CN112309408A - Method, device and storage medium for expanding LC3 audio encoding and decoding bandwidth - Google Patents
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Abstract
The invention discloses a method, a device and a storage medium for expanding LC3 audio coding and decoding bandwidth. The method mainly comprises the steps of dividing an audio signal into a first low-frequency band signal and a first high-frequency band signal by taking a preset frequency as a boundary; carrying out mirror image operation on the standard spectral coefficient obtained by transforming the first high-frequency band signal by using a mirror image module in a mirror image LC3 encoder to obtain a mirror image spectral coefficient; encoding the mirror spectral coefficients into high-frequency band code streams by using a standard LC3 encoding module in a mirror LC3 encoder; decoding the high-band code stream into mirror spectral coefficients using a standard LC3 decoding module in a mirror LC3 decoder; carrying out mirror image operation on the mirror image spectral coefficient by using a mirror image module in a mirror image LC3 decoder to obtain a standard spectral coefficient, and obtaining a decoding signal of the first high-frequency band signal by using inverse transformation and a filter; and synthesizing the decoded signal of the first low-frequency band signal and the decoded signal of the first high-frequency band signal to obtain a full-frequency band signal. The invention does not lose the high-frequency part when the code rate is middle and high, and improves the tone quality of the audio.
Description
Technical Field
The present invention relates to the field of audio coding technologies, and in particular, to a method, an apparatus, and a storage medium for expanding LC3 audio codec bandwidth.
Background
With the development of technology, bluetooth technology is widely used in the fields of telecommunications, computers, networks, consumer electronics, and the like.
Currently, mainstream Bluetooth audio encoders comprise SBC, AAC-LC, aptX series, LDAC and LHDC, wherein SBC has general sound quality, AAC-LC has good sound quality but occupies a large memory, the operation complexity is high, the aptX series and LDAC have good sound quality, but the code rate is high, the technology is closed, the LHDC has good sound quality, but the code rate is high, and the requirement on Bluetooth design is high.
For the above reasons, LC3 was introduced by the international bluetooth alliance in combination with many manufacturers, and LC3 has attracted much attention and is widely used because of its advantages of low delay, high sound quality, high coding gain and no special fee in the bluetooth field.
Subject to certain conditions, the standard LC3 codec loses some high frequency components when encoding compressed audio, which can impair the audio quality.
Disclosure of Invention
Aiming at the problems in the prior art, the invention mainly provides a method, a device and a storage medium for expanding LC3 audio coding and decoding bandwidth.
In order to achieve the above purpose, the invention adopts a technical scheme that: there is provided a method of extending LC3 audio codec bandwidth, comprising: dividing the audio signal into a first low-frequency band signal and a first high-frequency band signal with a predetermined frequency as a boundary; performing discrete cosine transform on the first high-frequency band signal to obtain a standard spectral coefficient, and performing mirror image operation on the standard spectral coefficient by using a mirror image module in a mirror image LC3 encoder to obtain a mirror image spectral coefficient; encoding the mirror spectral coefficients into high-frequency band code streams by using a standard LC3 encoding module in a mirror LC3 encoder; decoding the high-band code stream into mirror spectral coefficients using a standard LC3 decoding module in a mirror LC3 decoder; performing mirror image operation on the mirror image spectral coefficient by using a mirror image module in a mirror image LC3 decoder to obtain a standard spectral coefficient, and obtaining a decoding signal of a first high-frequency band signal by using inverse discrete cosine transform and a long-term post filter; synthesizing the decoded signal of the first low-frequency band signal and the decoded signal of the first high-frequency band signal to obtain a full-band audio signal; when the first high-frequency band signal is coded and decoded, the decoded signal of the first low-frequency band signal is obtained after the first low-frequency band signal is coded and decoded by the standard LC 3.
The invention adopts another technical scheme that: there is provided a device for extending LC3 audio codec bandwidth, comprising: means for dividing an audio signal into a first low-band signal and a first high-band signal bounded by a predetermined frequency; a module for performing discrete cosine transform on the first high-frequency band signal to obtain a standard spectral coefficient, and performing mirror image operation on the standard spectral coefficient by using a mirror image module in a mirror image LC3 encoder to obtain a mirror image spectral coefficient; a module for a standard LC3 encoding module in the mirror LC3 encoder to encode mirror spectral coefficients into a high-band codestream; a module for decoding the high-band code stream into mirror spectral coefficients using a standard LC3 decoding module in a mirror LC3 decoder; a module for performing mirror image operation on the mirror image spectral coefficient by using a mirror image module in the mirror image LC3 decoder to obtain a standard spectral coefficient, and obtaining a decoded signal of the first high-frequency band signal by using inverse discrete cosine transform and a long-term post-filter; a module for synthesizing the decoded signal of the first low-band signal and the decoded signal of the first high-band signal to obtain a full-band audio signal; the decoding signal of the first low-frequency band signal is obtained after the first low-frequency band signal is coded and decoded by standard LC3 when the first high-frequency band signal is coded and decoded.
The invention adopts another technical scheme that: there is provided a computer readable storage medium storing computer instructions operable to perform the method of extending LC3 audio codec bandwidth in scenario one.
The invention adopts another technical scheme that: there is provided a computer device comprising a processor and a memory, the memory storing computer instructions, the processor operating the computer instructions to perform the method of extending LC3 audio codec bandwidth in scheme one.
The technical scheme of the invention can achieve the following beneficial effects: the invention designs a method, a device and a storage medium for expanding LC3 audio coding and decoding bandwidth. According to the method, firstly, a mirror image LC3 encoder is used for converting a high-frequency band signal into a low-frequency band signal for encoding, then a mirror image LC3 decoder is used for converting the encoded low-frequency band signal into a decoded high-frequency band signal, and finally the decoded high-frequency band signal and the decoded low-frequency band signal are decoded and synthesized, so that the high-frequency component of the signal can not be lost when the medium-high code rate transmission of the Bluetooth signal is carried out, and the tone quality of the audio is improved.
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Fig. 1 is a schematic diagram of a first embodiment of a method for expanding LC3 audio codec bandwidth according to the present invention;
FIG. 2 is a diagram of a second embodiment of an apparatus for expanding LC3 audio codec bandwidth according to the present invention;
fig. 3 is a schematic diagram of an example of the method for expanding the audio codec bandwidth of the LC3 when the bandwidth of 24kHz is input.
Detailed Description
The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
Fig. 1 shows a first embodiment of the method for expanding the LC3 audio codec bandwidth according to the present invention.
In this embodiment, the method for extending the audio codec bandwidth of the LC3 mainly includes step S101, dividing the audio signal into a first low-frequency band signal and a first high-frequency band signal with a predetermined frequency as a boundary.
In an embodiment of the present invention, step S101 further includes that the first low-band signal and the first high-band signal are obtained by processing through a quadrature mirror filter analyzer.
In one embodiment of the present invention, the input audio signal is processed by a low-pass filter and a high-pass filter in a quadrature mirror filter analyzer to obtain two frequency band signals with equal frequency band width.
For example, an audio signal with a bandwidth of 24kHz is input to a quadrature mirror filter analyzer, and after being processed by the quadrature mirror filter analyzer, a low-frequency band signal (20Hz to 12kHz) and a high-frequency band signal (12kHz to 24kHz) are obtained.
The specific embodiment separates the high-frequency band signal from the input audio signal, and lays a foundation for the transmission of the high-frequency band signal in the LC 3.
In the specific embodiment shown in fig. 1, the method for expanding the LC3 audio codec bandwidth further includes step S102, performing discrete cosine transform on the first high-frequency band signal to obtain a standard spectral coefficient, and performing a mirror image operation on the standard spectral coefficient by using a mirror image module in a mirror image LC3 encoder to obtain a mirror image spectral coefficient.
In a specific embodiment of the present invention, the standard spectral coefficients of the first high-frequency band signal are obtained by transforming the first high-frequency band signal in the mirror LC3 encoder through the low-delay modified discrete cosine transform module, and the mirror module in the mirror LC3 encoder processes the standard spectral coefficients at the mirror axis through mirror processing, so as to convert the standard spectral coefficients with high-frequency characteristics into mirror spectral coefficients with low-frequency characteristics without changing the amplitude-frequency characteristics of the standard spectral coefficients of the first high-frequency band signal.
The specific embodiment converts the signal with high-frequency characteristic into the signal with low-frequency characteristic, so that the image LC3 encoder can encode the signal with high-frequency band component, the high-frequency band component of the audio signal can not be lost in the Bluetooth encoding transmission process, and a foundation is provided for expanding LC3 audio codec bandwidth.
In the embodiment shown in fig. 1, the method for expanding the LC3 audio codec bandwidth further includes step S103, encoding the mirror spectral coefficients into a high-band code stream by using a standard LC3 encoding module in a mirror LC3 encoder.
In one embodiment of the present invention, the mirror module in the mirror LC3 encoder is located between the low-latency modified discrete cosine transform module and the transform domain noise shaping module of the mirror LC3 encoder.
In the prior art, in a standard LC3 encoder, an input audio signal is subjected to data compression by a low-delay improved discrete cosine transform module and then directly enters a transform domain noise shaping module, a time domain noise shaping module, a quantization module, a noise level estimation module and an arithmetic coding processing module to obtain a standard low-frequency band code stream. In the invention, a mirror module is added between the low-delay improved discrete cosine transform module and the transform domain noise shaping module.
In the mirror image LC3 encoder, the high-frequency band signal is subjected to time-frequency conversion through low-delay modified discrete cosine transform, the converted data is subjected to frequency spectrum mirror image to obtain a mirror image processed low-frequency band signal, and then the mirror image processed low-frequency band signal is subjected to transform domain noise shaping, time domain noise shaping, quantization, noise level estimation and arithmetic coding in sequence to obtain a mirror image high-frequency band code stream.
For example, as shown in fig. 3, the low-band pulse code modulation signal (20Hz to 12kHz) and the high-band pulse code modulation signal (12kHz to 24kHz) are respectively called a standard LC3 encoder and a mirror LC3 encoder to obtain a low-band code stream and a high-band code stream, where the nyquist frequency in the figure is the effective bandwidth of the original audio.
The specific embodiment ensures that the high-frequency part of the audio signal cannot be omitted when the audio signal is transmitted, ensures the integrity of the audio signal and improves the tone quality of the audio.
In a specific example of the present invention, after the first low-frequency band signal and the first high-frequency band signal are encoded, a standard code stream of the first low-frequency band signal and a high-frequency band code stream of the first high-frequency band signal are obtained, and the two encoded signals are transmitted in a bluetooth manner.
According to the specific embodiment, short-distance wireless communication can be achieved, and data transmission is more convenient.
In the embodiment shown in fig. 1, the method for expanding the LC3 audio codec bandwidth further includes step S104, decoding the high-band code stream into the mirror spectral coefficients by using a standard LC3 decoding module in a mirror LC3 decoder.
In an embodiment of the present invention, after the mirror LC3 decoder receives the encoded data from the mirror LC3 encoder, the received high-band code stream of the first high-band signal is subjected to arithmetic and residual coding, noise padding, global gain, time domain noise shaping decoding, transform domain noise shaping decoding, and the like, so as to obtain the mirror spectral coefficients of the first high-band signal.
The specific embodiment is the basis for realizing that high frequency components are not lost when high code rate is high in transmission in LC3 audio transmission.
In the embodiment shown in fig. 1, the method for expanding the LC3 audio codec bandwidth further includes step S105, performing a mirror operation on the mirror spectral coefficients by using a mirror module in the mirror LC3 decoder to obtain standard spectral coefficients, and obtaining a decoded signal of the first high-band signal by using an inverse discrete cosine transform and a long-term post filter.
In one embodiment of the present invention, the mirror module in the mirror LC3 decoder is located between the transform domain noise shaping decoding module and the low-latency inverse modified discrete cosine transform module of the mirror LC3 decoder.
In the prior art, a standard LC3 decoder processes a received low-frequency band decoded signal stream sequentially through an arithmetic and residual decoding module, a noise filling module, a global gain module, a time domain noise shaping decoding module, a transform domain noise shaping decoding module, and a low-delay improved inverse discrete cosine transform module to obtain a low-frequency band decoded signal.
The mirror image LC3 decoder makes the high frequency band code stream pass through the arithmetic and residual decoding module, the noise filling module, the global gain module, the time domain noise shaping decoding module and the transform domain noise shaping decoding module in sequence to obtain the mirror image spectral coefficient, and the mirror image spectral coefficient is processed by the mirror image module and the low delay improved inverse discrete cosine transform module to obtain the high frequency band signal.
For example, the bluetooth receiver receives the high-band code stream and the low-band code stream and respectively calls a standard LC3 decoder and a mirror LC3 decoder to generate a low-band decoded signal (20 Hz-12 kHz) and a high-band decoded signal (12 kHz-24 kHz).
This particular embodiment restores the high-band code stream formed by the mirrored LC3 encoder to a high-band decoded signal, ensuring the integrity of the audio signal.
In the specific embodiment shown in fig. 1, the method for expanding the LC3 audio codec bandwidth further includes step S106, synthesizing the decoded signal of the first low-band signal and the decoded signal of the first high-band signal to obtain a full-band audio signal; when the first high-frequency band signal is coded and decoded, the decoded signal of the first low-frequency band signal is obtained after the first low-frequency band signal is processed by standard LC3 coding and decoding.
In a specific embodiment of the present invention, when the mirror LC3 encoder and the mirror LC3 encoder/decoder perform encoding/decoding on the first high frequency band signal, the standard LC3 encoder and the standard LC3 encoder/decoder also perform encoding/decoding on the first low frequency band signal at the same time, and after the first low frequency band code stream and the first high frequency band code stream are decoded, the decoded signal of the first low frequency band code stream and the decoded signal of the first high frequency band code stream are synthesized.
The specific embodiment realizes that high-frequency components are not lost when high-code rate is transmitted by using the Bluetooth signals under the condition of small change, and provides better experience for users.
In an embodiment of the present invention, the step S106 further includes synthesizing the first low band decoded signal and the first high band decoded signal by a quadrature mirror synthesis filter.
In one embodiment of the present invention, the quadrature mirror synthesis filter synthesizes the first low band decoded signal and the first high band decoded signal, and restores the signals to the original bandwidth audio signal.
For example, the low band decoded signal (20Hz to 12kHz) and the high band decoded signal (12kHz to 24kHz) are passed through a quadrature mirror synthesis filter to obtain an audio signal with a bandwidth of 24 kHz.
According to the specific embodiment, the LC3 audio coding and decoding bandwidth is expanded, the audio quality is improved, and the bandwidth matching problem of the LC3 during audio coding and decoding is solved.
In a specific embodiment of the present invention, the mirroring refers to exchanging the high-frequency spectral coefficient and/or the low-frequency spectral coefficient under the condition that only the frequency characteristic of the high-frequency spectral coefficient and/or the low-frequency spectral coefficient is changed and other characteristics of the spectral coefficient are not changed, so as to obtain the corresponding mirrored low-frequency spectral coefficient and/or mirrored high-frequency spectral coefficient.
In particular, given spectral coefficients x (k), k 0F-1, wherein NFThe size of the audio frame specified for the LC3 standard; its mirror image module Y (k) X (N)F-1-k)，k＝0.....NF-1. Wherein, x (k) is the spectral coefficient of the audio subjected to discrete cosine transform in the encoding process, and the size of k represents the high and low frequency, i.e. when k is below a predetermined frequency threshold, x (k) represents the spectral coefficient of the low frequency; when k is above a predetermined frequency threshold, x (k) represents high frequency spectral coefficients.
Y (K) ═ X (Nf-1-K) denotes that the high spectral coefficient and the low spectral coefficient are exchanged without changing the spectral coefficient, so as to achieve the purpose of mirroring the high spectral coefficient to the low spectral coefficient and mirroring the low spectral coefficient to the high spectral coefficient;
in the embodiment shown in fig. 1, firstly, a high-frequency band signal is converted into a low-frequency band encoded signal by using an image LC3 encoder, and the encoded signal is encoded to obtain a high-frequency band code stream, then the high-frequency band code stream is converted into a high-frequency band decoded signal by using an image LC3 decoder, and finally the high-frequency band decoded signal and the low-frequency band decoded signal are synthesized, so that the high-frequency component of the signal is not lost when the medium and high code rate transmission of the bluetooth signal is performed, and the sound quality of the audio is improved.
Fig. 2 shows an embodiment of an apparatus for expanding LC3 audio codec bandwidth according to the present invention.
In this embodiment, the apparatus for expanding the LC3 audio codec bandwidth mainly includes: a module 201 for dividing the audio signal into a first low-band signal and a first high-band signal bounded by a predetermined frequency;
a module 202, configured to perform discrete cosine transform on the first high-frequency band signal to obtain a standard spectral coefficient, and perform mirror image operation on the standard spectral coefficient by using a mirror image module in a mirror image LC3 encoder to obtain a mirror image spectral coefficient;
a module 203 for encoding the mirror spectral coefficients into a high-band codestream using a standard LC3 encoding module in the mirror LC3 encoder;
a module 204 for decoding the high-band code stream into the mirror spectral coefficients using a standard LC3 decoding module in a mirror LC3 decoder;
a module 205 for performing a mirror operation on the mirror spectral coefficients by using a mirror module in the mirror LC3 decoder to obtain the standard spectral coefficients, and obtaining a decoded signal of the first high-band signal by using an inverse discrete cosine transform and a long-term post filter;
a module 206 for synthesizing a decoded signal of a first low-band signal with a decoded signal of the first high-band signal to obtain a full-band audio signal;
and the decoding signal of the first low-frequency band signal is obtained after the first low-frequency band signal is coded and decoded by standard LC3 when the first high-frequency band signal is coded and decoded.
The LC3 audio codec bandwidth extension apparatus provided in the present invention can be used to implement the LC3 audio codec bandwidth extension method described in any of the above embodiments, and the implementation principle and technical effect are similar, which are not described herein again.
In an embodiment of the present invention, the functional modules in the apparatus for expanding the audio codec bandwidth of the LC3 according to the present invention may be directly in hardware, in a software module executed by a processor, or in a combination of the two.
A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium.
The Processor may be a Central Processing Unit (CPU), other general-purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), other Programmable logic devices, discrete Gate or transistor logic, discrete hardware components, or any combination thereof. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
In another embodiment of the present invention, a computer readable storage medium stores computer instructions operable to perform the method of extending LC3 audio codec bandwidth in scenario one.
In another embodiment of the present invention, a computer device comprises a processor and a memory, the memory storing computer instructions, the processor operating the computer instructions to perform the method of expanding LC3 audio codec bandwidth in scenario one.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to other related technical fields, are included in the scope of the present invention.
Claims (9)
1. A method for expanding LC3 audio coding and decoding bandwidth, comprising:
dividing the audio signal into a first low-frequency band signal and a first high-frequency band signal with a predetermined frequency as a boundary;
performing discrete cosine transform on the first high-frequency band signal to obtain a standard spectral coefficient, and performing mirror image operation on the standard spectral coefficient by using a mirror image module in a mirror image LC3 encoder to obtain a mirror image spectral coefficient;
encoding the mirror spectral coefficients into a high-band codestream using a standard LC3 encoding module in the mirror LC3 encoder;
decoding the high-band code stream into the mirror spectral coefficients using a standard LC3 decoding module in a mirror LC3 decoder;
performing mirror image operation on the mirror image spectral coefficient by using a mirror image module in the mirror image LC3 decoder to obtain the standard spectral coefficient, and obtaining a decoding signal of the first high-frequency band signal by using inverse discrete cosine transform and a long-term post filter;
synthesizing a decoded signal of a first low-frequency band signal and a decoded signal of a first high-frequency band signal to obtain a full-band audio signal;
when the first high-frequency band signal is coded and decoded, the decoded signal of the first low-frequency band signal is obtained after the first low-frequency band signal is processed by standard LC3 coding and decoding.
2. The method for extending the audio codec bandwidth of LC3, according to claim 1, wherein the process of dividing the audio signal into a first low-band signal and a first high-band signal bounded by a predetermined frequency further comprises:
dividing the audio signal into the first low-band signal and the first high-band signal by a quadrature image analysis filter.
3. The method of extending the LC3 audio codec bandwidth of claim 1, wherein the mirror module in the mirror LC3 encoder is located between a low-latency modified discrete cosine transform module and a transform domain noise shaping module of the mirror LC3 encoder.
4. The method for extending the audio codec bandwidth of LC3, according to claim 1, wherein the synthesizing the decoded signal of the first low-band signal with the decoded signal of the second high-band signal further comprises:
and synthesizing the decoded signal of the first low-frequency band signal and the decoded signal of the first high-frequency band signal through a quadrature mirror synthesis filter.
5. The method for extending the audio codec bandwidth of LC3 according to claim 1, wherein a mirror module in the mirror LC3 decoder is located between a transform domain noise shaping decoding module and a low-latency inverse modified discrete cosine transform module of the mirror LC3 decoder.
6. The method of extending LC3 audio codec bandwidth of claim 1,
the mirror image refers to that the high-frequency spectral coefficient and/or the low-frequency spectral coefficient are exchanged under the condition that the frequency characteristic is only changed and other characteristics of the spectral coefficient are not changed, so that the corresponding mirror image low-frequency spectral coefficient and/or mirror image high-frequency spectral coefficient are obtained.
7. An apparatus for extending the audio codec bandwidth of LC3, comprising:
means for dividing an audio signal into a first low-band signal and a first high-band signal bounded by a predetermined frequency;
a module for performing discrete cosine transform on the first high-frequency band signal to obtain a standard spectral coefficient, and performing mirror image operation on the standard spectral coefficient by using a mirror image module in a mirror image LC3 encoder to obtain a mirror image spectral coefficient;
means for encoding the mirrored spectral coefficients into a high-band codestream using a standard LC3 encoding module in the mirrored LC3 encoder;
means for decoding the high-band code stream into the mirror spectral coefficients using a standard LC3 decoding module in a mirror LC3 decoder;
a module for performing a mirror image operation on the mirror image spectral coefficients by using a mirror image module in the mirror image LC3 decoder to obtain the standard spectral coefficients, and obtaining a decoded signal of the first high-frequency band signal by using inverse discrete cosine transform and a long-term post-filter;
for synthesizing a decoded signal of a first low-band signal with a decoded signal of the first high-band signal. A module for obtaining full-band audio signals;
and the decoding signal of the first low-frequency band signal is obtained after the first low-frequency band signal is coded and decoded by standard LC3 when the first high-frequency band signal is coded and decoded.
8. A computer readable storage medium storing computer instructions, wherein the computer instructions are operable to perform the method of extending LC3 audio codec bandwidth of any of claims 1-7.
9. A computer device comprising a processor and a memory, the memory storing computer instructions, wherein:
the processor operates the computer instructions to perform the method of extending LC3 audio codec bandwidth of any of claims 1-7.
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