Stereo encoding and decoding method, encoding and decoding device, system and storage medium

Abstract

The invention discloses a stereo coding and decoding method, a coding and decoding device, a system and a storage medium. The method executed by the encoder comprises the following steps: selecting a down-mixing processing strategy according to the correlation between a left channel signal and a right channel signal; determining a center channel signal and a side channel signal based on the selected down-mixing processing strategy; and determining first coded data according to the left channel signal, the right channel signal, the center channel signal, the side channel signal and the selected down-mixing processing strategy. In this way, efficient self-adaptive compression of all types of stereo signals is achieved, and the compression rate is improved.

Description

Technical Field

[0001] This disclosure relates to the field of communication technology, and in particular to a stereo encoding / decoding method, encoding / decoding device, system, and storage medium. Background Technology

[0002] As people's living standards improve, they have an increasingly higher pursuit of high-quality audio experiences and a greater demand for lossy encoding rates. However, because lossy encoding results in a decrease in sound quality, it still cannot meet people's needs for high-quality audio playback and storage. Compared to lossy audio, lossless audio retains all the information of the audio, thus becoming a solution. Lossless audio can achieve a certain degree of compression without losing any audio information and meet people's demand for lossless sound quality. Summary of the Invention

[0003] To improve audio compression rate, embodiments of this disclosure propose a stereo encoding / decoding method, encoding / decoding device, system, and storage medium.

[0004] According to a first aspect of the present disclosure, a stereo coding method is proposed, executed by an encoder, the method comprising: selecting a downmixing strategy based on the correlation between a left channel signal and a right channel signal; determining a center channel signal and a side channel signal based on the selected downmixing strategy; and determining first encoded data based on the left channel signal, the right channel signal, the center channel signal, the side channel signal, and the selected downmixing strategy.

[0005] According to a second aspect of the present disclosure, a stereo decoding method is proposed, executed by a decoder, the method comprising: decoding second encoded data in the first encoded data according to a downmixing strategy and encoding method indicated in the first encoded data to obtain a left channel signal and a right channel signal; wherein the downmixing strategy is selected by an encoder based on the correlation between the left channel signal and the right channel signal and used to determine a center channel signal and a side channel signal, and the second encoded data is encoded by the encoder according to the encoding method determined by the left channel signal, the right channel signal, the center channel signal, and the side channel signal.

[0006] According to a third aspect of the present disclosure, an encoding apparatus is provided for performing the stereo encoding method described in the first aspect.

[0007] According to a fourth aspect of the present disclosure, a decoding apparatus is provided for performing the stereo decoding method described in the second aspect.

[0008] According to a fifth aspect of the present disclosure, a stereo encoding and decoding system is proposed, including an encoder and a decoder, wherein the encoder is configured to implement the stereo encoding method described in the first aspect, and the decoder is configured to implement the stereo decoding method described in the second aspect.

[0009] According to a sixth aspect of the present disclosure, a storage medium is provided that stores instructions which, when executed on a communication device, cause the communication device to perform the method described in the first or second aspect.

[0010] According to a seventh aspect of the present disclosure, a program product is provided, comprising at least one of a program and instructions, wherein the program and instructions, when executed by a communication device, implement the method described in the first or second aspect.

[0011] By adopting the above technical solution, at least the following beneficial technical effects can be achieved:

[0012] This method, which selects the corresponding downmixing strategy based on the cross-correlation between the left and right channel signals, and efficiently determines the center and side channel signals based on the selected downmixing strategy to generate the first encoded data, achieves efficient adaptive compression of all types of stereo signals and improves the compression ratio. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings required for the description of the embodiments are introduced below. The following drawings are only some embodiments of this disclosure and do not impose specific limitations on the protection scope of this disclosure.

[0014] Figure 1A This is a schematic diagram of the architecture of an encoding / decoding system according to an embodiment of the present disclosure.

[0015] Figure 1B This is a flowchart illustrating a channel decorrelation process according to an embodiment of the present disclosure.

[0016] Figure 1C This is a flowchart illustrating a decoding process according to an embodiment of the present disclosure.

[0017] Figure 1D This is a schematic diagram of a signal according to an embodiment of the present disclosure.

[0018] Figure 1E This is a schematic diagram of a signal according to an embodiment of the present disclosure.

[0019] Figure 2A This is an interactive schematic diagram illustrating an encoding / decoding method according to an embodiment of the present disclosure.

[0020] Figure 2B This is an interactive schematic diagram illustrating an encoding / decoding method according to an embodiment of the present disclosure.

[0021] Figure 3A This is a flowchart illustrating an encoding method according to an embodiment of the present disclosure.

[0022] Figure 3B This is a flowchart illustrating an encoding method according to an embodiment of the present disclosure.

[0023] Figure 3C This is a flowchart illustrating a decoding method according to an embodiment of the present disclosure.

[0024] Figure 4A This is a flowchart illustrating an encoding end processing method according to an embodiment of the present disclosure.

[0025] Figure 4B This is a flowchart illustrating a decoding process according to an embodiment of the present disclosure.

[0026] Figure 5A This is a schematic diagram of the structure of an encoding device proposed in an embodiment of this disclosure.

[0027] Figure 5B This is a schematic diagram of the structure of a decoding device proposed in an embodiment of this disclosure.

[0028] Figure 6A This is a schematic diagram of the structure of a communication device according to an embodiment of the present disclosure.

[0029] Figure 6B This is a schematic diagram of the chip structure proposed according to an embodiment of the present disclosure. Detailed Implementation

[0030] This disclosure provides a stereo encoding / decoding method, encoding / decoding device, system, and storage medium.

[0031] In a first aspect, embodiments of this disclosure propose an encoding method executed by an encoder, the method comprising: selecting a downmixing strategy based on the correlation between a left channel signal and a right channel signal; determining a center channel signal and a side channel signal based on the selected downmixing strategy; and determining first encoded data based on the left channel signal, the right channel signal, the center channel signal, the side channel signal, and the selected downmixing strategy.

[0032] In the above embodiments, this method of selecting the corresponding downmixing processing strategy based on the cross-correlation between the left channel signal and the right channel signal, and efficiently determining the center channel signal and side channel signal based on the selected downmixing processing strategy to generate the first encoded data, achieves efficient adaptive compression of all types of stereo signals and improves the compression ratio.

[0033] In conjunction with some embodiments of the first aspect, in some embodiments, determining the first encoded data based on the left channel signal, the right channel signal, the center channel signal, the side channel signal, and the selected downmixing processing strategy includes: determining an encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signal; and determining the first encoded data based on the encoding method, second encoded data encoded based on the encoding method, and the selected downmixing processing strategy.

[0034] In the above embodiments, by comprehensively analyzing the left channel signal, right channel signal, center channel signal, and side channel signal, the encoding method with the fewest encoding bits can be determined. This encoding method can achieve the highest compression rate for various types of stereo signals while maintaining audio quality, which not only improves the encoding performance of the encoder but also enhances the robustness of the encoder.

[0035] In conjunction with some embodiments of the first aspect, in some embodiments, the step of selecting a downmixing processing strategy based on the correlation between the left channel signal and the right channel signal includes: determining the cross-correlation coefficient between the left channel signal and the right channel signal; and selecting a downmixing processing strategy based on the cross-correlation coefficient and a threshold.

[0036] In the above embodiments, the cross-correlation coefficient between the left and right channel signals is determined, and a downmixing strategy is selected based on the relationship between this coefficient and a threshold. This strategy selection method based on cross-correlation coefficients and thresholds makes downmixing more accurate and better adaptable to the characteristics of different types of input signals (i.e., left and right channel signals), thereby improving the efficiency, quality, and compression rate of audio coding.

[0037] In conjunction with some embodiments of the first aspect, in some embodiments, determining the cross-correlation coefficient between the left channel signal and the right channel signal includes: calculating the cross-correlation coefficient n using the following formula. LR :

[0038]

[0039] Where L represents the left channel signal, L i This represents the i-th sample point in the left channel signal. R represents the average value of n samples in the left channel signal, and R represents the right channel signal. i This represents the i-th sample point in the right channel signal. This represents the average value of n samples in the right channel signal.

[0040] In the above embodiments, the linear relationship between the two channel signals can be accurately quantified and evaluated based on the deviation between each sample point in the two channel signals and its respective average sample point value.

[0041] In conjunction with some embodiments of the first aspect, in some embodiments, the step of selecting a downmixing processing strategy based on the cross-correlation coefficient and a threshold includes: selecting a first downmixing processing strategy if the cross-correlation coefficient is less than the threshold; or selecting a second downmixing processing strategy if the cross-correlation coefficient is greater than or equal to the threshold.

[0042] In the above embodiments, by comparing the cross-correlation coefficient with a threshold, it is possible to distinguish whether the current frame signal (i.e., the left channel signal and the right channel signal) is a negatively correlated signal (biased out-of-phase signal) or a positively correlated signal (biased in-phase signal). If the cross-correlation coefficient is less than the threshold, it indicates that the current frame signal is a negatively correlated signal, and the first downmixing processing strategy is selected; if the cross-correlation coefficient is greater than or equal to the threshold, it indicates that the current frame signal is a positively correlated signal, and the second downmixing processing strategy is selected. This adaptive strategy selection based on signal correlation characteristics can achieve efficient adaptive compression of all types of stereo signals and improve the compression ratio, thereby optimizing the use of storage space and transmission bandwidth while maintaining sound quality.

[0043] In conjunction with some embodiments of the first aspect, in some embodiments, determining the center channel signal and the side channel signals based on the first downmixing processing strategy includes: calculating the center channel signal and the side channel signals using the following formula:

[0044] M = L + R

[0045]

[0046] Wherein, M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0047] In the above embodiments, because the negatively correlated stereo signal has the characteristic that the left and right channel signals exhibit opposite phase relationships at certain frequencies, this signal typically contains more stereo difference information, providing rich spatial sense and directionality. For the negatively correlated stereo signal, the center channel signal is calculated using M = L + R, and then... Calculating the side channel signals can improve the encoder's compression rate.

[0048] In conjunction with some embodiments of the first aspect, in some embodiments, determining the encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signals includes:

[0049] Determine the first number of bits required to encode the left channel signal and the right channel signal;

[0050] Determine the second number of bits required to encode the left channel signal and the center channel signal;

[0051] Determine the number of third bits required to encode the right channel signal and the center channel signal;

[0052] Determine the number of fourth bits required to encode the center channel signal and the side channel signals;

[0053] The encoding method is determined based on the minimum number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

[0054] In the above embodiments, by comparing the number of bits required to encode different channel combinations, an encoding method that minimizes the number of bits can be selected. This method comprehensively considers the left channel signal, right channel signal, center channel signal, and side channel signals. By determining the number of bits required to encode each pair of signals, the minimum number of bits is selected as the final encoding method. This strategy ensures that the amount of encoded data is minimized while maintaining sound quality, thereby achieving more efficient audio data compression.

[0055] In conjunction with some embodiments of the first aspect, in some embodiments, determining the center channel signal and the side channel signals based on the second downmixing processing strategy includes:

[0056] The center channel signal and the side channel signals are calculated according to the following formulas:

[0057]

[0058] S=LR

[0059] Wherein, M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0060] In the above embodiments, because the polarized stereo signal has the characteristic that the left and right channel signals exhibit the same phase relationship at certain frequencies, this signal typically contains more common information. Calculating the center channel signal and the side channel signals using S=LR can improve the encoder's compression rate.

[0061] In the above embodiments, different processing strategies are employed for different types of stereo signals to optimize coding efficiency and audio quality. For negatively correlated signals, coding efficiency and audio quality are improved by preserving more signal energy and stereo separation. For positively correlated signals, compression ratio and auditory experience are improved by balancing signal energy and preserving differential information. This differentiated processing method enables the encoder to adapt to different types of audio signals, achieving more efficient audio coding and a high compression ratio for each type of audio signal.

[0062] In conjunction with some embodiments of the first aspect, in some embodiments, determining the encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signals includes:

[0063] Determine the first number of bits required to encode the left channel signal and the right channel signal;

[0064] Determine the second number of bits required to encode the left channel signal and the side channel signal;

[0065] Determine the third number of bits required to encode the right channel signal and the side channel signal;

[0066] Determine the number of fourth bits required to encode the center channel signal and the side channel signals;

[0067] The encoding method is determined based on the minimum number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

[0068] In the above embodiments, by comparing the number of bits required to encode different channel combinations, an encoding method that minimizes the number of bits can be selected. This method comprehensively considers the left channel signal, right channel signal, center channel signal, and side channel signals. By determining the number of bits required to encode each pair of signals, the minimum number of bits is selected as the final encoding method. This strategy ensures that the amount of encoded data is minimized while maintaining sound quality, thereby achieving more efficient audio data compression.

[0069] In conjunction with some embodiments of the first aspect, in some embodiments, the method further includes: sending the first encoded data to the decoder.

[0070] Secondly, embodiments of this disclosure propose a stereo decoding method, executed by a decoder, the method comprising: decoding second encoded data in the first encoded data according to a downmixing processing strategy and encoding method indicated in the first encoded data to obtain a left channel signal and a right channel signal; wherein, the downmixing processing strategy is selected by the encoder based on the correlation between the left channel signal and the right channel signal and used to determine the center channel signal and the side channel signal, and the second encoded data is encoded by the encoder according to the encoding method determined by the left channel signal, the right channel signal, the center channel signal, and the side channel signal.

[0071] In conjunction with some embodiments of the second aspect, in some embodiments, the step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a first downmixing processing strategy or a second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the right channel signal, and the left channel signal and the right channel signal are obtained by decoding according to the second encoded data.

[0072] In conjunction with some embodiments of the second aspect, in some embodiments, decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a first downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the center channel signal; decoding the second encoded data to obtain the left channel signal and the center channel signal; and determining the right channel signal based on the left channel signal and the center channel signal using the following formula:

[0073] R = ML

[0074] Wherein, M represents the center channel signal, L represents the left channel signal, and R represents the right channel signal.

[0075] In conjunction with some embodiments of the second aspect, in some embodiments, decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a first downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the center channel signal; decoding the second encoded data to obtain the right channel signal and the center channel signal; and determining the left channel signal based on the right channel signal and the center channel signal using the following formula:

[0076] L = MR

[0077] Wherein, M represents the center channel signal, L represents the left channel signal, and R represents the right channel signal.

[0078] In conjunction with some embodiments of the second aspect, in some embodiments, decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes:

[0079] The downmixing processing strategy is a first downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal. The center channel signal and the side channel signal are obtained by decoding according to the second encoded data.

[0080] The left channel signal and the right channel signal are determined based on the center channel signal and the side channel signals using the following formula:

[0081] S′=2×S+(Mmod2)

[0082]

[0083] Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, R represents the right channel signal, and mod represents the modulo operator.

[0084] In conjunction with some embodiments of the second aspect, in some embodiments, decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the side channel signal; decoding the second encoded data to obtain the left channel signal and the side channel signal; and determining the right channel signal based on the left channel signal and the side channel signal using the following formula:

[0085] R = LS

[0086] Wherein, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0087] In conjunction with some embodiments of the second aspect, in some embodiments, decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes:

[0088] The downmixing strategy is the second downmixing strategy, and the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the side channel signal. The right channel signal and the side channel signal are obtained by decoding the second encoded data. The left channel signal is determined based on the right channel signal and the side channel signal using the following formula:

[0089] L = R + S

[0090] Wherein, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0091] In conjunction with some embodiments of the second aspect, in some embodiments, decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal; decoding the second encoded data to obtain the center channel signal and the side channel signal; and determining the left channel signal and the right channel signal based on the center channel signal and the side channel signal using the following formula:

[0092] M′=2×M+(Smod2)

[0093]

[0094] Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, R represents the right channel signal, and mod represents the modulo operator.

[0095] In conjunction with some embodiments of the second aspect, in some embodiments, before decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal, the method includes: receiving the first encoded data sent by the encoder.

[0096] Thirdly, embodiments of this disclosure provide an encoding device, which may include at least one of a transceiver module and a processing module; wherein the encoding device may be used to perform an optional implementation of the first aspect.

[0097] Fourthly, embodiments of this disclosure provide a decoding device, which may include at least one of a transceiver module and a processing module; wherein the decoding device may be used to perform an optional implementation of the second aspect.

[0098] Fifthly, embodiments of this disclosure provide an encoding apparatus that may include one or more processors; wherein the encoding apparatus may be used to perform an optional implementation of the first aspect.

[0099] In a sixth aspect, embodiments of this disclosure provide a decoding apparatus, which may include one or more processors; wherein the decoding apparatus may be used to perform an optional implementation of the second aspect.

[0100] In a seventh aspect, embodiments of this disclosure provide an encoding / decoding system that may include an encoder and a decoder; wherein the encoder is configured to perform the method described in the optional implementation of the first aspect, and the decoder is configured to perform the method described in the optional implementation of the second aspect.

[0101] Eighthly, embodiments of this disclosure provide a storage medium storing instructions that, when executed on a communication device, cause the communication device to perform the method as described in an optional implementation of the first or second aspect.

[0102] In a ninth aspect, embodiments of this disclosure provide a program product that, when executed by a communication device, causes the communication device to perform the method as described in an optional implementation of the first or second aspect.

[0103] In a tenth aspect, embodiments of this disclosure provide a computer program that, when run on a computer, causes the computer to perform the methods described in an optional implementation of the first or second aspect.

[0104] Eleventhly, embodiments of this disclosure provide a chip or chip system. The chip or chip system includes processing circuitry configured to perform the methods described in optional implementations of the first or second aspect.

[0105] It is understood that the encoders, decoders, encoding devices, decoding devices, storage media, program products, computer programs, chips, or chip systems described above can all be used to execute the methods proposed in the embodiments of this disclosure. Therefore, the beneficial effects they can achieve can be referred to the beneficial effects in the corresponding methods, and will not be repeated here.

[0106] This disclosure provides a stereo encoding / decoding method, encoding / decoding apparatus, system, and storage medium. In some embodiments, the terms stereo encoding / decoding method, lossless audio encoding / decoding method, audio compression and restoration method, and communication method can be used interchangeably.

[0107] This disclosure is not exhaustive, but merely illustrative of some embodiments, and is not intended to limit the scope of protection of this disclosure. Unless otherwise specified, each step in a particular embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a particular embodiment can also be implemented as an independent embodiment, and the order of the steps in a particular embodiment can be arbitrarily interchanged. Furthermore, the optional implementation methods in a particular embodiment can be arbitrarily combined; moreover, the embodiments can be arbitrarily combined, for example, some or all steps of different embodiments can be arbitrarily combined, and a particular embodiment can be arbitrarily combined with the optional implementation methods of other embodiments. In all embodiments of this disclosure, unless otherwise specified or logically conflicting, the terminology and / or descriptions between the embodiments are consistent and can be mutually referenced. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0108] The terminology used in the embodiments of this disclosure is for the purpose of describing particular embodiments only and is not intended to limit the scope of this disclosure.

[0109] In this embodiment of the disclosure, unless otherwise stated, elements expressed in the singular form, such as "a," "an," "the," "the," "the," "the," "the," "the," "this," etc., can mean "one and only one," or "one or more," "at least one," etc. For example, when using articles such as "a," "an," "the," etc. in translation, the noun following the article can be understood as either a singular expression or a plural expression.

[0110] In the embodiments disclosed herein, "multiple" refers to two or more.

[0111] In some embodiments, the terms “at least one of A or B, at least one of A and B”, “one or more”, “a plurality of”, “multiple”, etc., may be used interchangeably.

[0112] In some embodiments, the notation "at least one of A and B", "A and / or B", "A in one case, B in another", "in response to one case A, in response to another case B", etc., may include the following technical solutions depending on the situation: in some embodiments, A (execute A regardless of whether there is a branch B); in some embodiments, B (execute B regardless of whether there is a branch A); in some embodiments, execution is selected from A and B (A and B are selectively executed); in some embodiments, both A and B are executed. The same applies when there are more branches such as A, B, C, etc.

[0113] In some embodiments, the notation "A or B" may include the following technical solutions, depending on the situation: in some embodiments, A (execute A regardless of whether a branch B exists); in some embodiments, B (execute B regardless of whether a branch A exists); in some embodiments, execution is selected from A and B (A and B are selectively executed). The same applies when there are more branches such as A, B, and C.

[0114] The prefixes "first," "second," etc., used in the embodiments of this disclosure are merely for distinguishing different descriptive objects and do not impose restrictions on the position, order, priority, quantity, or content of the descriptive objects. The description of the descriptive objects is found in the claims or the context of the embodiments, and the use of prefixes should not constitute unnecessary restrictions. For example, if the descriptive object is a "field," the ordinal numbers preceding "field" in "first field" and "second field" do not restrict the position or order of the "fields." "First" and "second" do not restrict whether the "fields" they modify are in the same message, nor do they restrict the order of "first field" and "second field." Similarly, if the descriptive object is a "level," the ordinal numbers preceding "level" in "first level" and "second level" do not restrict the priority between "levels." Furthermore, the number of descriptive objects is not limited by ordinal numbers and can be one or more. For example, in "first device," the number of "devices" can be one or more. Furthermore, the objects modified by different prefixes can be the same or different. For example, if the object being described is "device", then "first device" and "second device" can be the same device or different devices, and their types can be the same or different. Similarly, if the object being described is "information", then "first information" and "second information" can be the same information or different information, and their content can be the same or different.

[0115] In some embodiments, “including A,” “containing A,” “for indicating A,” and “carrying A” can be interpreted as directly carrying A or indirectly indicating A.

[0116] In some embodiments, terms such as "time / frequency" and "time-frequency domain" refer to the time domain and / or frequency domain.

[0117] In some embodiments, terms such as “in response to…”, “in response to determining…”, “in the case of…”, “when…”, “when…”, “if…”, etc. can be used interchangeably. These descriptions all refer to the device making a corresponding action under certain objective circumstances. They do not necessarily limit the time, nor do they require the device to make a judgment action when implementing it, nor do they mean that there must be other limitations.

[0118] In some embodiments, the terms “greater than,” “greater than or equal to,” “not less than,” “more than,” “more than or equal to,” “not less than,” “higher than,” “higher than or equal to,” “not lower than,” and “above” can be used interchangeably, as can the terms “less than,” “less than or equal to,” “not greater than,” “less than,” “less than or equal to,” “not more than,” “lower than,” “lower than or equal to,” “not higher than,” and “below”.

[0119] In some embodiments, devices, etc., may be interpreted as physical or virtual, and their names are not limited to those described in the embodiments. Terms such as “device,” “equipment,” “circuit,” “network element,” “network function,” “network device,” “function,” “node,” “unit,” “section,” “system,” “network,” “chip,” “chip system,” “entity,” and “subject” are interchangeable.

[0120] In some embodiments, "network" can be interpreted as devices included in a network (e.g., access network devices, core network devices, etc.).

[0121] In some embodiments, the terms "access network device (AN device)," "radio access network device (RAN device)," "base station (BS)," "radio base station," "fixed station," "node," "access point," "transmission point (TP)," "reception point (RP)," "transmission / reception point (TRP)," "panel," "antenna panel," "antenna array," "cell," "macro cell," "small cell," "femto cell," "pico cell," "sector," "cell group," "serving cell," "carrier," "component carrier," and "bandwidth part (BWP)" can be used interchangeably.

[0122] In some embodiments, the terms "terminal", "terminal device", "user equipment (UE)", "user terminal", "mobile station (MS)", "mobile terminal (MT)", subscriber station, mobile unit, subscriber unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile subscriberstation, access terminal, mobile terminal, wireless terminal, remote terminal, handset, user agent, mobile client, and client can be used interchangeably.

[0123] In some embodiments, access network devices, core network devices, or network devices can be replaced by terminals. For example, embodiments of this disclosure can also be applied to structures where communication between access network devices, core network devices, or network devices and terminals is replaced by communication between multiple terminals (e.g., device-to-device (D2D), vehicle-to-everything (V2X), etc.). In this case, the structure can also be configured such that the terminal has all or part of the functions of the access network device. Furthermore, terms such as "uplink" and "downlink" can be replaced with terms corresponding to communication between terminals (e.g., "sidelink"). For example, uplink channel, downlink channel, etc., can be replaced with sidelink channel, and uplink link, downlink, etc., can be replaced with sidelink link.

[0124] In some embodiments, the terminal may be replaced by an access network device, a core network device, or a network device. In this case, the access network device, core network device, or network device may also be configured to have all or some of the functions of the terminal.

[0125] In some embodiments, the acquisition of data, information, etc., may comply with the laws and regulations of the country where the location is situated.

[0126] In some embodiments, data, information, etc., may be obtained with the user's consent.

[0127] Furthermore, each element, each row, or each column in the table of this disclosure can be implemented as an independent embodiment, and any combination of any element, any row, or any column can also be implemented as an independent embodiment.

[0128] Figure 1A This is a schematic diagram illustrating an encoding / decoding system according to an embodiment of this disclosure. Figure 1A As shown, the encoding / decoding system 100 may include an encoder 101 and a decoder 102. It should be noted that the encoding / decoding system 100 may also include other devices, and this disclosure does not limit the devices included in the encoding / decoding system 100.

[0129] In some embodiments, encoder 101 and / or decoder 102 may be a terminal or may be located within a terminal.

[0130] In some embodiments, the terminal may include at least one of, but is not limited to, a mobile phone, a wearable device, an Internet of Things device, a car with communication capabilities, a smart car, a tablet computer, a computer with wireless transceiver capabilities, a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a wireless terminal device in industrial control, a wireless terminal device in self-driving, a wireless terminal device in remote medical surgery, a wireless terminal device in a smart grid, a wireless terminal device in transportation safety, a wireless terminal device in a smart city, and a wireless terminal device in a smart home.

[0131] In some embodiments, encoder 101 and / or decoder 102 may be network devices or may be located within network devices.

[0132] In some embodiments, the network device may include at least one of an access network device and a core network device.

[0133] In some embodiments, the access network device is, for example, a node or device that connects a terminal to a wireless network. The access network device may include at least one of the following in a 5G communication system: evolved Node B (eNB), next-generation eNB (ng-eNB), next-generation Node B (gNB), node B (NB), home node B (HNB), home evolved node B (HeNB), radio backhaul device, radio network controller (RNC), base station controller (BSC), base transceiver station (BTS), base band unit (BBU), mobile switching center, base station in a 6G communication system, open RAN, cloud RAN, base station in other communication systems, and access node in a Wi-Fi system, but is not limited thereto.

[0134] In some embodiments, the access network device is a base station. Optionally, the base station may be, for example, a macro base station, a micro base station (also called a small station), a relay station, an access point, a 5 / 6G base station or a future base station, a satellite, a Transmitting and Receiving Point (TRP), a Transmitting Point (TP), a mobile switching center, or other equipment that performs base station functions in a communication system, etc., and this disclosure does not specifically limit this type of device. For ease of description, in all embodiments of this disclosure, the apparatus that provides wireless communication functions for terminal devices is collectively referred to as a network device or a base station.

[0135] In some embodiments, the core network equipment can be a single device, including a first network element, a second network element, etc., or it can be multiple devices or a group of devices, each including all or part of the first network element, the second network element, etc. Network elements can be virtual or physical. The core network includes, for example, at least one of the following: Evolved Packet Core (EPC), 5G / 6G Core Network (5G CN / 6G CN), and Next Generation Core (NGC).

[0136] In some embodiments, the technical solutions of this disclosure can be applied to the Open RAN architecture. In this case, the interfaces between or within access network devices involved in the embodiments of this disclosure can be transformed into internal interfaces of Open RAN. The processes and information interactions between these internal interfaces can be implemented by software or programs.

[0137] In some embodiments, the access network device may be composed of a central unit (CU) and a distributed unit (DU). The CU may also be called a control unit. The CU-DU structure can separate the protocol layer of the access network device. Some of the protocol layer functions are centrally controlled by the CU, while the remaining part or all of the protocol layer functions are distributed in the DU and centrally controlled by the CU. However, this is not the only possibility.

[0138] It is understood that the encoding and decoding system described in the embodiments of this disclosure is for the purpose of more clearly illustrating the technical solutions of the embodiments of this disclosure, and does not constitute a limitation on the technical solutions proposed in the embodiments of this disclosure. As those skilled in the art will know, with the evolution of system architecture and the emergence of new business scenarios, the technical solutions proposed in the embodiments of this disclosure are also applicable to similar technical problems.

[0139] The following embodiments of this disclosure can be applied to Figure 1A The encoding / decoding system 100 shown, or a part thereof, but not limited to it. Figure 1A The entities shown are examples; a codec system may include... Figure 1A All or part of the main body, or may include Figure 1A Other entities besides the main body, the number and form of each entity are arbitrary, each entity can be physical or virtual, the connection relationship between the entities is an example, the entities can be unconnected or connected, and the connection can be in any way, it can be a direct connection or an indirect connection, it can be a wired connection or a wireless connection.

[0140] The embodiments disclosed herein can be applied to Long Term Evolution (LTE), LTE-Advanced (LTE-A), LTE-Beyond (LTE-B), SUPER 3G, IMT-Advanced, 4th generation mobile communication system (4G), 5th generation mobile communication system (5G), 5G New Radio (NR), Future Radio Access (FRA), New-Radio Access Technology (RAT), New Radio (NR), New Radio Access (NX), Futuregeneration radio access (FX), Global System for Mobile communications (GSM), CDMA2000, Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), and IEEE 802.20, Ultra-Wideband (UWB), Bluetooth (a registered trademark), Public Land Mobile Network (PLMN) networks, Device-to-Device (D2D) systems, Machine-to-Machine (M2M) systems, Internet of Things (IoT) systems, Vehicle-to-Everything (V2X) systems, systems utilizing other communication methods, and next-generation systems built upon them, etc. Furthermore, multiple systems can be combined (e.g., a combination of LTE or LTE-A with 5G).

[0141] In some embodiments, the lossless coding framework is, for example, a hybrid mode of lossy and lossless modules; and a fully lossless mode with only lossless modules. The MPEG-4 SLS (MPEG-4 Lossless Audio Coding, where MPEG-4 refers to Moving Picture Experts Group 4, the series to which the standard belongs) standard adopts a hybrid mode architecture; Monkey's Audio, FLAC (Free Lossless Audio Codec), and WAVPack (Waveform Compressor) standards adopt a fully lossless mode. The AVS2-P3 of the Audio Video Coding Standard (AVS) provides a fully lossless mode with good flexibility, scalability, and efficiency.

[0142] In some embodiments, the channel decorrelation process is as follows: Figure 1B As shown, it includes: assuming the input signal is a stereo signal X(n), and the two channels of X(n) are L(n) and R(n) respectively, L(n) and R(n) are converted into S(n) and M(n) by the following formula.

[0143] S(n) = L(n) - R(n)

[0144]

[0145] Based on this, four candidate channel mapping schemes are constructed: LR, LS, RS, and MS, and the required number of encoded bits is calculated for each scheme. The encoder selects the scheme with the smallest total number of bits from the four mapping schemes and outputs the scheme's identifier Channel_assignment along with the encoded data.

[0146] In some embodiments, with Figure 1B The corresponding decoding process is as follows: Figure 1C As shown, this includes: first, parsing the input bitstream to obtain the Channel_assignment parameter value.

[0147] 1. When the Channel_assignment value is 0, the decoder selects the original LR channel data as input and directly recovers the left and right channel signals.

[0148] 2. When the Channel_assignment value is 1, the decoder selects the LS channel data as input. The left channel signal is obtained directly from the bitstream, and the right channel signal is calculated using the formula R=LS.

[0149] 3. When the Channel_assignment value is 2, the decoder selects the RS channel data as input. The right channel signal is obtained directly from the bitstream, and the left channel signal is calculated using the formula L = R + S.

[0150] 4. When the Channel_assignment value is 3, the decoder selects the MS channel data as input, where the left and right channel signals are recovered using the following formula:

[0151] M′=2×M+(Smod2)

[0152]

[0153] Here, mod represents the modulo operator.

[0154] In some embodiments, adopt Figure 1B and Figure 1C The method involves calculating the Mid (intermediate signal) and Sid (side signal) after submixing, and then constructing four mapping schemes (LR, LS, MS, RS) based on the L, R, M, and S channels, and evaluating the bit requirement for each channel. This processing method can improve the compression ratio when two channels are positively correlated or when two channels are slightly positive phase signals, meaning that the encoded bitstream size is smaller for the same input signal. Figure 1D The signal shown has a phase difference of nearly 0 degrees between the two channels at the same time. However, this does not improve the compression ratio for out-of-phase signals, such as... Figure 1E The signals shown have a phase difference of approximately 180 degrees between the two channels at the same time.

[0155] In view of this, embodiments of this disclosure propose a stereo encoding / decoding method, encoding / decoding device, system, and storage medium. By analyzing the cross-correlation of the input signal, and selecting the corresponding decorrelation processing method based on the analysis results, a high compression rate can be achieved for all types of signals, forming a highly efficient and adaptive two-channel decorrelation processing solution.

[0156] Figure 2A This is an interactive schematic diagram illustrating an encoding / decoding method according to an embodiment of this disclosure. This method can be executed by the aforementioned encoding / decoding system 100. For example... Figure 2A As shown, the method includes at least one of the following steps:

[0157] In step S2101, encoder 101 determines the cross-correlation between the left channel signal and the right channel signal.

[0158] In some embodiments, "cross-correlation" can be used interchangeably with terms such as "correlation," "phase relationship," and "similarity."

[0159] It should be noted that in stereo audio, an audio frame includes a left channel signal and a right channel signal, and each channel signal is composed of multiple samples. A sample refers to the amplitude value of an audio signal at a specific point in time. In digital audio, a sample is a discrete data point obtained by sampling a continuous audio signal.

[0160] In some embodiments, the cross-correlation between the left channel signal and the right channel signal can be analyzed based on each sample point in the left channel signal and each sample point in the right channel signal.

[0161] In some embodiments, a cross-correlation coefficient between the left channel signal and the right channel signal can be calculated based on a cross-correlation function, which represents the cross-correlation between the left channel signal and the right channel signal.

[0162] For example, the cross-correlation between the left and right channel signals can be calculated using the following formula:

[0163]

[0164] Where, n LR This represents the cross-correlation coefficient between the left and right channel signals, where L represents the left channel signal. i This represents the i-th sample point in the left channel signal. R represents the average of n samples in the left channel signal, and R represents the right channel signal. i This represents the i-th sample point in the right channel signal. This represents the average value of n samples in the right channel signal. n represents the total number of samples in the left / right channel signals, which is the length of an audio frame.

[0165] It should be noted that n LR The value range of is [-1, 1], where 1 indicates that the two signals are exactly the same (positive correlation) and -1 indicates that the two signals are completely opposite (negative correlation).

[0166] In step S2102, encoder 101 selects the first downmixing processing strategy based on the cross-correlation coefficient being less than the threshold.

[0167] In some embodiments, if the cross-correlation coefficient between the left channel signal and the right channel signal is less than a threshold, the left channel signal and the right channel signal can be considered as negatively correlated signals (inverted signals). In this case, a first downmixing processing strategy can be selected to calculate the center channel signal and the side channel signal.

[0168] In some embodiments, the threshold may be preset, adaptively set according to the scenario, specified by the protocol, or indicated by the network device; this disclosure does not limit the specific type of threshold. In some embodiments, the threshold may be represented as Thres1.

[0169] For example, when the cross-correlation coefficient between the left and right channel signals is in the range [-1, Thres1), the first downmixing processing strategy is selected.

[0170] In some embodiments, the selected downmixing strategy can be represented by a first parameter, such as flag. For example, flag=0 can be used to indicate that the selected downmixing strategy is the first downmixing strategy.

[0171] In some embodiments, "downmixing" can be used interchangeably with terms such as "decorrelation processing," "sum and difference processing," and "M / S (Mid / Side) processing."

[0172] In step S2103, encoder 101 determines the center channel signal and side channel signal according to the first downmixing processing strategy.

[0173] In some embodiments, determining the implementation of the center channel signal and side channel signal based on the first downmixing processing strategy includes: calculating the center channel signal and side channel signal using the following formula:

[0174] M = L + R

[0175]

[0176] Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0177] In step S2104, encoder 101 determines the first number of bits required to encode the left channel signal and the right channel signal.

[0178] In step S2105, encoder 101 determines the second number of bits required to encode the left channel signal and the center channel signal.

[0179] In step S2106, encoder 101 determines the number of third bits required to encode the right channel signal and the center channel signal.

[0180] In step S2107, encoder 101 determines the number of fourth bits required to encode the center channel signal and the side channel signals.

[0181] In some embodiments, when the center channel signal and side channel signals are determined according to the selected first downmixing processing strategy, four encoding schemes—LR, LM, RM, and MS—can be constructed based on the left channel signal, right channel signal, center channel signal, and side channel signals, and the number of bits required for each scheme is calculated. It should be noted that the center channel signal is frequently used in constructing these four mapping schemes (LR, LM, RM, MS) because negatively correlated stereo signals typically contain more stereo difference information, and relatively less common information. Encoding based on less information results in shorter encoded data, thus improving the compression ratio of the encoded data.

[0182] For example, the encoder determines the first number of bits required to encode the left channel signal L and the right channel signal R, the second number of bits required to encode the left channel signal L and the center channel signal M, the third number of bits required to encode the right channel signal R and the center channel signal M, and the fourth number of bits required to encode the center channel signal M and the side channel signal S.

[0183] In some embodiments, the terms "encoding method" can be used interchangeably with terms such as "mapping method," "quantization method," and "encoding strategy."

[0184] In some embodiments, the encoding method can be represented by a second parameter, such as Channel_assignment. For example, Channel_assignment = 0 can represent LR. For example, Channel_assignment = 1 can represent LM. For example, Channel_assignment = 2 can represent RM. For example, Channel_assignment = 3 can represent MS. It should be noted that the correspondence between the value of Channel_assignment and the encoding method here is only an example, and the correspondence between the value of Channel_assignment and the encoding method can also be other.

[0185] In step S2108, encoder 101 encodes the second encoded data according to the encoding method corresponding to the smallest number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

[0186] In some embodiments, the encoder selects the encoding method corresponding to the smallest number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits, and encodes the data according to the selected encoding method to obtain the second encoded data.

[0187] For example, suppose the smallest bit among the first bit number, the second bit number, the third bit number, and the fourth bit number is the first bit number, and the encoding method corresponding to the first bit number is LR. Encoding according to LR is to encode the left channel signal and the right channel signal to obtain the second encoded data.

[0188] For example, suppose the smallest bit among the first, second, third, and fourth bit counts is the second bit count, and the encoding method corresponding to the second bit count is LM. Encoding according to LM means encoding the left channel signal and the center channel signal to obtain the second encoded data.

[0189] For example, suppose the smallest bit among the first, second, third, and fourth bit numbers is the third bit number, and the encoding method corresponding to the third bit number is RM. Encoding according to RM is to encode the right channel signal and the center channel signal to obtain the second encoded data.

[0190] For example, suppose the smallest bit among the first, second, third, and fourth bit numbers is the fourth bit number, and the encoding method corresponding to the fourth bit number is MS. Encoding according to MS means encoding the center channel signal and the side channel signal to obtain the second encoded data.

[0191] In step S2109, encoder 101 determines the first encoded data based on the selected encoding method, the second encoded data, and the selected first downmixing processing strategy.

[0192] In some embodiments, the implementation of the encoder determining the first encoded data based on the selected encoding method, the second encoded data, and the selected first downmixing processing strategy includes: multiplexing the selected encoding method, the second encoded data, and the selected first downmixing processing strategy to obtain the first encoded data.

[0193] It should be explained that stream multiplexing refers to the process of packaging multiple data streams from different sources and of different types into a single data stream according to certain rules.

[0194] In some embodiments, the first encoded data includes a selected encoding method, second encoded data, and a selected first downmixing processing strategy. For example, the first encoded data includes a first parameter (e.g., flag), a second parameter (e.g., Channel_assignment), and second encoded data. The first parameter (e.g., flag) indicates the selected downmixing processing strategy, and the second parameter (e.g., Channel_assignment) indicates the selected encoding method.

[0195] In step S2110, encoder 101 sends the first encoded data to decoder.

[0196] In some embodiments, the decoder receives first encoded data.

[0197] In step S2111, the decoder 102 determines the selected downmixing processing strategy as the first downmixing processing strategy based on the first encoded data.

[0198] In some embodiments, the first encoded data may indicate the encoding method, the second encoded data, and the downmixing strategy.

[0199] In some embodiments, the first encoded data may include a first parameter (e.g., a flag), which indicates an under-mixing strategy.

[0200] For example, the decoder determines the downmixing strategy as the first downmixing strategy based on flag=0 in the first encoded data.

[0201] After step S2111, select one of steps S2112 to S2115 to determine the left channel signal and the right channel signal.

[0202] In step S2112, when the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the right channel signal, the decoder 102 decodes the left channel signal and the right channel signal according to the second encoded data.

[0203] In some embodiments, the first encoded data may include a second parameter (e.g., Channel_assignment), which indicates the encoding method.

[0204] For example, the decoder determines that the second encoded data is the encoding result of the left channel signal L and the right channel signal R based on Channel_assignment=0 in the first encoded data, and the decoder decodes the left channel signal and the right channel signal based on the second encoded data.

[0205] In step S2113, when the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the center channel signal, the decoder 102 decodes the left channel signal and the center channel signal according to the second encoded data, and determines the right channel signal according to the left channel signal and the center channel signal.

[0206] For example, the decoder determines that the second encoded data is the encoding result of the left channel signal L and the center channel signal M based on Channel_assignment=1 in the first encoded data. The decoder then decodes the left channel signal and the center channel signal based on the second encoded data. Furthermore, the decoder determines the right channel signal based on the left channel signal and the center channel signal.

[0207] One of the implementation methods for determining the right channel signal based on the left channel signal and the center channel signal includes: calculating the right channel signal based on R=ML.

[0208] In step S2114, when the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the center channel signal, the decoder 102 decodes the right channel signal and the center channel signal according to the second encoded data, and determines the left channel signal according to the right channel signal and the center channel signal.

[0209] For example, the decoder determines that the second encoded data is the encoding result of the right channel signal R and the center channel signal M based on Channel_assignment=2 in the first encoded data. The decoder then decodes the right channel signal and the center channel signal based on the second encoded data. Furthermore, the decoder determines the left channel signal based on the right channel signal and the center channel signal.

[0210] One of the implementation methods for determining the left channel signal based on the right channel signal and the center channel signal includes: calculating the left channel signal based on L=MR.

[0211] In step S2115, when the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal, the decoder 102 decodes the center channel signal and the side channel signal according to the second encoded data, and determines the left channel signal and the right channel signal according to the center channel signal and the side channel signal.

[0212] For example, the decoder determines that the second encoded data is the encoding result of the center channel signal M and the side channel signal S based on Channel_assignment=3 in the first encoded data. The decoder then decodes the center channel signal and the side channel signal based on the second encoded data. Furthermore, the decoder determines the left channel signal and the right channel signal based on the center channel signal and the side channel signal.

[0213] The implementation method for determining the left and right channel signals based on the center channel signal and side channel signals includes determining the left and right channel signals using the following formula:

[0214] S′=2×S+(Mmod2)

[0215]

[0216] Here, mod represents the modulo operator.

[0217] Using the above method, because negatively correlated stereo signals have the characteristic that the left and right channel signals exhibit opposite phase relationships at certain frequencies, such signals typically contain more stereo difference information, providing rich spatial sense and directionality. For negatively correlated stereo signals, the center channel signal is calculated using M = L + R, and then... The side channel signal is calculated, providing an idealized input for the subsequent adaptive bit allocation by the encoder, thereby improving the encoder's compression ratio and robustness. The decoder accurately decodes the second encoded data according to the specific downmixing strategy and encoding method, obtaining accurate left and right channel signals.

[0218] In some embodiments, the names of data, etc., are not limited to those described in the embodiments, and terms such as “data”, “information”, “signal”, “audio”, “voice”, and “sound wave” can be used interchangeably.

[0219] In some embodiments, “get”, “obtain”, “receive”, “transmit”, “bidirectional transmission”, “send and / or receive” can be used interchangeably.

[0220] In some embodiments, terms such as “send,” “transmit,” “report,” “distribute,” “transfer,” “bidirectional transmission,” “send and / or receive” can be used interchangeably.

[0221] The methods involved in the embodiments of this disclosure may include at least one of the steps S2101 to S2115 described above. For example, step S2102 may be implemented as an independent embodiment, steps S2104, S2105, S2106, and S2107 may be implemented as independent embodiments, step S2111 may be implemented as an independent embodiment, step S2112 may be implemented as an independent embodiment, step S2113 may be implemented as an independent embodiment, step S2114 may be implemented as an independent embodiment, and step S2115 may be implemented as an independent embodiment, but are not limited thereto.

[0222] In some embodiments, the order of any two steps S2101 to S2115 can be interchanged or they can be performed simultaneously. For example, the order of steps S2104 and S2105 can be interchanged or they can be performed simultaneously. For example, the order of steps S2106 and S2107 can be interchanged or they can be performed simultaneously.

[0223] In some embodiments, steps S2101 to S2115 are optional, and one or more of these steps may be omitted or substituted in different embodiments.

[0224] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0225] Figure 2B This is an interactive schematic diagram illustrating an encoding / decoding method according to an embodiment of this disclosure. This method can be executed by the aforementioned encoding / decoding system 100. For example... Figure 2B As shown, the method includes at least one of the following steps:

[0226] In step S2201, encoder 101 determines the correlation between the left channel signal and the right channel signal.

[0227] In some embodiments, "correlation" can be used interchangeably with terms such as "cross-correlation," "phase relationship," and "similarity."

[0228] It should be noted that in stereo audio, an audio frame includes a left channel signal and a right channel signal, and each channel signal is composed of multiple samples. A sample refers to the amplitude value of an audio signal at a specific point in time. In digital audio, a sample is a discrete data point obtained by sampling a continuous audio signal.

[0229] In some embodiments, the correlation between the left and right channel signals can be analyzed based on each sample in the left channel signal and each sample in the right channel signal.

[0230] In some embodiments, a cross-correlation coefficient between the left channel signal and the right channel signal can be calculated based on a cross-correlation function, which represents the correlation between the left channel signal and the right channel signal.

[0231] For example, the cross-correlation between the left and right channel signals can be calculated using the following formula:

[0232]

[0233] Where, n LR This represents the cross-correlation coefficient between the left and right channel signals, where L represents the left channel signal. i This represents the i-th sample point in the left channel signal. R represents the average of n samples in the left channel signal, and R represents the right channel signal. i This represents the i-th sample point in the right channel signal. This represents the average value of n samples in the right channel signal. n represents the total number of samples in the left / right channel signals, which is the length of an audio frame.

[0234] It should be noted that n LRThe value range of is [-1, 1], where 1 indicates that the two signals are exactly the same (positive correlation) and -1 indicates that the two signals are completely opposite (negative correlation).

[0235] In step S2202, encoder 101 selects a second downmixing processing strategy based on the cross-correlation coefficient being greater than or equal to a threshold.

[0236] In some embodiments, if the cross-correlation coefficient between the left channel signal and the right channel signal is greater than or equal to a threshold, the left channel signal and the right channel signal can be considered as positively correlated signals (positively phased signals). In this case, a second downmixing processing strategy can be selected to calculate the center channel signal and the side channel signal.

[0237] In some embodiments, the threshold may be preset, adaptively set according to the scenario, specified by the protocol, or indicated by the network device; this disclosure does not limit the specific type of threshold. In some embodiments, the threshold may be represented as Thres1.

[0238] For example, when the cross-correlation coefficient between the left and right channel signals is in the range [Thres1, 1], the second downmixing strategy is selected.

[0239] In some embodiments, the selected downmixing strategy can be represented by a first parameter, such as flag. For example, flag=1 can be used to indicate that the selected downmixing strategy is the second downmixing strategy.

[0240] In some embodiments, "downmixing" can be used interchangeably with terms such as "decorrelation processing," "sum and difference processing," and "M / S (Mid / Side) processing."

[0241] In step S2203, encoder 101 determines the center channel signal and side channel signal according to the second downmixing processing strategy.

[0242] In some embodiments, determining the center channel signal and side channel signal according to the second downmixing processing strategy includes calculating the center channel signal and side channel signal according to the following formula:

[0243]

[0244] S=LR

[0245] Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0246] In step S2204, encoder 101 determines the first number of bits required to encode the left channel signal and the right channel signal.

[0247] In step S2205, encoder 101 determines the second number of bits required to encode the left channel signal and the side channel signal.

[0248] In step S2206, encoder 101 determines the third number of bits required to encode the right channel signal and the side channel signal.

[0249] In step S2207, encoder 101 determines the number of fourth bits required to encode the center channel signal and the side channel signals.

[0250] In some embodiments, when the center channel signal and side channel signals are determined according to the selected second downmixing processing strategy, four encoding schemes, LR, LS, RS, and MS, can be constructed based on the left channel signal, right channel signal, center channel signal, and side channel signals, and the number of bits required for each scheme is calculated. It should be noted that the construction of these four mapping schemes (LR, LS, RS, MS) primarily utilizes side channel signals because positively correlated stereo signals typically contain more common information, and relatively less stereo difference information. Encoding based on less information results in shorter encoded data length, thereby improving the compression ratio of the encoded data.

[0251] For example, the encoder determines the first number of bits required to encode the left channel signal L and the right channel signal R, the second number of bits required to encode the left channel signal L and the side channel signal S, the third number of bits required to encode the right channel signal R and the side channel signal S, and the fourth number of bits required to encode the center channel signal M and the side channel signal S.

[0252] In some embodiments, the terms "encoding method" can be used interchangeably with terms such as "mapping method," "quantization method," and "encoding strategy."

[0253] In some embodiments, the encoding method can be represented by a second parameter, such as Channel_assignment. For example, Channel_assignment = 0 can represent LR. For example, Channel_assignment = 1 can represent LS. For example, Channel_assignment = 2 can represent RS. For example, Channel_assignment = 3 can represent MS. It should be noted that the correspondence between the value of Channel_assignment and the encoding method here is only an example, and the correspondence between the value of Channel_assignment and the encoding method can also be other.

[0254] In step S2208, encoder 101 encodes the second encoded data according to the encoding method corresponding to the smallest number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

[0255] In some embodiments, the encoder selects the encoding method corresponding to the smallest number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits, and encodes the data according to the selected encoding method to obtain the second encoded data.

[0256] For example, suppose the smallest bit among the first bit number, the second bit number, the third bit number, and the fourth bit number is the first bit number, and the encoding method corresponding to the first bit number is LR. Encoding according to LR is to encode the left channel signal and the right channel signal to obtain the second encoded data.

[0257] For example, suppose the smallest number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits is the second number of bits. The encoding method corresponding to the second number of bits is LS. Encoding according to LS means encoding the left channel signal and the side channel signal to obtain the second encoded data.

[0258] For example, suppose the smallest number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits is the third number of bits, and the encoding method corresponding to the third number of bits is RS. Encoding according to RS means encoding the right channel signal and the side channel signal to obtain the second encoded data.

[0259] For example, suppose the smallest bit among the first, second, third, and fourth bit numbers is the fourth bit number, and the encoding method corresponding to the fourth bit number is MS. Encoding according to MS means encoding the center channel signal and the side channel signal to obtain the second encoded data.

[0260] In step S2209, encoder 101 determines the first encoded data based on the selected encoding method, the second encoded data, and the selected second downmixing processing strategy.

[0261] In some embodiments, the implementation of the encoder determining the first encoded data based on the selected encoding method, the second encoded data, and the selected second downmixing processing strategy includes: multiplexing the selected encoding method, the second encoded data, and the selected second downmixing processing strategy to obtain the first encoded data.

[0262] It should be explained that stream multiplexing refers to the process of packaging multiple data streams from different sources and of different types into a single data stream according to certain rules.

[0263] In some embodiments, the first encoded data includes a selected encoding method, second encoded data, and a selected second downmixing strategy. For example, the first encoded data includes a first parameter (e.g., flag), a second parameter (e.g., Channel_assignment), and second encoded data. The first parameter (e.g., flag) indicates the selected downmixing strategy, and the second parameter (e.g., Channel_assignment) indicates the selected encoding method.

[0264] In step S2210, encoder 101 sends the first encoded data to decoder.

[0265] In some embodiments, the decoder receives first encoded data.

[0266] In step S2211, the decoder 102 determines the selected downmixing processing strategy as the second downmixing processing strategy based on the first encoded data.

[0267] In some embodiments, the first encoded data may indicate the encoding method, the second encoded data, and the downmixing strategy.

[0268] In some embodiments, the first encoded data may include a first parameter (e.g., a flag), which indicates an under-mixing strategy.

[0269] For example, the decoder determines the downmixing strategy as the second downmixing strategy based on flag=1 in the first encoded data.

[0270] After step S2211, select one of steps S2212 to S2215 to determine the left channel signal and the right channel signal.

[0271] In step S2212, when the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the right channel signal, the decoder 102 decodes the left channel signal and the right channel signal according to the second encoded data.

[0272] In some embodiments, the first encoded data may include a second parameter (e.g., Channel_assignment), which indicates the encoding method.

[0273] For example, the decoder determines that the second encoded data is the encoding result of the left channel signal L and the right channel signal R based on Channel_assignment=0 in the first encoded data, and the decoder decodes the left channel signal and the right channel signal based on the second encoded data.

[0274] In step S2213, when the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the side channel signal, the decoder 102 decodes the left channel signal and the side channel signal according to the second encoded data, and determines the right channel signal according to the left channel signal and the side channel signal.

[0275] For example, the decoder determines that the second encoded data is the encoding result of the left channel signal L and the side channel signal S based on Channel_assignment=1 in the first encoded data. The decoder then decodes the left channel signal and the side channel signal based on the second encoded data. Furthermore, the decoder determines the right channel signal based on the left channel signal and the side channel signal.

[0276] One of the implementation methods for determining the right channel signal based on the left channel signal and the side channel signal includes: calculating the right channel signal based on R=LS.

[0277] In step S2214, when the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the side channel signal, the decoder 102 decodes the right channel signal and the side channel signal according to the second encoded data, and determines the left channel signal according to the right channel signal and the side channel signal.

[0278] For example, the decoder determines that the second encoded data is the encoding result of the right channel signal R and the side channel signal S based on Channel_assignment=2 in the first encoded data. The decoder then decodes the right channel signal and the side channel signal based on the second encoded data. Furthermore, the decoder determines the left channel signal based on the right channel signal and the side channel signal.

[0279] One of the implementation methods for determining the left channel signal based on the right channel signal and the side channel signal includes: calculating the left channel signal based on L = R + S.

[0280] In step S2215, when the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal, the decoder 102 decodes the center channel signal and the side channel signal according to the second encoded data, and determines the left channel signal and the right channel signal according to the center channel signal and the side channel signal.

[0281] For example, the decoder determines that the second encoded data is the encoding result of the center channel signal M and the side channel signal S based on Channel_assignment=3 in the first encoded data. The decoder then decodes the center channel signal and the side channel signal based on the second encoded data. Furthermore, the decoder determines the left channel signal and the right channel signal based on the center channel signal and the side channel signal.

[0282] The implementation method for determining the left and right channel signals based on the center channel signal and side channel signals includes determining the left and right channel signals using the following formula:

[0283] M′=2×M+(Smod2)

[0284]

[0285] Here, mod represents the modulo operator.

[0286] Using the above method, because the positively correlated stereo signal has the characteristic that the left and right channel signals exhibit the same phase relationship at certain frequencies, this signal usually contains more common information. Calculating the center channel signal and then using S=LR to calculate the side channel signals can improve the encoder's compression ratio. The decoder accurately decodes the second encoded data according to the specific downmixing strategy and encoding method to obtain accurate left and right channel signals.

[0287] The methods involved in the embodiments of this disclosure may include at least one of the steps S2201 to S2215 described above. For example, step S2202 may be implemented as an independent embodiment, steps S2204, S2205, S2206, and S2207 may be implemented as independent embodiments, step S2211 may be implemented as an independent embodiment, step S2212 may be implemented as an independent embodiment, step S2213 may be implemented as an independent embodiment, step S2214 may be implemented as an independent embodiment, and step S2215 may be implemented as an independent embodiment, but are not limited thereto.

[0288] In some embodiments, the order of any two steps S2201 to S2215 can be interchanged or they can be performed simultaneously. For example, the order of steps S2204 and S2205 can be interchanged or they can be performed simultaneously. For example, the order of steps S2206 and S2207 can be interchanged or they can be performed simultaneously.

[0289] In some embodiments, steps S2201 to S2215 are optional, and one or more of these steps may be omitted or substituted in different embodiments.

[0290] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0291] Figure 3A This is a flowchart illustrating an encoding method according to an embodiment of the present disclosure. The method can be executed by the encoder 101 described above. Figure 3A As shown, the method includes at least one of the following steps:

[0292] Step S3101: Determine the cross-correlation coefficient between the left channel signal and the right channel signal.

[0293] For optional implementations of step S3101, please refer to [link / reference]. Figure 2A Step S2101 Figure 2B Optional implementation methods of step S2201, and Figure 2A , Figure 2B Other related parts in the embodiments involved will not be described in detail here.

[0294] Step S3102: Determine whether the cross-correlation coefficient is less than the threshold.

[0295] Step S3103: If the cross-correlation coefficient is less than the threshold, then the center channel signal and the side channel signal are determined based on the first downmixing processing strategy.

[0296] For optional implementations of step S3103, please refer to [link / reference]. Figure 2A Optional implementation methods of steps S2102 and S2103, and Figure 2A Other related parts in the embodiments involved will not be described in detail here.

[0297] Step S3104: Calculate the number of bits required for encoding LR, LM, RM, and MS respectively, and select the encoding method corresponding to the minimum number of bits.

[0298] For optional implementations of step S3104, please refer to [link / reference]. Figure 2A Optional implementation methods of steps S2104 to S2108, and Figure 2A Other related parts in the embodiments involved will not be described in detail here.

[0299] Step S3105: Determine the first encoded data based on the selected encoding method, the second encoded data obtained by encoding based on the selected encoding method, and the first downmixing processing strategy.

[0300] For optional implementations of step S3105, please refer to [link / reference]. Figure 2A Optional implementation methods of step S2109, and Figure 2A Other related parts in the embodiments involved will not be described in detail here.

[0301] Step S3106: If the cross-correlation coefficient is greater than or equal to the threshold, then the center channel signal and side channel signal are determined based on the second downmixing processing strategy.

[0302] Optional implementations of step S3106 can be found in [reference]. Figure 2BOptional implementation methods for steps S2202 and S2203, and Figure 2B Other related parts in the embodiments involved will not be described in detail here.

[0303] Step S3107: Calculate the number of bits required to encode LR, LS, RS, and MS respectively, and select the encoding method corresponding to the minimum number of bits.

[0304] Optional implementations of step S3107 can be found in [reference]. Figure 2B Optional implementation methods for steps S2204 to S2208, and Figure 2B Other related parts in the embodiments involved will not be described in detail here.

[0305] Step S3108: Determine the first encoded data based on the selected encoding method, the second encoded data obtained by encoding based on the selected encoding method, and the second downmixing processing strategy.

[0306] For optional implementations of step S3108, please refer to [link / reference]. Figure 2B Optional implementation methods of step S2209, and Figure 2B Other related parts in the embodiments involved will not be described in detail here.

[0307] The methods involved in the embodiments of this disclosure may include at least one of the steps S3101 to S3108 described above. For example, step S3103 may be implemented as an independent embodiment, step S3106 may be implemented as an independent embodiment, steps S3103, S3104, and S3105 may be implemented as independent embodiments, and steps S3106, S3107, and S3108 may be implemented as independent embodiments, but are not limited thereto.

[0308] In some embodiments, steps S3101 to S3108 are optional, and one or more of these steps may be omitted or substituted in different embodiments.

[0309] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0310] Figure 3B This is a flowchart illustrating an encoding method according to an embodiment of the present disclosure. The method can be executed by the encoder 101 described above. Figure 3B As shown, the method includes at least one of the following steps:

[0311] Step S3201: Select a downmixing processing strategy based on the correlation between the left channel signal and the right channel signal.

[0312] Optionally, the step of selecting a downmixing processing strategy based on the correlation between the left channel signal and the right channel signal includes: determining the cross-correlation coefficient between the left channel signal and the right channel signal; and selecting a downmixing processing strategy based on the cross-correlation coefficient and a threshold.

[0313] Optionally, determining the cross-correlation coefficient between the left channel signal and the right channel signal includes: calculating the cross-correlation coefficient n using the following formula. LR :

[0314]

[0315] Where L represents the left channel signal, L i This represents the i-th sample point in the left channel signal. R represents the average value of n samples in the left channel signal, and R represents the right channel signal. i This represents the i-th sample point in the right channel signal. This represents the average value of n samples in the right channel signal.

[0316] Optionally, the step of selecting a downmixing processing strategy based on the cross-correlation coefficient and the threshold includes: selecting a first downmixing processing strategy if the cross-correlation coefficient is less than the threshold; or selecting a second downmixing processing strategy if the cross-correlation coefficient is greater than or equal to the threshold.

[0317] Step S3202: Determine the center channel signal and side channel signals based on the selected downmixing processing strategy.

[0318] Optionally, determining the center channel signal and the side channel signal based on the first downmixing processing strategy includes: calculating the center channel signal and the side channel signal using the following formula:

[0319] M = L + R

[0320]

[0321] Wherein, M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0322] Optionally, determining the center channel signal and the side channel signals based on the second downmixing processing strategy includes: calculating the center channel signal and the side channel signals according to the following formula:

[0323]

[0324] S=LR

[0325] Wherein, M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0326] Step S3203: Determine the first encoded data based on the left channel signal, right channel signal, center channel signal, side channel signal, and the selected downmixing processing strategy.

[0327] Optionally, determining the first encoded data based on the left channel signal, the right channel signal, the center channel signal, the side channel signal, and the selected downmixing processing strategy includes: determining an encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signal; and determining the first encoded data based on the encoding method, the second encoded data encoded based on the encoding method, and the selected downmixing processing strategy.

[0328] Optionally, determining the encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signal includes: determining a first number of bits required to encode the left channel signal and the right channel signal; determining a second number of bits required to encode the left channel signal and the center channel signal; determining a third number of bits required to encode the right channel signal and the center channel signal; determining a fourth number of bits required to encode the center channel signal and the side channel signal; and determining the encoding method based on the minimum number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

[0329] Optionally, determining the encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signal includes: determining a first number of bits required to encode the left channel signal and the right channel signal; determining a second number of bits required to encode the left channel signal and the side channel signal; determining a third number of bits required to encode the right channel signal and the side channel signal; determining a fourth number of bits required to encode the center channel signal and the side channel signal; and determining the encoding method based on the minimum number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

[0330] Optionally, the method further includes sending the first encoded data to the decoder.

[0331] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0332] Figure 3CThis is a flowchart illustrating a decoding method according to an embodiment of the present disclosure. The method can be executed by the decoder 102 described above. Figure 3C As shown, the method includes at least one of the following steps:

[0333] Step S3301: Decode the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal.

[0334] The downmixing processing strategy is that the encoder selects and uses the correlation between the left channel signal and the right channel signal to determine the center channel signal and the side channel signal. The second encoded data is encoded by the encoder according to the encoding method determined by the left channel signal, the right channel signal, the center channel signal, and the side channel signal.

[0335] Optionally, the step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a first downmixing processing strategy or a second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the right channel signal, and the left channel signal and the right channel signal are obtained by decoding according to the second encoded data.

[0336] Optionally, the step of decoding the second encoded data in the first encoded data according to the downmixing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing strategy is a first downmixing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the center channel signal; the left channel signal and the center channel signal are decoded according to the second encoded data; and the right channel signal is determined according to the left channel signal and the center channel signal using the following formula:

[0337] R = ML

[0338] Wherein, M represents the center channel signal, L represents the left channel signal, and R represents the right channel signal.

[0339] Optionally, the step of decoding the second encoded data in the first encoded data according to the downmixing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing strategy is a first downmixing strategy, and the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the center channel signal; the right channel signal and the center channel signal are decoded according to the second encoded data; and the left channel signal is determined according to the right channel signal and the center channel signal using the following formula:

[0340] L = MR

[0341] Wherein, M represents the center channel signal, L represents the left channel signal, and R represents the right channel signal.

[0342] Optionally, the step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a first downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal; the center channel signal and the side channel signal are decoded according to the second encoded data; and the left channel signal and the right channel signal are determined according to the center channel signal and the side channel signal using the following formula:

[0343] S′=2×S+(Mmod2)

[0344]

[0345] Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, R represents the right channel signal, and mod represents the modulo operator.

[0346] Optionally, the step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing processing strategy is a second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the side channel signal; the left channel signal and the side channel signal are decoded according to the second encoded data; and the right channel signal is determined according to the left channel signal and the side channel signal using the following formula:

[0347] R = LS

[0348] Wherein, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0349] Optionally, the step of decoding the second encoded data in the first encoded data according to the downmixing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing strategy is a second downmixing strategy, and the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the side channel signal; the right channel signal and the side channel signal are decoded according to the second encoded data; and the left channel signal is determined according to the right channel signal and the side channel signal using the following formula:

[0350] L = R + S

[0351] Wherein, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

[0352] Optionally, the step of decoding the second encoded data in the first encoded data according to the downmixing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: the downmixing strategy is a second downmixing strategy, and the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal; the center channel signal and the side channel signal are decoded according to the second encoded data; and the left channel signal and the right channel signal are determined according to the center channel signal and the side channel signal using the following formula:

[0353] M′=2×M+(Smod2)

[0354]

[0355] Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, R represents the right channel signal, and mod represents the modulo operator.

[0356] Optionally, before decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal, the method includes: receiving the first encoded data sent by the encoder.

[0357] In some embodiments, the steps and their optional implementations in other embodiments described before or after this embodiment, as well as other related parts in the specification, can be referred to, and will not be repeated here.

[0358] It should be noted that this disclosure improves the performance of the channel decorrelation and channel decorrelation reconstruction modules in the encoding and decoding framework of related technologies. That is, the compression ratio of the encoding after adopting the embodiments of this disclosure is higher than the compression ratio of the encoding in related technologies.

[0359] In some embodiments, such as Figure 4A As shown, the encoding end processing flow includes:

[0360] The decorrelation process is as follows: The input signal is a stereo signal X(n), and the two channels of X(n) are L(n) and R(n). Cross-correlation analysis is performed on L(n) and R(n). The cross-correlation calculation formula for L(n) and R(n) is as follows:

[0361]

[0362] Where, n LR L represents the cross-correlation coefficient, and L represents the left channel signal. i This represents the i-th sample point in the left channel signal. R represents the average of n samples in the left channel signal, and R represents the right channel signal. i This represents the i-th sample point in the right channel signal. This represents the average value of n samples in the right channel signal.

[0363] The threshold Thres1 can be preset or adaptively set, and method A or method B can be adaptively selected based on the cross-correlation of the vocal tracts.

[0364] 1. Method A: If the correlation values ​​of the two channels in the current frame are in the range [-1, Thres1), it indicates that the current frame signal is a negatively correlated signal (biased inverse signal). In this case, the following formula is used for sum-difference downmixing. The resulting Mid and Sid channels are sent to the next processing unit, the flag value is set to 0, and the data is written into the bitstream and sent to the decoder.

[0365]

[0366] M = L + R

[0367] The next processing unit is used to perform the following processing: calculate the number of bits occupied by the encoding LR, LM, RM, and MS respectively, select the encoding method with the smallest number of bits for encoding, and write the identifier Channel_assignment (channel_allocation) representing the encoding method together with the encoded data into the bit stream and send it to the decoding end.

[0368] 2. Method B: When the correlation values ​​of the two channels are in [Thres1, 1], it indicates that the current frame signal is a positively correlated signal (positively phased signal). At this time, the following formula is used for sum-difference downmixing. The resulting Mid and Sid channels are sent to the next processing unit, the flag value is set to 1, and they are written into the bitstream and sent to the decoding end:

[0369] S=LR

[0370]

[0371] The next processing unit is used to perform the following processing: calculate the number of bits occupied by encoding LR, LS, RS, and MS respectively, select the encoding method with the smallest number of bits for encoding, and write the identifier Channel_assignment (channel_allocation) representing the encoding method together with the encoded data into the bit stream and send it to the decoding end.

[0372] In some embodiments, such as Figure 4B As shown, the decoding process includes:

[0373] 1. When the flag value is 0, different processing is performed based on the value of the Channel_assignment flag, specifically:

[0374] a. When the Channel_assignment value is 0, the decoder selects the original LR channel data as the output and directly recovers the left and right channel signals.

[0375] b. When the Channel_assignment value is 1, the decoder selects the LM channel data as input. The left channel signal is obtained directly from the bitstream, and the right channel signal is calculated using the formula R=ML.

[0376] c. When the Channel_assignment value is 2, the decoder selects the RM channel data as input. The right channel signal is obtained directly from the bitstream, and the left channel signal is calculated using the formula L=MR.

[0377] d. When Channel_assignment is 3, the decoder selects MS channel data as input, where the left and right channel signals are recovered using the following formula:

[0378] S′=2×S+(Mmod2)

[0379]

[0380] 2. When the flag value is 1, different processing is performed based on the value of the Channel_assignment flag, specifically:

[0381] a. When the Channel_assignment value is 0, the decoder selects the original LR channel data as the output and directly recovers the left and right channel signals.

[0382] b. When the Channel_assignment value is 1, the decoder selects the LS channel data as input. The left channel signal is obtained directly from the bitstream, and the right channel signal is calculated using the formula R=LS.

[0383] c. When the Channel_assignment value is 2, the decoder selects the RS channel data as input. The right channel signal is obtained directly from the bitstream, and the left channel signal is calculated using the formula L = R + S.

[0384] d. When Channel_assignment is 3, the decoder selects MS channel data as input, where the left and right channel signals are recovered using the following formula:

[0385] M′=2×M+(Smod2)

[0386]

[0387] Verification results from multiple representative stereo audio samples demonstrate that the embodiments of this disclosure significantly improve compression efficiency for biased-phase signals while maintaining lossless restoration capabilities. Some test comparison results are shown in Table 1. These results prove that, in biased-phase signal scenarios, the embodiments of this disclosure can effectively improve the compression ratio, exhibiting both good versatility and practical application value.

[0388] Table 1. Comparison of compression effects for biased and inverted signals

[0389]

[0390] This embodiment of the disclosure obtains the cross-correlation coefficient value by analyzing the cross-correlation of two channel signals, and adaptively selects the corresponding decorrelation processing method (i.e., method A or method B) according to a pre-set or adaptively set threshold. Method B is suitable for positively correlated signals with channel cross-correlation coefficients in the range [Thres1, 1]. Furthermore, this embodiment innovatively adds method A, which, when the channel cross-correlation coefficients are in the range [-1, Thres1), obtains the Mid and Sid channels through sum-difference downmixing to compress such signals more efficiently. Method selection information is transmitted by adding a flag bit to the bitstream header: flag = 0 indicates method A, flag = 1 indicates method B. The decoding end performs the corresponding inverse transform accordingly to losslessly recover the original stereo signal.

[0391] The embodiments disclosed herein ensure that while maintaining lossless restoration capability, full use is made of signal correlation and statistical characteristics to improve the compression rate of the phase-inverting signal encoding, thereby forming a complete solution for decorrelation of stereo signals.

[0392] In some embodiments of this disclosure, an encoding / decoding system is provided, which may include an encoder and a decoder, wherein the encoder may execute the encoding method performed by the encoder in the foregoing embodiments of this disclosure; and the decoder may execute the decoding method performed by the decoder in the foregoing embodiments of this disclosure.

[0393] This disclosure also provides embodiments of an apparatus for implementing any of the above methods. For example, an apparatus is provided that includes units or modules for implementing the steps performed by the encoder in any of the above methods. Furthermore, another apparatus is provided that includes units or modules for implementing the steps performed by the decoder in any of the above methods.

[0394] It should be understood that the division of units or modules in the above device is only a logical functional division. In actual implementation, they can be fully or partially integrated into a single physical entity, or they can be physically separated. Furthermore, the units or modules in the device can be implemented by a processor calling software: for example, the device includes a processor connected to a memory containing instructions. The processor calls the instructions stored in the memory to implement any of the above methods or to implement the functions of the units or modules in the above device. The processor can be, for example, a general-purpose processor, such as a Central Processing Unit (CPU) or a microprocessor, and the memory can be internal or external to the device. Alternatively, the units or modules in the device can be implemented in the form of hardware circuits. The functionality of some or all of the units or modules can be achieved through the design of these hardware circuits, which can be understood as one or more processors. For example, in one implementation, the hardware circuit is an Application-Specific Integrated Circuit (ASIC), and the functionality of some or all of the units or modules is achieved through the design of the logical relationships between the components within the circuit. In another implementation, the hardware circuit can be implemented using a Programmable Logic Device (PLD), such as a Field Programmable Gate Array (FPGA), which can include a large number of logic gates. The connection relationships between the logic gates are configured through configuration files, thereby achieving the functionality of some or all of the units or modules. All units or modules of the above device can be implemented entirely through processor-called software, entirely through hardware circuits, or partially through processor-called software with the remaining parts implemented through hardware circuits.

[0395] In this embodiment, the processor is a circuit with signal processing capabilities. In one implementation, the processor can be a circuit with instruction read and execute capabilities, such as a Central Processing Unit (CPU), a microprocessor, a Graphics Processing Unit (GPU) (which can be understood as a microprocessor), or a Digital Signal Processor (DSP). In another implementation, the processor can implement certain functions through the logical relationships of hardware circuits. The logical relationships of the aforementioned hardware circuits are fixed or reconfigurable. For example, the processor is a hardware circuit implemented using an Application-Specific Integrated Circuit (ASIC) or a Programmable Logic Device (PLD), such as an FPGA. In a reconfigurable hardware circuit, the process of the processor loading a configuration document and configuring the hardware circuit can be understood as the process of the processor loading instructions to implement the functions of some or all of the above units or modules. In addition, it can also be hardware circuits designed for artificial intelligence, which can be understood as ASICs, such as Neural Network Processing Units (NPUs), Tensor Processing Units (TPUs), and Deep Learning Processing Units (DPUs).

[0396] Figure 5A This is a schematic diagram of the structure of an encoding device according to an embodiment of this disclosure. Figure 5AAs shown, the encoding device 5100 may include at least one of a processing module 5101, a transceiver module 5102, etc. In some embodiments, the processing module 5101 is configured to select a downmixing processing strategy based on the correlation between the left channel signal and the right channel signal; determine the center channel signal and the side channel signal based on the selected downmixing processing strategy; and determine first encoded data based on the left channel signal, the right channel signal, the center channel signal, the side channel signal, and the selected downmixing processing strategy. Optionally, the transceiver module 5101 may be configured to perform at least one of the communication steps (e.g., steps S2110, S2210, but not limited thereto) performed by the encoder 101 in any of the above methods, which will not be described in detail here. Optionally, the processing module 5102 can be used to execute at least one of the other steps executed by the encoder 101 in any of the above methods (e.g., steps S2101, S2102, S2103, S2104, S2105, S2106, S2107, S2108, S2109, S2111, S2112, S2113, S2114, S2115, S2201, S2202, S2203, S2204, S2205, S2206, S2207, S2208, S2209, S2211, S2212, S2213, S2214, S2215, but not limited thereto), which will not be elaborated here.

[0397] Figure 5B This is a schematic diagram of the structure of a decoding device proposed in an embodiment of this disclosure. Figure 5BAs shown, the decoding device 5200 may include at least one of a processing module 5201 and a transceiver module 5202. In some embodiments, the processing module 5201 is used to decode the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain a left channel signal and a right channel signal; wherein, the downmixing processing strategy is selected by the encoder based on the correlation between the left channel signal and the right channel signal and used to determine the center channel signal and the side channel signal, and the second encoded data is encoded by the encoder according to the encoding method determined by the left channel signal, the right channel signal, the center channel signal, and the side channel signal. Optionally, the transceiver module 5101 may be used to perform at least one of the communication steps such as sending and / or receiving performed by the decoder 102 in any of the above methods (e.g., steps S2110, S2210, but not limited thereto), which will not be described in detail here. Optionally, the processing module 5102 can be used to execute at least one of the other steps executed by the decoder 102 in any of the above methods (e.g., steps S2101, S2102, S2103, S2104, S2105, S2106, S2107, S2108, S2109, S2111, S2112, S2113, S2114, S2115, S2201, S2202, S2203, S2204, S2205, S2206, S2207, S2208, S2209, S2211, S2212, S2213, S2214, S2215, but not limited thereto), which will not be elaborated here.

[0398] In some embodiments, the transceiver module may include a transmitting module and / or a receiving module, which may be separate or integrated. Optionally, the transceiver module may be interchangeable with a transceiver.

[0399] In some embodiments, the processing module may be a single module or may include multiple sub-modules. Optionally, the multiple sub-modules may each perform all or part of the steps required by the processing module. Optionally, the processing module may be interchangeable with a processor.

[0400] Figure 6AThis is a schematic diagram of the structure of a communication device 6100 according to an embodiment of this disclosure. The communication device 6100 can be an encoder, a decoder, a chip, chip system, or processor that supports the encoder in implementing any of the above methods, or a chip, chip system, or processor that supports the decoder in implementing any of the above methods. The communication device 6100 can be used to implement the methods described in the above method embodiments; for details, please refer to the descriptions in the above method embodiments.

[0401] like Figure 6A As shown, the communication device 6100 is used to execute any of the above methods. In some embodiments, the communication device 6100 includes one or more processors 6101. The processor 6101 may be a general-purpose processor or a special-purpose processor, such as a baseband processor or a central processing unit. The baseband processor may be used to process communication protocols and communication data, and the central processing unit may be used to control communication devices (e.g., base stations, baseband chips, terminal devices, terminal device chips, DUs or CUs, etc.), execute programs, and process program data. Optionally, the communication device 6100 is used to execute any of the above methods. Optionally, one or more processors 6101 are used to invoke instructions to cause the communication device 6100 to execute any of the above methods.

[0402] In some embodiments, the communication device 6100 further includes one or more transceivers 6102. When the communication device 6100 includes one or more transceivers 6102, the transceivers 6102 perform at least one of the communication steps such as sending and / or receiving in the above method (e.g., steps S2110, S2210, but not limited thereto), and the processor 6101 performs other steps (e.g., steps S2101, S2102, S2103, S2104, S2105, S2106, S2107, S2108, S2109, S210 ... Steps 109, S2111, S2112, S2113, S2114, S2115, S2201, S2202, S2203, S2204, S2205, S2206, S2207, S2208, S2209, S2211, S2212, S2213, S2214, and S2215 (but not limited thereto) are at least one of the following. In optional embodiments, the transceiver may include a receiver and / or a transmitter, which may be separate or integrated. Optionally, the terms transceiver, transceiver unit, transceiver, transceiver circuit, interface circuit, and interface can be used interchangeably; the terms transmitter, transmitting unit, transmitter, and transmitting circuit can be used interchangeably; and the terms receiver, receiving unit, receiver, and receiving circuit can be used interchangeably.

[0403] In some embodiments, the communication device 6100 further includes one or more memories 6103 for storing data and / or instructions. Optionally, one or more processors 6101 are used to invoke instructions stored in the memory 6103 to cause the communication device 6100 to perform any of the above methods. Optionally, all or part of the memory 6103 may also be located outside the communication device 6100. In an optional embodiment, the communication device 6100 may include one or more interface circuits 6104. Optionally, the interface circuit 6104 is connected to the memory 6103 and can be used to receive data and / or instructions from the memory 6103 or other devices, and can be used to send data and / or instructions to the memory 6103 or other devices. For example, the interface circuit 6104 can read data and / or instructions stored in the memory 6103 and send the data and / or instructions to the processor 6101.

[0404] The communication device 6100 described in the above embodiments may be a network device or a terminal, but the scope of the communication device 6100 described in this disclosure is not limited thereto, and the structure of the communication device 6100 may vary. Figure 6A The limitations. The communication device may be a standalone device or part of a larger device. For example, the communication device may be: (1) a standalone integrated circuit IC, or chip, or chip system or subsystem; (2) a collection of one or more ICs, optionally including storage components for storing data, programs and / or instructions; (3) an ASIC, such as a modem; (4) a module that can be embedded in other devices; (5) a receiver, terminal device, smart terminal device, cellular phone, wireless device, handheld device, mobile unit, vehicle device, network device, cloud device, artificial intelligence device, etc.; (6) others, etc.

[0405] Figure 6B This is a schematic diagram of the structure of chip 6200 according to an embodiment of this disclosure. For cases where the communication device 6100 can be a chip or a chip system, please refer to... Figure 6B The diagram shown is a schematic representation of the structure of chip 6200, but it is not limited to this.

[0406] Chip 6200 includes one or more processors 6201. Chip 6200 is used to perform any of the methods described above.

[0407] In some embodiments, chip 6200 further includes one or more interface circuits 6202. Optionally, terms such as interface circuit, interface, and transceiver pin can be used interchangeably. In some embodiments, chip 6200 further includes one or more memories 6203 for storing data and / or instructions. Optionally, all or part of the memories 6203 may be located outside of chip 6200. Optionally, interface circuit 6202 is connected to memory 6203, and interface circuit 6202 can be used to receive data and / or instructions from memory 6203 or other devices, and interface circuit 6202 can be used to send data and / or instructions to memory 6203 or other devices. For example, interface circuit 6202 can read data and / or instructions stored in memory 6203 and send the data and / or instructions to processor 6201.

[0408] In some embodiments, the interface circuit 6202 performs at least one of the communication steps such as sending and / or receiving in the above method (e.g., steps S2110, S2210, but not limited thereto). For example, the interface circuit 6202 performing the communication steps such as sending and / or receiving in the above method means that the interface circuit 6202 performs data and / or instruction interaction between the processor 6201, the chip 6200, the memory 6203, or the transceiver device. In some embodiments, the processor 6201 performs at least one of other steps (e.g., steps S2101, S2102, S2103, S2104, S2105, S2106, S2107, S2108, S2109, S2111, S2112, S2113, S2114, S2115, S2201, S2202, S2203, S2204, S2205, S2206, S2207, S2208, S2209, S2211, S2212, S2213, S2214, S2215, but is not limited thereto).

[0409] The modules and / or devices described in the various embodiments, such as virtual devices, physical devices, and chips, can be combined or separated arbitrarily as needed. Optionally, some or all steps can also be performed collaboratively by multiple modules and / or devices, which is not limited here.

[0410] This disclosure also proposes a storage medium storing instructions that, when executed on a communication device, cause the communication device to perform any of the above methods. Optionally, the storage medium is an electronic storage medium. Optionally, the storage medium is a computer-readable storage medium, but not limited thereto; it may also be a storage medium readable by other devices. Optionally, the storage medium may be a non-transitory storage medium, but not limited thereto; it may also be a temporary storage medium.

[0411] This disclosure also proposes a program product, including a program and / or instructions, which, when executed by a communication device, cause the communication device to perform any of the above methods. Optionally, the program product is a computer program product. Optionally, the program product is stored on the storage medium.

[0412] This disclosure also proposes a computer program that, when run on a computer, causes the computer to perform any of the above methods.

Claims

1. A stereo coding method, characterized in that, Performed by the encoder, the method includes: Select the downmixing processing strategy based on the correlation between the left and right channel signals; The center channel signal and side channel signals are determined based on the selected downmixing processing strategy; The first encoded data is determined based on the left channel signal, the right channel signal, the center channel signal, the side channel signal, and the selected downmixing strategy.

2. The method according to claim 1, characterized in that, The step of determining the first encoded data based on the left channel signal, the right channel signal, the center channel signal, the side channel signals, and the selected downmixing strategy includes: The encoding method is determined based on the left channel signal, the right channel signal, the center channel signal, and the side channel signals. The first encoded data is determined based on the encoding method, the second encoded data obtained by encoding based on the encoding method, and the selected downmixing processing strategy.

3. The method according to claim 1 or 2, characterized in that, The method of selecting a downmixing processing strategy based on the correlation between the left and right channel signals includes: Determine the cross-correlation coefficient between the left channel signal and the right channel signal; The undermixing processing strategy is selected based on the cross-correlation coefficient and the threshold.

4. The method according to claim 3, characterized in that, Determining the cross-correlation coefficient between the left channel signal and the right channel signal includes: The cross-correlation coefficient n is calculated using the following formula. LR : Where L represents the left channel signal, L i This represents the i-th sample point in the left channel signal. R represents the average value of n samples in the left channel signal, and R represents the right channel signal. i This represents the i-th sample point in the right channel signal. This represents the average value of n samples in the right channel signal.

5. The method according to claim 3 or 4, characterized in that, The step of selecting the downmixing processing strategy based on the cross-correlation coefficient and the threshold includes: If the cross-correlation coefficient is less than the threshold, the first downmixing processing strategy is selected; or... If the cross-correlation coefficient is greater than or equal to the threshold, the second downmixing processing strategy is selected.

6. The method according to claim 5, characterized in that, Determining the center channel signal and the side channel signals based on the first downmixing processing strategy includes: The center channel signal and the side channel signals are calculated using the following formula: M = L + R Wherein, M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

7. The method according to claim 6, characterized in that, The step of determining the encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signals includes: Determine the first number of bits required to encode the left channel signal and the right channel signal; Determine the second number of bits required to encode the left channel signal and the center channel signal; Determine the number of third bits required to encode the right channel signal and the center channel signal; Determine the number of fourth bits required to encode the center channel signal and the side channel signals; The encoding method is determined based on the minimum number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

8. The method according to claim 5, characterized in that, Determining the center channel signal and the side channel signals based on the second downmixing processing strategy includes: The center channel signal and the side channel signals are calculated according to the following formulas: S=LR Wherein, M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

9. The method according to claim 8, characterized in that, The step of determining the encoding method based on the left channel signal, the right channel signal, the center channel signal, and the side channel signals includes: Determine the first number of bits required to encode the left channel signal and the right channel signal; Determine the second number of bits required to encode the left channel signal and the side channel signal; Determine the third number of bits required to encode the right channel signal and the side channel signal; Determine the number of fourth bits required to encode the center channel signal and the side channel signals; The encoding method is determined based on the minimum number of bits among the first number of bits, the second number of bits, the third number of bits, and the fourth number of bits.

10. The method according to any one of claims 1-9, characterized in that, The method further includes: The first encoded data is sent to the decoder.

11. A stereo decoding method, characterized in that, The method, executed by the decoder, includes: The second encoded data in the first encoded data is decoded according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal; The downmixing processing strategy is that the encoder selects and uses the correlation between the left channel signal and the right channel signal to determine the center channel signal and the side channel signal. The second encoded data is encoded by the encoder according to the encoding method determined by the left channel signal, the right channel signal, the center channel signal, and the side channel signal.

12. The method according to claim 11, characterized in that, The step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: The downmixing processing strategy is either a first downmixing processing strategy or a second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the right channel signal, and the left channel signal and the right channel signal are obtained by decoding according to the second encoded data.

13. The method according to claim 11, characterized in that, The step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: The downmixing processing strategy is a first downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the center channel signal. The left channel signal and the center channel signal are obtained by decoding according to the second encoded data. The right channel signal is determined based on the left channel signal and the center channel signal using the following formula: R = ML Wherein, M represents the center channel signal, L represents the left channel signal, and R represents the right channel signal.

14. The method according to claim 11, characterized in that, The step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: The downmixing processing strategy is a first downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the center channel signal. The right channel signal and the center channel signal are obtained by decoding according to the second encoded data. The left channel signal is determined based on the right channel signal and the center channel signal using the following formula: L = MR Wherein, M represents the center channel signal, L represents the left channel signal, and R represents the right channel signal.

15. The method according to claim 11, characterized in that, The step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: The downmixing processing strategy is a first downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal. The center channel signal and the side channel signal are obtained by decoding according to the second encoded data. The left channel signal and the right channel signal are determined based on the center channel signal and the side channel signals using the following formula: S′=2×S+(Mmod2) Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, R represents the right channel signal, and mod represents the modulo operator.

16. The method according to claim 11, characterized in that, The step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: The downmixing processing strategy is the second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the left channel signal and the side channel signal. The left channel signal and the side channel signal are obtained by decoding according to the second encoded data. The right channel signal is determined based on the left channel signal and the side channel signal using the following formula: R = LS Wherein, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

17. The method according to claim 11, characterized in that, The step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: The downmixing processing strategy is the second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the right channel signal and the side channel signal. The right channel signal and the side channel signal are obtained by decoding according to the second encoded data. The left channel signal is determined based on the right channel signal and the side channel signal using the following formula: L = R + S Wherein, S represents the side channel signal, L represents the left channel signal, and R represents the right channel signal.

18. The method according to claim 11, characterized in that, The step of decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal includes: The downmixing processing strategy is the second downmixing processing strategy, and the encoding method indicates that the second encoded data is the encoding result of the center channel signal and the side channel signal. The center channel signal and the side channel signal are obtained by decoding according to the second encoded data. The left channel signal and the right channel signal are determined based on the center channel signal and the side channel signals using the following formula: M′=2×M+(Smod2) Where M represents the center channel signal, S represents the side channel signal, L represents the left channel signal, R represents the right channel signal, and mod represents the modulo operator.

19. The method according to any one of claims 11-18, characterized in that, Before decoding the second encoded data in the first encoded data according to the downmixing processing strategy and encoding method indicated in the first encoded data to obtain the left channel signal and the right channel signal, the process includes: Receive the first encoded data sent by the encoder.

20. An encoding device, characterized in that, The encoding device is used to perform the stereo encoding method according to any one of claims 1-10.

21. A decoding device, characterized in that, The decoding device is used to perform the stereo decoding method according to any one of claims 11-19.

22. A stereo encoding / decoding system, characterized in that, The method includes an encoder and a decoder, wherein the encoder is configured to implement the stereo encoding method according to any one of claims 1-10, and the decoder is configured to implement the stereo decoding method according to any one of claims 11-19.

23. A storage medium storing instructions, characterized in that, When the instructions are executed on the communication device, the communication device performs the method of any one of claims 1-19.

24. A program product comprising at least one of a program and instructions, characterized in that, When at least one of the programs or instructions is executed by a communication device, the method of any one of claims 1-19 is implemented.

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