then only the target reverberation gain parameter among all the reverberation gain parameters is encoded during encoding.

[0110] Alternatively, to further improve coding efficiency, when spatial parameter analysis is performed on the first channel signal and the second channel signal, only a target reverberation gain parameter may be generated, and the remaining reverberation gain parameters that do not need to be coded may not be generated. Specifically, if the target reverberation gain parameter corresponds to a target subband of the first channel signal and the second channel signal, when spatial parameter analysis is performed on the first channel signal and the second channel signal, only the reverberation gain parameter corresponding to the target subband of the first channel signal and the second channel signal may be determined, and reverberation gain parameters corresponding to other subbands of the first channel signal and the second channel signal do not need to be determined. In this way, coding efficiency can be further improved.

[0111] In some cases, in one embodiment, determining target reverberation gain parameters that need to be encoded within reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes determining the target reverberation gain parameters based on at least one of the energy of the first channel signal and the energy of the second channel signal, the IC between the first channel signal and the second channel signal, the magnitude of the energy of different subbands of the downmix signal, and the ILD between the first channel signal and the second channel signal.

[0112] Specifically, the coherence between the first channel signal and the second channel signal can be determined based on the energy of the first channel signal and the energy of the second channel signal or the energy of the downmix signal, the inter-channel coherence between the first channel signal and the second channel signal, and the inter-channel level difference between the first channel signal and the second channel signal. In addition, the target reverberation gain parameter that needs to be encoded is appropriately determined from the reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal based on the coherence between the first channel signal and the second channel signal, so that bits can be saved to a certain extent and coding efficiency can be improved.

[0113] For example, when the coherence between the first channel signal and the second channel signal is relatively low, only the reverberation gain parameters corresponding to the subbands in the low frequency parts of the first channel signal and the second channel signal may be encoded. When the coherence between the first channel signal and the second channel signal is relatively high, in addition to the reverberation gain parameters corresponding to the subbands in the low frequency parts of the first channel signal and the second channel signal, the reverberation gain parameters corresponding to the subbands in the high frequency parts of the first channel signal and the second channel signal may also be encoded. In other words, when the coherence between the first channel signal and the second channel signal is relatively high, the reverberation gain parameters corresponding to all the subbands of the first channel signal and the second channel signal may be encoded.

[0114] When the target reverberation gain parameter is determined based on the IC between the first channel signal and the second channel signal, the size of the IC value between the first channel signal and the second channel signal may be determined, and the coherence between the first channel signal and the second channel signal may be determined based on the size of the IC value. For example, when the IC value between the first channel signal and the second channel signal is relatively small (in this case, the coherence between the first channel signal and the second channel signal may be considered to be relatively low), the reverberation gain parameter corresponding to the subband of the low-frequency part of the first channel signal and the second channel signal may be determined as the target reverberation gain parameter. When the IC value between the first channel signal and the second channel signal is relatively large (in this case, the coherence between the first channel signal and the second channel signal may be considered to be relatively high), the reverberation gain parameters corresponding to the subbands in the low frequency portion and the subbands in the high frequency portion of the first channel signal and the second channel signal (i.e., the subbands in all frequency bands of the first channel signal and the second channel signal) may be determined as the target reverberation gain parameters.

[0115] Optionally, in one embodiment, determining target reverberation gain parameters that need to be encoded within reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes determining the target reverberation gain parameters based on at least one of a coherence between the energy of the first channel signal and the energy of the downmix signal and a coherence between the energy of the second channel signal and the energy of the downmix signal.

[0116] That is, when the target reverberation gain parameter is determined, the target reverberation gain parameter may be determined separately based on the coherence between the energy of the first channel signal and the energy of the downmix signal or the coherence between the energy of the second channel signal and the energy of the downmix signal, or the target reverberation gain parameter may be determined jointly based on the coherence between the energy of the first channel signal and the energy of the downmix signal and the coherence between the energy of the second channel signal and the energy of the downmix signal.

[0117] Specifically, in some embodiments, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the step of determining the target reverberation gain parameter based on at least one of the coherence between the energy of the first channel signal and the energy of the downmix signal and the coherence between the energy of the second channel signal and the energy of the downmix signal includes the steps of: determining a first difference value between the energy of the first channel signal and the energy of the downmix signal, where the first difference value is used to indicate a sum of absolute values ​​of the difference values ​​between the energy of the first channel signal and the energy of the downmix signal in the plurality of frequency bins; and determining, when the first difference value is greater than a first threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is the target reverberation gain parameter, where the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal.

[0118] In another embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the step of determining the target reverberation gain parameter based on at least one of the coherence between the energy of the first channel signal and the energy of the downmix signal and the coherence between the energy of the second channel signal and the energy of the downmix signal includes the steps of: determining a second difference value between the energy of the second channel signal and the energy of the downmix signal, where the second difference value is used to indicate a sum of absolute values ​​of the difference values ​​between the energy of the second channel signal and the energy of the downmix signal in the plurality of frequency bins; and determining, when the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is the target reverberation gain parameter, where the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal.

[0119] In another embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the step of determining the target reverberation gain parameter based on at least one of the coherence between the energy of the first channel signal and the energy of the downmix signal and the coherence between the energy of the second channel signal and the energy of the downmix signal includes the step of determining a first difference value between the energy of the first channel signal and the energy of the downmix signal, wherein the first difference value is used to indicate a sum of absolute values ​​of the difference values ​​between the energy of the first channel signal and the energy of the downmix signal in the plurality of frequency bins. determining a second difference value between the energy of the second channel signal and the energy of the downmix signal, where the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the downmix signal in a plurality of frequency bins; and determining, when the first difference value is greater than a first threshold and the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is a target reverberation gain parameter, where the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal.

[0120] The difference value between the energy of the first channel signal and the energy of the downmix signal in the plurality of frequency bins and the difference value between the energy of the second channel signal and the energy of the downmix signal in the plurality of frequency bins may be values ​​obtained after a normalization process.

[0121] The first threshold and the second threshold may be preset. In addition, the first threshold and the second threshold may be the same or different.

[0122] The coherence between both the first and second channel signals and the downmix signal can be conveniently measured based on the energy of the channel signals, i.e., the target reverberation gain parameter that needs to be encoded can be conveniently determined by comparing the difference between the energy of the channel signals and the energy of the downmix signal.

[0123] For example, when the difference between the energy of the first channel signal and the energy of the downmix signal is relatively large, the coherence between the first channel signal and the downmix signal may be considered to be relatively low, and in this case, only the reverberation gain parameters corresponding to the subbands in the low frequency part of the first channel signal may be encoded.

[0124] When the coherence between the first channel signal or the second channel signal and the downmix signal is relatively high, the first channel signal and the second channel signal may be considered to be two channel signals that are relatively similar to each other (when the two channel signals are relatively similar, a mixed signal obtained by mixing the two channel signals is relatively similar to the two channel signals before mixing).When the coherence between the first channel signal or the second channel signal and the downmix signal is relatively low, the first channel signal and the second channel signal may be considered to be two channel signals that are relatively different from each other.

[0125] The coherence between the first channel signal and the downmix signal is used as an example. The coherence between the first channel signal and the downmix signal may be measured by using a first difference value between the energy of the first channel signal and the energy of the downmix signal. When the first difference value is relatively large, the coherence between the first channel signal and the downmix signal may be considered to be relatively low. When the first difference value is relatively small, the coherence between the first channel signal and the downmix signal may be considered to be relatively high.

[0126] When at least one of the first difference value and the second difference value exceeds a corresponding threshold, it can be considered that the coherence between the first channel signal and the second channel signal is relatively low. In this case, reverberation gain parameters corresponding to some frequency subbands of the first channel signal and the second channel signal are coded, which not only saves bits to a certain extent but also improves coding performance. However, in this case, in the prior art, reverberation gain parameters corresponding to all frequency subbands of the first channel signal and the second channel signal are still coded. In this case, since the difference between the first channel signal and the second channel signal is relatively large, if reverberation gain parameters corresponding to all frequency subbands are still coded, the reverberation processing is performed based on the reverberation gain parameters of all frequency subbands, and the finally restored first channel signal and second channel signal have relatively large distortion compared to the original signals.

[0127] Indeed, alternatively, the reverberation gain parameters corresponding to the subbands of the first frequency band of the first channel signal and the second channel signal can be determined as the target reverberation gain parameters only when both the first difference value and the second difference value are greater than the corresponding thresholds.

[0128] The frequency of the first frequency band may be lower than the frequency of another frequency band different from the first frequency band in the first channel signal and the second channel signal. Specifically, the first frequency band may be a frequency band having the lowest frequency in the first channel signal and the second channel signal. That is, a reverberation gain parameter corresponding to a subband of the lowest frequency band in the first channel signal and the second channel signal may be determined as the target reverberation gain parameter.

[0129] Alternatively, the first frequency band may be a frequency band of intermediate frequency values ​​in the first channel signal and the second channel signal (some frequencies of all frequency bands of the first channel signal and the second channel signal are greater than the frequencies of the first frequency band, and other frequencies of all frequency bands are less than the frequencies of the first frequency band), i.e., the reverberation gain parameters corresponding to the subband of intermediate frequency values ​​of the first channel signal and the second channel signal may be determined as the target reverberation gain parameters.

[0130] In some cases, the plurality of frequency bins are within a second frequency band of each of the first channel signal and the second channel signal, and the frequency of the second frequency band is greater than the frequency of another frequency band different from the second frequency band in the first channel signal and the second channel signal.

[0131] That is, the plurality of frequency bins are located in a second frequency band having a relatively high frequency. Therefore, the difference value between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal can be conveniently determined by comparing the difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal in the plurality of frequency bins in the high frequency part. Therefore, it is not necessary to compare the difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal over the entire frequency band, which simplifies the calculation process.

[0132] The difference value between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal can be conveniently determined by comparing the difference between the energy of both the first channel signal and the energy of the second channel signal and the energy of the downmix signal in multiple frequency bins. Furthermore, the target reverberation gain parameter is determined based on the difference value between the energy of both the first channel signal and the energy of the second channel signal and the energy of the downmix signal, and there is no need to compare the difference between the energy of both the first channel signal and the energy of the second channel signal and the energy of the downmix signal in all frequency bands.

[0133] Optionally, in one embodiment, the method of FIG. 3 further includes determining, as target reverberation gain parameters, reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal when the first difference value is less than or equal to a first threshold and the second difference value is less than or equal to a second threshold.

[0134] When the first difference value is equal to or less than the first threshold and the second difference value is equal to or less than the second threshold, the difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal is relatively small. In this case, it may be considered that the coherence between the first channel signal and the second channel signal is relatively large. To improve the reverberation feeling of the output channel signal, reverberation gain parameters corresponding to all subbands may be coded.

[0135] When the difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal is relatively large, only reverberation gain parameters corresponding to some subbands may be coded to reduce bit overhead during coding and to avoid signal distortion caused by the reverberation process as much as possible.When the difference between the energy of both the first channel signal and the second channel signal and the energy of the downmix signal is relatively small, signal distortion caused by the reverberation process on the channel signals is very small.To achieve a better auditory effect, reverberation gain parameters corresponding to all subbands may be coded.

[0136] Specifically, when the first channel signal is a left channel signal and the second channel signal is a right channel signal, the first difference value and the second difference value may be calculated based on the following formula:

number

number

[0137] where diff_l_h is a first difference value, diff_r_h is a second difference value, the frequency band of each of the left channel signal and the right channel signal includes a high-frequency portion and a low-frequency portion, M1 is a start frequency bin of the high-frequency portion, M2 is an end frequency bin of the high-frequency portion, mag_l[k] is an energy or amplitude value of the left channel signal at a frequency bin having an index k between M1 and M2, mag_r[k] is an energy or amplitude value of the right channel signal at a frequency bin having an index k between M1 and M2, and mag_dmx[k] is an energy or amplitude value of the downmix signal at a frequency bin having an index k between M1 and M2, and mag_dmx[k] may be calculated using the downmix signal itself or may be calculated based on the energy or amplitude values ​​of the left channel signal and the right channel signal.

[0138] After the first difference value and the second difference value are calculated based on equations (1) and (2), an inter-frame smoothing process may be further performed on the first difference value and the second difference value (the smoothing process may be performed on the first difference value, the second difference value, and the difference value calculated in the previous frame), and then a target reverberation gain parameter is determined by using the relationship between both the first difference value and the second difference value obtained by the smoothing process and the preset threshold value.

[0139] In some cases, in one embodiment, the step of determining target reverberation gain parameters that need to be encoded in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes the steps of determining energies of N subbands of the downmix signal; determining M subbands from the N subbands, wherein the energy of any subband among the M subbands is greater than the energy of any subband among NM subbands within the N subbands excluding the M subbands, where both M and N are integers greater than 0 and M is less than N; and determining the target reverberation gain parameters based on a magnitude relationship between the energies of the M subbands and the energies of the NM subbands.

[0140] The coherence between the first channel signal and the second channel signal can be determined based on the energy of different subbands of the downmix signal, and further, the target reverberation gain parameter that needs to be encoded is determined based on the coherence between the first channel signal and the second channel signal.

[0141] Specifically, the step of determining the target reverberation gain parameter based on the magnitude relationship between the energies of the M subbands of the downmix signal and the energies of the NM subbands of the downmix signal includes the step of determining that the reverberation gain parameter corresponding to the subbands of the first frequency band of the first channel signal and the second channel signal is the target reverberation gain parameter when the sum of the energies of the M subbands is greater than K times the sum of the energies of the NM subbands, where K is a real number greater than 0.

[0142] The step of determining the target reverberation gain parameters based on the magnitude relationship between the energies of the M subbands of the downmix signal and the energies of the NM subbands of the downmix signal includes the step of determining that the reverberation gain parameters corresponding to the subbands of the first frequency band of the first channel signal and the second channel signal are the target reverberation gain parameters when an average value of the energies of the M subbands is greater than L times the average value of the energies of the NM subbands, where L is a real number greater than 0.

[0143] It is understood that K and L may have different values. More specifically, when M is greater than NM, K may be less than L, and when M is less than NM, K may be greater than L.

[0144] The energies of the N subbands of the downmix signal and the energies of the NM subbands of the downmix signal may be compared by comparing the average value of the energies of the M subbands of the downmix signal with the average value of the energies of the NM subbands of the downmix signal. To further reduce the complexity of the calculation, the sum of the energies of the M subbands of the downmix signal and the sum of the energies of the NM subbands of the downmix signal may be directly compared. In this way, the calculation process is simplified to a certain extent and efficiency is improved.

[0145] When the difference between the energy of M subbands having relatively large energy and the energy of another subband having relatively small energy in the downmix signal is relatively large, the difference between the first channel signal and the second channel signal may be considered to be relatively large. In this case, reverberation gain parameters corresponding to subbands of some frequency bands in the first channel signal and the second channel signal may be determined as the target reverberation gain parameters to be encoded. Specifically, the first frequency band may be a frequency band in a low frequency part of the first channel signal and the second channel signal, or may be a frequency band in a mid-frequency part of the first channel signal and the second channel signal.

[0146] In some cases, in one embodiment, the step of determining target reverberation gain parameters to be encoded in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes the steps of: determining energies of N subbands of the downmix signal; determining M subbands from the N subbands, where the energy of any subband among the M subbands is greater than the energy of any subband among the N subbands excluding the M subbands; and determining, when an index value of a first subband among the M subbands is smaller than a preset index value, that the reverberation gain parameters corresponding to subbands of a first frequency band of the first channel signal and the second channel signal are the target reverberation gain parameters, where the frequency of any frequency bin of the first subband is greater than the frequency of any frequency bin of another subband among the M subbands excluding the first subband, and the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0147] When the index value of the subband with the highest frequency among the M subbands having relatively large energy is smaller than the preset index value, it can be considered that the energy distribution of the M subbands of the downmix signal is uneven, that is, the coherence between the first channel signal and the second channel signal is relatively small. In this case, only the reverberation gain parameters corresponding to the subbands of some frequency bands need to be coded.

[0148] The downmix signal may be a wideband signal or an ultra-wideband signal. When the downmix signal is a wideband signal, the N subbands may be all subbands of the downmix signal, and when the downmix signal is an ultra-wideband signal, the N subbands may be subbands of the downmix signal in the wideband part.

[0149] The M subbands may be determined from the N subbands based on the amplitude of each subband of the downmix signal in addition to the magnitude of the energy of each subband of the downmix signal. Specifically, the M subbands may be determined based on the amplitude of each subband of the downmix signal such that the amplitude of any subband among the M subbands is greater than the amplitude of any subband among the NM subbands.

[0150] The value of M may be a preset value before encoding. For example, the downmix signal includes a total of 10 subbands. In this case, four subbands with the largest energy or amplitude may be selected. When the energy or amplitude values ​​(which may be the sum or average of the energy or amplitude values) of the four subbands of the downmix signal are greater than a predetermined multiple of the energy or amplitude values ​​of the remaining six subbands of the downmix signal, the reverberation gain parameters corresponding to the first frequency bands of the first channel signal and the second channel signal are determined to be target reverberation gain parameters.

[0151] It should be understood that in this embodiment of the present application, the target reverberation gain parameters may be determined based on at least one of the following conditions: When at least one of the following conditions is valid, some reverberation gain parameters may be determined as the target reverberation gain parameters:

[0152] Condition 1: One or more difference values ​​between the energy of the first channel signal and / or the energy of the second channel signal and the energy of the downmix signal are greater than one or more preset thresholds.

[0153] Condition 2: The energy of the M subbands of the downmix signal is greater than a predetermined multiple of the energy of the NM subbands of the downmix signal.

[0154] Condition 3: The index value of the first subband among the M subbands is greater than the preset index value.

[0155] The frequency of any spectral coefficient in the first subband is greater than the frequency of any spectral coefficient in another subband among the M subbands excluding the first subband.

[0156] In some cases, in one embodiment, the step of determining target reverberation gain parameters to be encoded in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal includes the steps of determining energies of N subbands of the downmix signal, determining J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, both N and J are integers greater than 0, and J is less than N, and determining the reverberation gain parameters corresponding to the J target subbands as the target reverberation gain parameters, where J may be a predetermined number.

[0157] Based on the energy of each subband of the downmix signal, a predetermined number of subbands are directly selected from all subbands, and the reverberation gain parameters corresponding to the predetermined number of subbands are determined as target reverberation gain parameters, so that the reverberation gain parameters that need to be encoded can be selected more flexibly.

[0158] Compared with the method of determining a reverberation gain parameter corresponding to a subband of a fixed frequency band as a target reverberation gain parameter, the present invention allows direct and flexible selection of a reverberation gain parameter corresponding to several subbands that may not be adjacent in the frequency domain as a target reverberation gain parameter.

[0159] In some cases, in one embodiment, the energy of the downmix signal is determined based on the energy of the first channel signal and the energy of the second channel signal. The energy of the downmix signal may be calculated based on the downmix signal itself, or may be estimated or inferred using the energy of the first channel signal and the energy of the second channel signal. When the energy of the downmix signal is determined using the energy of the first channel signal and the energy of the second channel signal, the calculation process can be simplified to some extent.

[0160] Fig. 4 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application. The method of Fig. 4 may be performed by a decoder-side device or a decoder. The decoding method of Fig. 4 corresponds to the encoding method of Fig. 3. The decoding method of Fig. 4 may be used to decode a bitstream obtained by encoding a first channel signal and a second channel signal in the encoding method of Fig. 3. The method of Fig. 4 includes the following steps:

[0161] 410. Receive a bitstream.

[0162] 420. Based on the bitstream, obtain a downmix signal of a first channel signal and a second channel signal in the multi-channel signal, and parameter indication information, where the parameter indication information is used to indicate encoded target reverberation gain parameters in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal.

[0163] The parameter indication information can indicate subbands corresponding to target reverberation gain parameters by using flag bits. For example, each of the first and second channel signals includes 10 subbands (subbands with index numbers 0 to 9), and the parameter indication information includes 10 flag bits, which consecutively correspond to the 10 subbands of each multi-channel signal. When the flag bit corresponding to a subband is 1, the reverberation gain parameter corresponding to the subband is the target reverberation gain parameter that needs to be encoded. When the flag bit corresponding to a subband is 0, the reverberation gain parameter corresponding to the subband is not the target reverberation gain parameter. Specifically, when the flag bit corresponding to subbands with index numbers 0 to 5 is 1 and the flag bit corresponding to subbands with index numbers 6 to 9 is 0, the decoder side decodes only the reverberation gain parameters corresponding to the subbands with index numbers 1 to 5 during decoding.

[0164] 430. Obtain the target reverberation gain parameters from the bitstream according to the parameter indication information.

[0165] 440. Determine a first channel signal and a second channel signal based on the downmix signal and the target reverberation gain parameter.

[0166] In the present application, the target reverberation gain parameters encoded by the encoder can be determined using the parameter indication information, and then reverberation processing is performed on the corresponding subbands of the first channel signal and the second channel signal based on the target reverberation gain parameters.

[0167] It should be understood that before reverberation processing is performed on the first channel signal and the second channel signal based on the target reverberation gain parameter, the decoder side further obtains a decoherence signal and corrects the decoherence signal using the target reverberation gain parameter. Then, reverberation processing may be further performed on the first channel signal and the second channel signal using the corrected decoherence signal. If each of the first channel signal and the second channel signal includes 10 subbands (subbands with index numbers 0 to 9) and the reverberation gain parameters corresponding to the subbands with index numbers 0 to 5 are the target reverberation gain parameters, the decoder side only obtains the reverberation gain parameters corresponding to the subbands with index numbers 0 to 5, but does not obtain the reverberation gain parameters corresponding to the subbands with index numbers 6 to 10. Therefore, the decoder side performs reverberation processing only on the subbands with index numbers 0 to 5 of the first channel signal and the second channel signal, but does not perform reverberation processing on the subbands with index numbers 6 to 10 of the first channel signal and the second channel signal.

[0168] When the first channel signal and the second channel signal include a left channel signal and a right channel signal, determining the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameter includes determining a decoherence signal based on the downmix signal and the target reverberation gain parameter of a frame previous to the current frame, and determining the left channel signal and the right channel signal based on the decoherence signal and the downmix signal of the current frame.

[0169] For example, the first channel signal and the second channel signal include a left channel signal and a right channel signal. The downmix signal of the current frame is dmx, the downmix signal of the frame preceding the current frame is dmx_pred, and the target downmix gain parameter is gain. Then, a decoherence signal tmp is first obtained based on dmx_pred and gain. Then, a left channel signal L=dmx+tmp and a right channel signal R=dmx-tmp are obtained based on the downmix signal of the current frame and the decoherence signal.

[0170] With reference to FIG. 5 and FIG. 6, the following describes in detail the entire process of the encoding method and decoding method for multi-channel signals in the embodiment of the present application by using an example of a left channel signal and a right channel signal.

[0171] 5 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application. In FIG. 5, the multi-channel signal includes a left channel signal and a right channel signal, and the process of encoding the left channel signal and the right channel signal specifically includes the following steps:

[0172] 510. Calculate spatial parameters of the left channel signal and spatial parameters of the right channel signal.

[0173] The spatial parameters include reverberation gain parameters corresponding to the subbands of the left and right channel signals, as well as other spatial parameters (such as IC, ILD, ITD, and IPD).

[0174] 520. Perform a downmixing process on the left channel signal (represented by L in the figure) and the right channel signal (represented by R in the figure) to obtain a downmix signal.

[0175] 530. Adaptively select target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the subbands of the left channel signal and the right channel signal.

[0176] 540. The target reverberation gain parameter and the downmix signal are separately quantized to obtain a bitstream.

[0177] Figure 6 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application. In Figure 6, the multi-channel signal includes a left channel signal and a right channel signal. The bitstream generated by the encoding in Figure 5 can be decoded in Figure 6. The decoding process in Figure 6 specifically includes the following steps:

[0178] 610. Obtain a bit stream of a left channel signal and a right channel signal.

[0179] 620. The bitstream is decoded to obtain a downmix signal.

[0180] 630. Obtain flag information in the bitstream, and determine the target reverberation gain parameter that needs to be decoded based on the flag bits of the flag information.

[0181] 640. Decode the left and right channel signals and reverberation gain parameters corresponding to the subbands for reverberation processing among other spatial parameters (such as IC, ILD, ITD, and IPD).

[0182] 640. Perform subsequent processing (e.g., smoothing filtering) on ​​the spatial parameters obtained by decoding.

[0183] 650. Perform an upmixing process based on the downmix signal obtained by decoding and the reverberation gain parameter to obtain a left channel signal and a right channel signal.

[0184] After the upmixing process is performed to obtain the left channel signal and the right channel signal, reverberation processing may be performed separately on the left channel signal and the right channel signal based on the coherence signal.

[0185] In the method shown in FIG. 6, reverberation processing is performed on the left channel signal and the right channel signal based on the target reverberation gain parameter obtained by decoding, and reverberation processing may be performed on some subbands of the left channel signal and the right channel signal based on the target reverberation gain parameter, thereby ensuring the quality of the channel signals obtained after the reverberation processing.

[0186] 7 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application. The method of FIG. 7 may be performed by an encoder-side device or an encoder. The method of FIG. 7 includes the following steps:

[0187] 710. Determine a downmix signal of the first channel signal and the second channel signal in the multi-channel signal, and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal.

[0188] The present application does not impose any restrictions on the order between the process of generating a downmix signal and the process of generating reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, and the processes may be performed simultaneously or sequentially.

[0189] Specifically, the downmix signal may be obtained by performing a downmixing process on the first channel signal and the second channel signal. A spatial parameter analysis is performed on the first channel signal and the second channel signal to obtain spatial parameters of the first channel signal and the second channel signal. The spatial parameters include reverberation gain parameters corresponding to each subband of the first channel signal and the second channel signal, as well as IC, ILD, ITD, IPD, etc. between the first channel signal and the second channel signal.

[0190] 720. Determine target reverberation gain parameters that need to be encoded within reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of the N subbands of the downmix signal, where N is an integer greater than 0.

[0191] The energies of the subbands of the downmix signal may be calculated based on the downmix signal itself, or the energy of the downmix signal may be estimated or inferred using the energy of the first channel signal and the energy of the second channel signal. When the energy of the downmix signal is determined using the energy of the first channel signal and the energy of the second channel signal, the calculation process can be simplified to some extent.

[0192] Specifically, J target subbands may be determined from the N subbands based on the energies of the N subbands of the downmix signal, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N. The reverberation gain parameters corresponding to the J target subbands are determined as target reverberation gain parameters.

[0193] Based on the energy of each subband of the downmix signal, a predetermined number of subbands are directly selected from all subbands, and the reverberation gain parameters corresponding to the predetermined number of subbands are determined as target reverberation gain parameters, so that the reverberation gain parameters that need to be encoded can be selected more flexibly.

[0194] 730. Encode the downmix signal and the target reverberation gain parameter.

[0195] In addition, the downmix signal may be a wideband signal or an ultra-wideband signal. When the downmix signal is a wideband signal, the multiple subbands may be all subbands of the downmix signal, and when the downmix signal is an ultra-wideband signal, the multiple subbands may be subbands of the downmix signal in the wideband part.

[0196] In the present application, a certain number of subbands are directly selected from all subbands based on the energy of each subband of the downmix signal, so that the reverberation gain parameters to be coded can be selected more flexibly. In addition, compared with the method of determining the reverberation gain parameters corresponding to subbands of a fixed frequency band as the target reverberation gain parameters, the reverberation gain parameters corresponding to some subbands that may not be adjacent in the frequency domain can be directly selected as the target reverberation gain parameters.

[0197] Figure 8 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application. The method of Figure 8 may be performed by a decoder-side device or a decoder. The decoding method of Figure 8 corresponds to the encoding method of Figure 7. The decoding method of Figure 8 may be used to decode a bitstream obtained by encoding a first channel signal and a second channel signal in the encoding method of Figure 7. The method of Figure 8 includes the following steps:

[0198] 810. Receive a bitstream.

[0199] 820. Obtain a downmix signal of the first channel signal and the second channel signal in the multi-channel signal based on the bitstream.

[0200] Specifically, the bitstreams of the first channel signal and the second channel signal may be demultiplexed first, and then the bitstream corresponding to the downmix signal may be decoded to obtain the downmix signal.

[0201] 830. Determine encoded target reverberation gain parameters within the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of the N subbands of the downmix signal, where N is an integer greater than 0.

[0202] Specifically, J target subbands may be determined from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, where both N and J are integers greater than 0, and J is less than N. The reverberation gain parameters corresponding to the J target subbands are determined as target reverberation gain parameters.

[0203] It should be understood that both the encoder side and the decoder side can determine the encoded target reverberation gain parameters in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal according to the same rule based on the energies of multiple subbands of the downmix signal. In this way, the encoder side does not need to indicate the encoded reverberation gain parameters in the bitstream, and the decoder side can determine the encoded reverberation gain parameters using the same rule.

[0204] For example, the encoder side determines, based on the energies of multiple subbands of the downmix signal, that the reverberation gain parameters corresponding to the subbands with index numbers 0 to 5 are target reverberation gain parameters, quantizes the reverberation gain parameters corresponding to the subbands with index numbers 0 to 5, writes the quantized reverberation gain parameters into a bitstream, and transmits the bitstream to the decoder side. After receiving the bitstream, the decoder side similarly determines, based on the energies of multiple subbands of the downmix signal, that the reverberation gain parameters corresponding to the subbands with index numbers 0 to 5 are target reverberation gain parameters, and then decodes the reverberation gain parameters corresponding to the subbands with index numbers 0 to 5.

[0205] 840. Determine a target reverberation gain parameter based on the bitstream.

[0206] In addition to the target reverberation gain parameter, other spatial parameters coded at the encoder side, such as IC, ILD, ITD, and IPD, may be obtained from the bitstream.

[0207] 850. Determine a first channel signal and a second channel signal based on the downmix signal and the target reverberation gain parameter.

[0208] In the present application, the decoder side can directly determine the encoded target reverberation gain parameters in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of multiple subbands of the downmix signal, so that the bits occupied by the decoder side for transmitting the indication information indicating the encoded target reverberation gain parameters can be reduced, and the signaling overhead can be reduced to a certain extent.

[0209] Specifically, before performing reverberation processing on the first channel signal and the second channel signal based on the target reverberation gain parameter, the decoder side further obtains a decoherence signal and corrects the decoherence signal using the target reverberation gain parameter (the decoherence signal may be obtained by delaying a downmix signal). Then, the decoder side may further perform reverberation processing on the first channel signal and the second channel signal using the corrected decoherence signal. If each of the first channel signal and the second channel signal includes 10 subbands and the reverberation gain parameters corresponding to the subbands with index numbers 1, 3, 5, and 7 are the target reverberation gain parameters, the decoder side only obtains reverberation gain parameters corresponding to the subbands with index numbers 1, 3, 5, and 7, and does not obtain reverberation gain parameters corresponding to the subbands with index numbers 2, 4, 6, 8, 9, and 10. Therefore, the decoder side performs reverberation processing only on the subbands whose index numbers of the first and second channel signals are 1, 3, 5, and 7, and does not perform reverberation processing on the subbands whose index numbers of the first and second channel signals are 2, 4, 6, 8, 9, and 10.

[0210] When the first channel signal and the second channel signal include a left channel signal and a right channel signal, determining the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameter includes determining a decoherence signal based on the downmix signal and the target reverberation gain parameter of a frame previous to the current frame, and determining the left channel signal and the right channel signal based on the decoherence signal and the downmix signal of the current frame.

[0211] With reference to FIG. 9 and FIG. 10, the following describes in detail the entire process of the encoding method and decoding method for multi-channel signals in the embodiment of the present application by using an example of a left channel signal and a right channel signal.

[0212] 9 is a schematic flowchart of a multi-channel signal encoding method according to an embodiment of the present application. In FIG. 9, the multi-channel signal includes a left channel signal and a right channel signal, and the process of encoding the left channel signal and the right channel signal specifically includes the following steps:

[0213] 910. Calculate spatial parameters of the left channel signal and spatial parameters of the right channel signal.

[0214] The spatial parameters include reverberation gain parameters corresponding to the subbands of the left and right channel signals, as well as other spatial parameters (such as IC, ILD, ITD, and IPD).

[0215] 920. Perform a downmixing process on the left channel signal (represented by L in the figure) and the right channel signal (represented by R in the figure) to obtain a downmix signal.

[0216] 930. Determine the energies of different subbands of the downmix signal.

[0217] The energy of the downmix signal may be calculated based on the downmix signal itself, or may be estimated or inferred based on the energy of the first channel signal and the energy of the second channel signal.

[0218] 940. Adaptively select target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the subbands of the left channel signal and the right channel signal based on the energy of different subbands of the downmix signal.

[0219] 950. Quantize the target reverberation gain parameters and the downmix signal to obtain a bitstream.

[0220] Figure 10 is a schematic flowchart of a multi-channel signal decoding method according to an embodiment of the present application. In Figure 10, the multi-channel signal includes a left channel signal and a right channel signal. The bitstream generated by the encoding in Figure 9 can be decoded in Figure 10. The decoding process in Figure 10 specifically includes the following steps:

[0221] 1010. Obtain a bit stream of a left channel signal and a right channel signal.

[0222] 1020. Decode the bitstream to obtain a downmix signal.

[0223] 1030. Determine the energy of different subbands of the downmix signal.

[0224] The energy of the downmix signal may be calculated based on the downmix signal itself, or may be estimated or inferred based on the energy of the first channel signal and the energy of the second channel signal.

[0225] 1040. Adaptively select subbands of the left channel signal and the right channel signal for reverberation processing based on the energy of different subbands of the downmix signal.

[0226] 1050. Decode reverberation gain parameters and other spatial parameters (such as IC, ILD, ITD, and IPD) corresponding to the selected subbands for reverberation processing of the left and right channel signals.

[0227] 1060. To obtain a left channel signal and a right channel signal, perform an upmixing process based on the downmix signal obtained by decoding and a reverberation gain parameter (the reverberation gain parameter is the reverberation gain parameter adjusted by the encoder side).

[0228] After the upmixing process is performed to obtain the left channel signal and the right channel signal, reverberation processing may be performed separately on the left channel signal and the right channel signal based on the coherence signal.

[0229] In the method shown in FIG. 10 , reverberation processing is performed on the left channel signal and the right channel signal based on the target reverberation gain parameter obtained by decoding, and reverberation processing may be performed on some subbands of the left channel signal and the right channel signal based on the target reverberation gain parameter, thereby ensuring the quality of the channel signal obtained after the reverberation processing.

[0230] The above describes in detail the multi-channel signal encoding method and the multi-channel signal decoding method in the embodiment of the present application with reference to Figures 3 to 10. Hereinafter, the encoder and decoder in the embodiment of the present application will be described with reference to Figures 11 to 18. It should be understood that the encoder and decoder in Figures 11 to 18 can implement the steps performed by the encoder and decoder in the encoding method and decoding method in the embodiment of the present application. For the sake of brevity, repeated descriptions will be omitted below as appropriate.

[0231] 11 is a schematic block diagram of an encoder according to one embodiment of the present application. The encoder 1100 of FIG. a processing unit 1110 configured to determine a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, the processing unit 1110 is further configured to determine target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; a processing unit 1110 further configured to generate parameter indication information, the parameter indication information being used to indicate a subband corresponding to a target reverberation gain parameter; an encoding unit 1120 configured to encode the target reverberation gain parameters, the parameter indication information, and the downmix signal to generate a bitstream; Includes:

[0232] In the present application, when the first channel signal and the second channel signal are encoded, reverberation gain parameters corresponding to only some subbands of the first channel signal and the second channel signal may be encoded. Compared with the prior art scheme in which reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal need to be encoded, bit overhead can be reduced to a certain extent and coding efficiency can be improved. Specifically, when reverberation gain parameters corresponding to some subbands are encoded, a large amount of saved bits can be used to code other parameters or allocate more bits to the downmix signal, thereby improving overall coding performance.

[0233] The encoder 1100 may correspond to and perform the multi-channel signal encoding method of FIG.

[0234] In some cases, in one embodiment, the processing unit 1110 is specifically configured to determine the target reverberation gain parameter based on at least one of a coherence between the energy of the first channel signal and the energy of the downmix signal, and a coherence between the energy of the second channel signal and the energy of the downmix signal.

[0235] In some cases, in one embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the processing unit 1110 is specifically configured to: determine a first difference value between the energy of the first channel signal and the energy of the downmix signal, where the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the downmix signal in a plurality of frequency bins; and determine, when the first difference value is greater than a first threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is a target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0236] In some cases, in one embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the processing unit 1110 is specifically configured to: determine a second difference value between the energy of the second channel signal and the energy of the downmix signal, where the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the downmix signal in a plurality of frequency bins; and determine, when the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is a target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0237] In some cases, in one embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the processing unit 1110 is specifically configured to: determine a first difference value between the energy of the first channel signal and the energy of the down-mix signal, where the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the down-mix signal in a plurality of frequency bins; determine a second difference value between the energy of the second channel signal and the energy of the down-mix signal, where the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the down-mix signal in a plurality of frequency bins; and determine, when the first difference value is greater than a first threshold and the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a sub-band of the first frequency band is a target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0238] Optionally, in one embodiment, the frequency of the first frequency band is less than the frequency of another frequency band different from the first frequency band in the first channel signal and the second channel signal.

[0239] In some cases, in one embodiment, the plurality of frequency bins are within a second frequency band of each of the first channel signal and the second channel signal, and the frequency of the second frequency band is greater than the frequency of another frequency band different from the second frequency band in the first channel signal and the second channel signal.

[0240] In some cases, in one embodiment, the processing unit 1110 is specifically configured to: determine energies of N subbands of the downmix signal; determine M subbands from the N subbands, where the energy of any subband among the M subbands is greater than the energy of any subband among the NM subbands in the N subbands excluding the M subbands, where both M and N are integers greater than 0 and M is less than N; and determine a target reverberation gain parameter based on a magnitude relationship between the energies of the M subbands of the downmix signal and the energies of the NM subbands of the downmix signal.

[0241] In some cases, in one embodiment, the processing unit 1110 is specifically configured to determine that the reverberation gain parameters corresponding to the subbands of the first frequency band of the first channel signal and the second channel signal are the target reverberation gain parameters when the sum of the energies of the M subbands is greater than L times the sum of the energies of the NM subbands, where the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal, and L is a real number greater than 0.

[0242] In some cases, in one embodiment, the processing unit 1110 is specifically configured to: determine energies of N subbands of the downmix signal; determine M subbands from the N subbands, where the energy of any subband among the M subbands is greater than the energy of any subband among the NM subbands in the N subbands excluding the M subbands; and determine, when an index value of a first subband among the M subbands is smaller than a preset index value, a reverberation gain parameter corresponding to a subband of a first frequency band of the first channel signal and the second channel signal is a target reverberation gain parameter, where a frequency of any frequency bin in the first subband is greater than a frequency of any frequency bin in another subband among the M subbands excluding the first subband, and the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0243] In some cases, in one embodiment, the processing unit 1110 is specifically configured to: determine J target subbands from the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; and determine reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters.

[0244] Optionally, in one embodiment, the energy of the downmix signal is determined based on the energy of the first channel signal and the energy of the second channel signal.

[0245] 12 is a schematic block diagram of a decoder according to one embodiment of the present application. The decoder 1200 of FIG. an acquisition unit 1210 configured to receive a bitstream, the obtaining unit 1210 is further configured to obtain, based on the bitstream, a downmix signal of a first channel signal and a second channel signal in the multi-channel signal, and parameter indication information, wherein the parameter indication information is used to indicate encoded target reverberation gain parameters in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; an obtaining unit 1210, wherein the obtaining unit 1210 is further configured to obtain a target reverberation gain parameter from the bitstream according to the parameter indication information; a processing unit 1220 configured to determine a first channel signal and a second channel signal based on the downmix signal and a target reverberation gain parameter; Includes:

[0246] In the present application, the target reverberation gain parameters encoded by the encoder can be determined using the parameter indication information, and then reverberation processing is performed on the corresponding subbands of the first channel signal and the second channel signal based on the target reverberation gain parameters.

[0247] The encoder 1200 may correspond to the multi-channel signal decoding method of FIG. 4, and the decoder 1200 may perform the multi-channel signal decoding method of FIG.

[0248] 13 is a schematic block diagram of an encoder according to an embodiment of the present application. The encoder 1300 of FIG. a processing unit 1310 configured to determine a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, The processing unit 1310 is further configured to determine, based on the energies of the N subbands of the downmix signal, target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, where N is an integer greater than 0; an encoding unit 1320 configured to encode the downmix signal and the target reverberation gain parameter; Includes:

[0249] In this application, a certain number of subbands are directly selected from all subbands based on the energy of each subband of the downmix signal, which results in more flexibility in selecting the reverberation gain parameters that need to be coded.

[0250] The encoder 1300 may correspond to and perform the channel signal encoding method of FIG.

[0251] In some cases, in one embodiment, the processing unit 1310 is specifically configured to: determine J target subbands from the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; and determine reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters.

[0252] 14 is a schematic block diagram of a decoder according to one embodiment of the present application. The decoder 1400 of FIG. a first acquisition unit 1410 configured to receive a bitstream; a first processing unit 1420 configured to determine a downmix signal of a first channel signal and a second channel signal in the multi-channel signal based on the bitstream; a second processing unit 1430 configured to determine encoded target reverberation gain parameters among the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on energies of the N subbands of the downmix signal, where N is an integer greater than 0; a third processing unit 1440 configured to determine a target reverberation gain parameter based on the bitstream; a fourth processing unit 1450 configured to determine a first channel signal and a second channel signal based on the downmix signal and a target reverberation gain parameter; Includes:

[0253] In the present application, the decoder side can directly determine the encoded target reverberation gain parameters in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of multiple subbands of the downmix signal, so that the bits occupied by the decoder side for transmitting the indication information indicating the encoded target reverberation gain parameters can be reduced, and the signaling overhead can be reduced to a certain extent.

[0254] The decoder 1400 may correspond to the multi-channel signal decoding method of FIG. 8, and the decoder 1400 may perform the multi-channel signal decoding method of FIG.

[0255] In some cases, in one embodiment, the first processing unit 1430 is specifically configured to: determine J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, where both N and J are integers greater than 0, and J is less than N; and determine reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters.

[0256] 15 is a schematic block diagram of an encoder according to one embodiment of the present application. The encoder 1500 of FIG. a memory 1510 configured to store a program; a processor 1520 configured to execute a program, the processor 1520 being configured, when the program is executed, to: determine reverberation gain parameters corresponding to a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and different subbands of the first channel signal and the second channel signal; determine target reverberation gain parameters to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal; generate parameter indication information, the parameter indication information being used to indicate the subbands corresponding to the target reverberation gain parameters; and encode the target reverberation gain parameters, the parameter indication information, and the downmix signal to generate a bitstream; Includes:

[0257] In the present application, when the first channel signal and the second channel signal are encoded, reverberation gain parameters corresponding to only some subbands of the first channel signal and the second channel signal may be encoded. Compared with the prior art scheme in which reverberation gain parameters corresponding to all subbands of the first channel signal and the second channel signal need to be encoded, bit overhead can be reduced to a certain extent and coding efficiency can be improved. Specifically, when reverberation gain parameters corresponding to some subbands are encoded, a large amount of saved bits can be used to code other parameters or allocate more bits to the downmix signal, thereby improving overall coding performance.

[0258] The encoder 1500 may correspond to and perform the channel signal encoding method of FIG.

[0259] In some cases, in one embodiment, the processor 1520 is configured to specifically determine the target reverberation gain parameter based on at least one of a coherence between the energy of the first channel signal and the energy of the downmix signal, and a coherence between the energy of the second channel signal and the energy of the downmix signal.

[0260] In some cases, in one embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the processor 1520 is specifically configured to: determine a first difference value between the energy of the first channel signal and the energy of the downmix signal, where the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the downmix signal in the plurality of frequency bins; and determine, when the first difference value is greater than a first threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is a target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0261] In some cases, in one embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the processor 1520 is specifically configured to: determine a second difference value between the energy of the second channel signal and the energy of the downmix signal, where the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the downmix signal in the plurality of frequency bins; and determine, when the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of the first frequency band is a target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0262] In some cases, in one embodiment, each of the first channel signal and the second channel signal includes a plurality of frequency bins, and the processor 1520 is specifically configured to: determine a first difference value between the energy of the first channel signal and the energy of the down-mix signal, where the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the down-mix signal in the plurality of frequency bins; determine a second difference value between the energy of the second channel signal and the energy of the down-mix signal, where the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the down-mix signal in the plurality of frequency bins; and determine, when the first difference value is greater than a first threshold and the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a sub-band of the first frequency band is a target reverberation gain parameter, where the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0263] Optionally, in one embodiment, the frequency of the first frequency band is less than the frequency of another frequency band different from the first frequency band in the first channel signal and the second channel signal.

[0264] In some cases, in one embodiment, the plurality of frequency bins are within a second frequency band of each of the first channel signal and the second channel signal, and the frequency of the second frequency band is greater than the frequency of another frequency band different from the second frequency band in the first channel signal and the second channel signal.

[0265] In some cases, in one embodiment, the processor 1520 is specifically configured to: determine energies of N subbands of the downmix signal; determine M subbands from the N subbands, wherein the energy of any subband among the M subbands is greater than the energy of any subband among the NM subbands within the N subbands excluding the M subbands, where both M and N are integers greater than 0 and M is less than N; and determine a target reverberation gain parameter based on a magnitude relationship between the energies of the M subbands and the energies of the NM subbands.

[0266] In some cases, in one embodiment, the processor 1520 is specifically configured to determine that the reverberation gain parameters corresponding to the subbands of the first frequency band of the first channel signal and the second channel signal are the target reverberation gain parameters when the sum of the energies of the M subbands is greater than L times the sum of the energies of the NM subbands, where the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal, and L is a real number greater than 0.

[0267] In some cases, in one embodiment, the processor 1520 is specifically configured to: determine energies of N subbands of the downmix signal; determine M subbands from the N subbands, wherein the energy of any subband among the M subbands is greater than the energy of any subband among the NM subbands in the N subbands excluding the M subbands; and determine, when an index value of a first subband among the M subbands is smaller than a preset index value, a reverberation gain parameter corresponding to a subband of a first frequency band of the first channel signal and the second channel signal is a target reverberation gain parameter, wherein a frequency of any frequency bin in the first subband is greater than a frequency of any frequency bin in another subband among the M subbands excluding the first subband, and the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal.

[0268] In some cases, in one embodiment, the processor 1520 is specifically configured to: determine energies of N subbands of the downmix signal; determine J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, both N and J are integers greater than 0, and J is less than N; and determine reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters.

[0269] Optionally, in one embodiment, the energy of the downmix signal is determined based on the energy of the first channel signal and the energy of the second channel signal.

[0270] 16 is a schematic block diagram of a decoder according to one embodiment of the present application. The decoder 1600 of FIG. a memory 1610 configured to store a program; a processor 1620 configured to execute a program, the processor 1620 being configured, when the program is executed, to: receive a bitstream; obtain, based on the bitstream, a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and parameter indication information, the parameter indication information being used to indicate encoded target reverberation gain parameters in reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; obtain the target reverberation gain parameters from the bitstream according to the parameter indication information; and determine the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameters; Includes:

[0271] In the present application, the target reverberation gain parameters encoded by the encoder can be determined using the parameter indication information, and then reverberation processing is performed on the corresponding subbands of the first channel signal and the second channel signal based on the target reverberation gain parameters.

[0272] The decoder 1600 may correspond to the multi-channel signal decoding method of FIG. 4, and the decoder 1600 may perform the multi-channel signal decoding method of FIG.

[0273] 17 is a schematic block diagram of an encoder according to an embodiment of the present application. The encoder 1700 of FIG. a memory 1710 configured to store a program; a processor 1720 configured to execute a program, the processor 1720 being configured, when the program is executed, to: determine a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; determine target reverberation gain parameters to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal based on energies of N subbands of the downmix signal, where N is an integer greater than 0; and encode the downmix signal and the target reverberation gain parameters; Includes:

[0274] In this application, a certain number of subbands are directly selected from all subbands based on the energy of each subband of the downmix signal, which results in more flexibility in selecting the reverberation gain parameters that need to be coded.

[0275] The encoder 1700 may correspond to, and may perform, the channel signal encoding method of FIG.

[0276] In some cases, in one embodiment, the processor 1720 is specifically configured to: determine J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; and determine reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters.

[0277] 18 is a schematic block diagram of a decoder according to one embodiment of the present application. The decoder 1800 of FIG. a memory 1810 configured to store a program; a processor 1820 configured to execute a program, the processor 1820 being configured, when the program is executed, to: receive a bitstream; determine a downmix signal of a first channel signal and a second channel signal in a multi-channel signal based on the bitstream; determine encoded target reverberation gain parameters among the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on energies of N subbands of the downmix signal, where N is an integer greater than 0; determine the target reverberation gain parameters based on the bitstream; and determine the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameters; Includes:

[0278] In the present application, the decoder side can directly determine the encoded target reverberation gain parameters in the reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on the energies of multiple subbands of the downmix signal, so that the bits occupied by the decoder side for transmitting the indication information indicating the encoded target reverberation gain parameters can be reduced, and the signaling overhead can be reduced to a certain extent.

[0279] The decoder 1800 may correspond to the multi-channel signal decoding method of FIG. 8, and the decoder 1800 may perform the multi-channel signal decoding method of FIG.

[0280] In some cases, in one embodiment, the processor 1820 is specifically configured to: determine J target subbands from the N subbands based on the energies of the N subbands, where the energy of any subband among the J target subbands is greater than the energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; and determine reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters.

[0281] In combination with the examples described in the embodiments disclosed herein, those skilled in the art will recognize that the units and algorithm steps may be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether a function is performed by hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use various methods to implement the described functions for each specific application, but the implementation form should not be considered to go beyond the scope of this application.

[0282] For convenient and concise description, those skilled in the art will clearly understand that for the detailed operation processes of the above systems, devices and units, please refer to the corresponding processes in the above method embodiments, and the details will not be described again in this specification.

[0283] In some embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the described device embodiments are merely examples. For example, the unit division is merely a logical functional division, and other divisions may be used in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some functions may be ignored or not performed. In addition, the shown or described mutual couplings or direct couplings or communication connections may be implemented by using some interfaces. Indirect couplings or communication connections between devices or units may be implemented in electrical, mechanical, or other forms.

[0284] The units described as separate parts may or may not be physically separated, and the parts shown as units may or may not be physical units, and may be located in one location or distributed over multiple network units. Some or all of the units may be selected based on actual requirements to achieve the objectives of the solutions of the embodiments.

[0285] In addition, the functional units in the embodiments of the present application may be integrated into one processing unit, or each of the units may exist physically alone, or two or more units may be integrated into one unit.

[0286] When a function is implemented in the form of a software functional unit and sold or used as an independent product, the function may be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application may essentially, or a portion contributing to the prior art, or a portion of the technical solution may be implemented in the form of a software product. A computer software product is stored in a storage medium and includes some instructions for instructing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or some of the steps of the methods described in the embodiments of the present application. The aforementioned storage medium includes any medium capable of storing program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0287] The above description is merely a specific implementation form of the present application and does not limit the scope of protection of the present application. Any variations or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should fall within the scope of protection of the present application. Therefore, the scope of protection of the present application should be subject to the scope of protection of the claims. [Explanation of symbols]

[0288] 1100 Encoder 1110 Processing Unit 1120 coding units 1200 decoder 1210 Acquisition Units 1220 Processing Unit 1300 Encoder 1310 Processing Unit 1320 coding units 1400 decoder 1410 First Acquisition Unit 1420 first processing unit 1430 second processing unit 1440 Third Processing Unit 1450 4th Processing Unit 1500 Encoder 1510 memory 1520 processor 1600 decoder 1610 memory 1620 processor 1700 Encoder 1710 memory 1720 processor 1800 decoder 1810 memory 1820 processor

Claims

1. 1. A method for encoding a multi-channel signal, comprising: determining a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; determining target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal; generating parameter indication information, the parameter indication information being used to indicate the subbands corresponding to the target reverberation gain parameters; encoding the target reverberation gain parameters, the parameter indication information, and the downmix signal to generate a bitstream; A method for encoding a multi-channel signal, comprising:

2. determining target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal, determining the target reverberation gain parameter based on at least one of a coherence between an energy of the first channel signal and an energy of the downmix signal and a coherence between an energy of the second channel signal and the energy of the downmix signal; The method of claim 1 , comprising:

3. each of the first channel signal and the second channel signal comprises a plurality of frequency bins; determining the target reverberation gain parameter based on at least one of a coherence between an energy of the first channel signal and an energy of the downmix signal and a coherence between an energy of the second channel signal and the energy of the downmix signal, determining a first difference value between the energy of the first channel signal and the energy of the down-mix signal, wherein the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining, when the first difference value is greater than a first threshold, that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter, the first frequency band being a portion of all frequency bands of each of the first channel signal and the second channel signal; The method of claim 2, comprising:

4. each of the first channel signal and the second channel signal comprises a plurality of frequency bins; determining the target reverberation gain parameter based on at least one of a coherence between an energy of the first channel signal and an energy of the downmix signal and a coherence between an energy of the second channel signal and the energy of the downmix signal, determining a second difference value between the energy of the second channel signal and the energy of the down-mix signal, wherein the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining, when the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter, the first frequency band being a portion of all frequency bands of each of the first channel signal and the second channel signal; The method of claim 2, comprising:

5. each of the first channel signal and the second channel signal comprises a plurality of frequency bins; determining the target reverberation gain parameter based on at least one of a coherence between an energy of the first channel signal and an energy of the downmix signal and a coherence between an energy of the second channel signal and the energy of the downmix signal, determining a first difference value between the energy of the first channel signal and the energy of the down-mix signal, wherein the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining a second difference value between the energy of the second channel signal and the energy of the down-mix signal, wherein the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining, when the first difference value is greater than the first threshold and the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter, the first frequency band being a portion of all frequency bands of each of the first channel signal and the second channel signal; The method of claim 2, comprising:

6. 6. The method according to claim 3, wherein the frequency of the first frequency band is lower than the frequency of another frequency band different from the first frequency band in the first channel signal and the second channel signal.

7. 7. The method according to claim 3, wherein the plurality of frequency bins are within a second frequency band of each of the first channel signal and the second channel signal, and the frequency of the second frequency band is greater than the frequency of another frequency band different from the second frequency band in the first channel signal and the second channel signal.

8. determining target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal, determining the energies of N subbands of the downmix signal; determining M subbands from the N subbands, wherein an energy of any subband among the M subbands is greater than an energy of any subband among N-M subbands within the N subbands excluding the M subbands, where both M and N are integers greater than 0 and M is less than N; determining the target reverberation gain parameter based on a magnitude relationship between the energies of the M subbands and the N-M subbands; The method of claim 1 , comprising:

9. determining the target reverberation gain parameter based on a magnitude relationship between the energies of the M subbands and the N−M subbands, determining that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter when the sum of the energies of the M subbands is greater than L times the sum of the energies of the N-M subbands, wherein the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal, and L is a real number greater than 0; The method of claim 8, comprising:

10. determining target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal, determining the energies of N subbands of the downmix signal; determining M subbands from the N subbands, wherein an energy of any subband among the M subbands is greater than an energy of any subband among N−M subbands within the N subbands excluding the M subbands; determining a reverberation gain parameter corresponding to a subband of a first frequency band to be the target reverberation gain parameter when an index value of a first subband among the M subbands is smaller than a preset index value, wherein a frequency of any frequency bin in the first subband is greater than a frequency of any frequency bin in another subband among the M subbands excluding the first subband, and the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal; The method of claim 1 , comprising:

11. determining target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal, determining the energies of N subbands of the downmix signal; determining J target subbands from the N subbands based on the energies of the N subbands, wherein an energy of any subband among the J target subbands is greater than an energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; determining reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters; The method of claim 1 , comprising:

12. The method according to claim 2 , wherein the energy of the downmix signal is determined based on the energy of the first channel signal and the energy of the second channel signal.

13. 1. A method for decoding a multi-channel signal, comprising: receiving a bitstream; obtaining, based on the bitstream, downmix signals of a first channel signal and a second channel signal in a multi-channel signal and parameter indication information, wherein the parameter indication information is used to indicate encoded target reverberation gain parameters in reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; obtaining the target reverberation gain parameter from the bitstream according to the parameter indication; determining the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameter; A method for decoding a multi-channel signal, comprising:

14. 1. A method for encoding a multi-channel signal, comprising: determining a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; determining target reverberation gain parameters that need to be coded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal based on energies of N subbands of the downmix signal, where N is an integer greater than 0; encoding the downmix signal and the target reverberation gain parameters; A method for encoding a multi-channel signal, comprising:

15. determining, based on energies of N subbands of the downmix signal, target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal, determining J target subbands from the N subbands based on the energies of the N subbands, wherein an energy of any subband among the J target subbands is greater than an energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; determining reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters; The method of claim 14, comprising:

16. 1. A method for decoding a multi-channel signal, comprising: receiving a bitstream; determining a downmix signal of a first channel signal and a second channel signal in a multi-channel signal based on the bitstream; determining encoded target reverberation gain parameters among reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on energies of N subbands of the downmix signal, where N is an integer greater than 0; determining the target reverberation gain parameters based on the bitstream; determining the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameter; A method for decoding a multi-channel signal, comprising:

17. determining, based on energies of N subbands of the downmix signal, encoded target reverberation gain parameters among reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, determining J target subbands from the N subbands based on the energies of the N subbands, wherein an energy of any subband among the J target subbands is greater than an energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; determining reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters; The method of claim 16, comprising:

18. a processing unit configured to determine a downmix signal of a first channel signal and a second channel signal in the multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, the processing unit is further configured to determine target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal; a processing unit further configured to generate parameter indication information, the parameter indication information being used to indicate a subband corresponding to the target reverberation gain parameter; a coding unit configured to code the target reverberation gain parameters, the parameter indication information, and the downmix signal to generate a bitstream; An encoder comprising:

19. The processing unit specifically: determining the target reverberation gain parameter based on at least one of a coherence between an energy of the first channel signal and an energy of the downmix signal and a coherence between an energy of the second channel signal and the energy of the downmix signal; 20. The encoder of claim 18, configured to:

20. Each of the first channel signal and the second channel signal comprises a plurality of frequency bins, and the processing unit specifically: determining a first difference value between the energy of the first channel signal and the energy of the down-mix signal, wherein the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining, when the first difference value is greater than a first threshold, that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter, the first frequency band being a portion of all frequency bands of each of the first channel signal and the second channel signal; 20. The encoder of claim 19 configured to:

21. Each of the first channel signal and the second channel signal comprises a plurality of frequency bins, and the processing unit specifically: determining a second difference value between the energy of the second channel signal and the energy of the down-mix signal, wherein the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining, when the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter, wherein the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal; 20. The encoder of claim 19 configured to:

22. Each of the first channel signal and the second channel signal comprises a plurality of frequency bins, and the processing unit specifically: determining a first difference value between the energy of the first channel signal and the energy of the down-mix signal, wherein the first difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the first channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining a second difference value between the energy of the second channel signal and the energy of the down-mix signal, wherein the second difference value is used to indicate a sum of absolute values ​​of difference values ​​between the energy of the second channel signal and the energy of the down-mix signal in the plurality of frequency bins; determining, when the first difference value is greater than the first threshold and the second difference value is greater than a second threshold, that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter, wherein the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal; 20. The encoder of claim 19 configured to:

23. 23. The encoder of claim 20, wherein the frequency of the first frequency band is lower than the frequency of another frequency band different from the first frequency band in the first channel signal and the second channel signal.

24. 24. The encoder of claim 20, wherein the plurality of frequency bins are within a second frequency band of each of the first channel signal and the second channel signal, and the frequencies of the second frequency band are greater than the frequencies of another frequency band different from the second frequency band in the first channel signal and the second channel signal.

25. The processing unit specifically: determining the energies of N subbands of the downmix signal; determining M subbands from the N subbands, wherein an energy of any subband among the M subbands is greater than an energy of any subband among N-M subbands within the N subbands excluding the M subbands, where both M and N are integers greater than 0 and M is less than N; determining the target reverberation gain parameter based on a magnitude relationship between the energies of the M subbands and the N-M subbands; 20. The encoder of claim 18 configured to:

26. The processing unit specifically: determining that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter when the sum of the energies of the M subbands is greater than L times the sum of the energies of the N-M subbands, wherein the first frequency band is a portion of all frequency bands of each of the first channel signal and the second channel signal, and L is a real number greater than 0.

26. The encoder of claim 25 configured to:

27. The processing unit specifically: determining the energies of N subbands of the downmix signal; determining M subbands from the N subbands, wherein an energy of any subband among the M subbands is greater than an energy of any subband among N-M subbands within the N subbands excluding the M subbands; determining that a reverberation gain parameter corresponding to a subband of a first frequency band is the target reverberation gain parameter when an index value of a first subband among the M subbands is smaller than a preset index value, wherein a frequency of any frequency bin in the first subband is greater than a frequency of any frequency bin in another subband among the M subbands excluding the first subband, and the first frequency band is a part of all frequency bands of each of the first channel signal and the second channel signal; 20. The encoder of claim 18 configured to:

28. The processing unit specifically: determining the energies of N subbands of the downmix signal; determining J target subbands from the N subbands based on the energies of the N subbands, wherein an energy of any subband among the J target subbands is greater than an energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; determining reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters; 20. The encoder of claim 18 configured to:

29. 29. The encoder of claim 19, wherein the energy of the downmix signal is determined based on the energy of the first channel signal and the energy of the second channel signal.

30. an acquisition unit configured to receive a bitstream, the obtaining unit is further configured to obtain, based on the bitstream, a downmix signal of a first channel signal and a second channel signal in a multi-channel signal, and parameter indication information, wherein the parameter indication information is used to indicate encoded target reverberation gain parameters in reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal; an acquisition unit, the acquisition unit being further configured to acquire the target reverberation gain parameter from the bitstream according to the parameter indication information; a processing unit configured to determine the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameter; A decoder comprising:

31. 1. A processing unit configured to determine a downmix signal of a first channel signal and a second channel signal in a multi-channel signal and reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal, the processing unit comprising: a processing unit further configured to determine, based on energies of N subbands of the downmix signal, target reverberation gain parameters that need to be encoded within the reverberation gain parameters corresponding to the different subbands of the first channel signal and the second channel signal, where N is an integer greater than 0; a coding unit configured to code the downmix signal and the target reverberation gain parameter; An encoder comprising:

32. The processing unit specifically: determining J target subbands from the N subbands based on the energies of the N subbands, wherein an energy of any subband among the J target subbands is greater than an energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; determining reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters; 32. The encoder of claim 31 configured to:

33. a first acquisition unit configured to receive a bitstream; a first processing unit configured to determine a downmix signal of a first channel signal and a second channel signal in a multi-channel signal based on the bitstream; a second processing unit configured to determine encoded target reverberation gain parameters among reverberation gain parameters corresponding to different subbands of the first channel signal and the second channel signal based on energies of N subbands of the downmix signal, where N is an integer greater than 0; a third processing unit configured to determine the target reverberation gain parameters based on the bitstream; a fourth processing unit configured to determine the first channel signal and the second channel signal based on the downmix signal and the target reverberation gain parameter; and A decoder comprising:

34. The first processing unit specifically: determining J target subbands from the N subbands based on the energies of the N subbands of the downmix signal, where an energy of any subband among the J target subbands is greater than an energy of another subband different from the J target subbands, where both N and J are integers greater than 0 and J is less than N; determining reverberation gain parameters corresponding to the J target subbands as target reverberation gain parameters; 34. The decoder of claim 33, configured to:

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