An audio recording and conversion method for a Bluetooth headset

Abstract

The present invention discloses an audio recording and conversion method for a Bluetooth headset, specifically related to the field of audio recording and conversion. The present invention pairs and connects with the Bluetooth headset by turning on the Bluetooth function of the sound source device; subsequently, the recording process is started by pressing the "Recording" button on the headset, and the system guides the user to select the audio format and confirm the recording settings; during recording, the built-in microphone of the headset collects audio signals in real time, denoises and amplifies the collected audio signals, and then converts the processed audio signals into digital signals; the processed digital signals are embedded with watermarks, and the watermark evaluation value is calculated, and the watermark is verified by comparing the watermark evaluation value; then, the digital signals are converted into analog signals and reconstructed into audio signals, and finally, the system performs watermark detection on the reconstructed audio signals, and ensures the integrity and authenticity of the audio signal data by comparing the detected watermark information.

Description

Technical Field

[0001] The present invention relates to the technical field of audio recording conversion, and more specifically, to an audio recording and conversion method for a Bluetooth headset. Background Art

[0002] In today's fast-paced digital age, Bluetooth headsets, as the representative of personal audio devices, have penetrated into every aspect of our lives, from daily commuting to sports and fitness, to remote work and online education. Bluetooth headsets have won a broad user base with their convenience, wireless freedom and high-quality sound performance; however, with the advancement of technology and the diversification of application scenarios, users' functional demands for Bluetooth headsets are also growing, especially in terms of audio security conversion and management, which has become an important issue that needs to be urgently addressed.

[0003] However, in actual use, traditional Bluetooth headset audio recording still has some shortcomings. For example, traditional Bluetooth headsets mainly focus on the stability and sound quality of audio transmission, and have obvious deficiencies in the confidentiality of converted audio recording data. Summary of the invention

[0004] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides an audio recording and conversion method for a Bluetooth headset to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] Step A1: Turn on the Bluetooth function of the audio source device, pair it via Bluetooth, and confirm the recording settings;

[0007] Step A2: During the recording process, the built-in microphone of the Bluetooth headset collects audio signals in real time, and processes the collected audio signals to obtain digital signals;

[0008] Step A3: embedding the processed digital signal into a watermark, and calculating a watermark evaluation value based on the embedded watermark;

[0009] Step A4: converting the watermarked digital signal into an analog signal and reconstructing the audio signal;

[0010] Step A5: Perform watermark detection on the reconstructed audio signal and compare the detected watermarks.

[0011] Preferably, in step A1, after the sound source device turns on Bluetooth, ensure that it is in a "discoverable" state so that nearby Bluetooth devices can search for it; for the Bluetooth audio device to be connected, enter the pairing mode according to the instructions in the instruction manual; in the Bluetooth settings page of the sound source device, click "Search for Devices" to let the device start scanning for nearby Bluetooth devices; in the scan results, find the name of the Bluetooth audio device to be connected and click on it.

[0012] The user gently touches the "Recording" dedicated button on the Bluetooth headset, and the built-in microphone of the Bluetooth headset is immediately activated to prepare to receive sound signals; at the same time, the Bluetooth headset sends a recording start signal to the paired smart device via Bluetooth connection. After the paired smart device receives the recording start signal, a recording application notification immediately pops up on the screen; the system prompts the user in a friendly interface and clear language: "Recording is about to start. Please select the audio format you desire;". The user selects the WAV audio format from the options provided on the interface according to their needs. After selecting the audio format, the system will display an overview of the current recording settings; the user needs to carefully check these settings to ensure they meet their requirements; if modifications are needed, the user clicks on the corresponding option to make adjustments; when the recording settings are determined, the user clicks the "Start Recording" button, and the system starts recording according to the set parameters.

[0013] Preferably, in step A2, the collected audio signal is subjected to signal amplification and noise reduction processing. The method of noise reduction processing is specifically as follows:

[0014] Step B1 preprocesses the collected audio signal. The preprocessing includes removing the DC component and applying a window function at the front end of the signal to reduce the noise impact during processing;

[0015] Step B2: Use the fast Fourier transform to convert the time-domain signal into a frequency-domain representation; after obtaining the spectrum, represent the spectrum as an amplitude spectrum and a phase spectrum;

[0016] Step B3: Select a section that does not contain the useful signal for noise estimation; calculate the spectrum of the noise section to obtain the amplitude spectrum of this section;

[0017] In this step, apply smoothing processing to the spectrum of the noise to obtain a more stable noise model;

[0018] Step B4: Perform spectral subtraction on the amplitude spectrum of the original signal to obtain a second amplitude spectrum. The calculation method of the second amplitude spectrum is specifically as follows:

[0019] , where, represents the second amplitude spectrum obtained after removing the noise, represents the estimated noise amplitude spectrum; represents the amplitude spectrum of the noise signal, is expressed as a subtraction factor for further reducing residual noise; max is expressed as being used to compare two values and select the larger one;

[0020] Step B5: By combining the denoised amplitude spectrum with the phase spectrum of the original signal, a new spectrum is constructed. The specific calculation method of the new spectrum is as follows:

[0021] , where is expressed as the constructed new spectrum, is expressed as the second amplitude spectrum obtained after removing noise, is expressed as the phase spectrum representing the original noisy signal, is expressed as the phase angle of the a-th frequency component;

[0022] Step B6: Use the inverse fast Fourier transform to convert the denoised spectrum back to the time domain to obtain the processed audio signal.

[0023] The specific method for amplifying the audio signal is as follows:

[0024] Step C1: Convert the denoised audio signal into an electrical signal.

[0025] This electrical signal is usually very weak and may only be recognizable by delicate electronic components.

[0026] Step C2: The weak audio signal enters the preamplifier, and the preamplifier raises the intensity of the weak signal to a processable level;

[0027] Step C3: The preamplifier has a gain adjustment function, and the user sets the gain value according to needs.

[0028] Among them, the gain refers to the ratio of signal amplification, and a reasonable gain setting ensures that the audio signal will not be overly distorted or introduce noise;

[0029] Step C4: The amplified signal undergoes subsequent digital signal processing, and the signal is further clarified, and various audio effects are applied.

[0030] Preferably, in the said Step A3, after embedding the digital signal with the watermark, the specific calculation method of the watermark evaluation value and the watermark stability value is as follows:

[0031] , where is expressed as the watermark stability value, X is expressed as the correlation coefficient, I is expressed as the watermark evaluation value in the frequency domain, and D is expressed as the first capacity value;

[0032] The specific calculation method of the watermark sampling ratio is as follows:

[0033] , where Z represents the watermark sampling ratio, represents the sampling value of the host audio signal before watermark embedding, represents the sampling value of the host audio signal after watermark embedding, and T represents the total number of samplings;

[0034] The specific calculation method of the watermark evaluation value is as follows:

[0035] , where Q represents the watermark evaluation value, X represents the correlation coefficient, and Z represents the watermark sampling ratio, represents the watermark stability value.

[0036] Preferably, in step A4, select a DAC device, set the reference voltage, output range, and resolution of the DAC, and extract the converted digital signal; write the prepared digital signal value into the data input register of the DAC and wait for the conversion to start; according to the design of the DAC, the conversion is triggered by an external signal. During the conversion process, ensure that the clock signal of the DAC is correct so that the digital signal can be converted as planned;

[0037] After the DAC completes the conversion, a stable analog signal is obtained at the output; this process is affected by the settling time of the DAC; the output analog signal is smoothed by a filter to obtain a more natural audio waveform. After passing through the DAC and the filter, the signal is converted into a continuous analog waveform, and the continuous analog waveform is the reconstructed audio signal.

[0038] Preferably, in step A5, extract the watermark information from the reconstructed audio signal, calculate the extracted watermark information, and obtain the watermark similarity value. The specific calculation method of the watermark similarity value is as follows:

[0039] , where V represents the watermark similarity value, S represents the sample point, represents the number of audio frames, represents the amplitude value of the f-th frequency point in the e-th frame of the audio;

[0040] Calculate according to the calculated watermark similarity value. If the calculated watermark similarity value is equal to the preset watermark similarity value threshold, output a security instruction and store the audio signal in the built-in memory of the Bluetooth headset; if the calculated watermark similarity value is not equal to the preset watermark similarity value threshold, output a danger instruction and go to step A2.

[0041] The technical effects and advantages of the present invention:

[0042] The present invention provides an audio recording and conversion method for a Bluetooth headset. By pairing and connecting with a sound source device via Bluetooth, it supports directly operating the recording on the Bluetooth headset and selecting the audio format. The system will automatically process and embed a watermark into the recorded audio signal, and then convert the digital signal into an analog signal to reconstruct the audio output. Finally, the system will perform a watermark detection on the reconstructed audio to ensure the security and integrity of the audio data. This method enhances the confidentiality and security of the recording data, and the quality of the reconstructed audio signal is high, providing a more natural and realistic auditory experience for users. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] Please refer to Figure 1 As shown, the present invention provides an audio recording and conversion method for a Bluetooth headset, including the following steps:

[0046] Step A1: Turn on the Bluetooth function of the sound source device, pair and connect via Bluetooth, and confirm the recording settings;

[0047] In the said step A1, after the sound source device turns on Bluetooth, ensure that it is in a "discoverable" state so that nearby Bluetooth devices can search for it; for the Bluetooth audio device to be connected, enter the pairing mode according to the instructions in the instruction manual; in the Bluetooth settings page of the sound source device, click "Search for Devices" to let the device start scanning for nearby Bluetooth devices; in the scan results, find the name of the connected Bluetooth audio device and click it. At this time, the sound source device and the Bluetooth audio device establish a connection.

[0048] When the user gently touches the "Recording" dedicated button on the Bluetooth headset, the built-in microphone of the Bluetooth headset is immediately activated and ready to receive sound signals. At the same time, the Bluetooth headset sends a recording start signal to the paired smart device via Bluetooth connection. After receiving the recording start signal, a recording application notification immediately pops up on the screen of the paired smart device. The system prompts the user in a friendly interface and clear language: "Recording is about to start. Please select the audio format you desire." The user selects the WAV audio format from the options provided on the interface according to their needs. After selecting the audio format, the system will display an overview of the current recording settings. The user needs to carefully check these settings to ensure they meet their requirements. If modifications are needed, the user clicks on the corresponding option to make adjustments. When the recording settings are determined, the user clicks the "Start Recording" button, and the system starts recording according to the set parameters.

[0049] Among them, the recording setting parameters include the selected format, recording quality, and whether to enable the noise reduction function. The WAV format can maintain high audio quality.

[0050] Step A2: During the recording process, the built-in microphone of the Bluetooth headset continuously collects audio signals and processes the collected audio signals to obtain digital signals.

[0051] In the said Step A2, the collected audio signals are subjected to signal amplification and noise reduction processing. The method of noise reduction processing is specifically as follows:

[0052] Step B1 preprocesses the collected audio signals. The preprocessing includes removing the DC component and applying a window function at the front end of the signal to reduce the noise impact during processing.

[0053] Step B2: Use the fast Fourier transform to convert the time-domain signal into a frequency-domain representation. After obtaining the spectrum, represent the spectrum as an amplitude spectrum and a phase spectrum.

[0054] Step B3: Select a section that does not contain useful signals for noise estimation. Calculate the spectrum of the noise section to obtain the amplitude spectrum of this section.

[0055] In this step, smooth processing is applied to the spectrum of the noise to obtain a more stable noise model.

[0056] Step B4: Perform spectral subtraction on the amplitude spectrum of the original signal to obtain a second amplitude spectrum. The calculation method of the second amplitude spectrum is specifically as follows:

[0057] , where represents the second amplitude spectrum obtained after removing the noise, represents the estimated noise amplitude spectrum; represents the amplitude spectrum of the noise signal, is expressed as a subtraction factor for further reducing the residual noise; max is expressed as for comparing two values and selecting the larger one;

[0058] Step B5: By combining the denoised amplitude spectrum with the phase spectrum of the original signal, a new spectrum is constructed. The specific calculation method of the new spectrum is as follows:

[0059] , where is expressed as the constructed new spectrum, is expressed as the second amplitude spectrum obtained after removing noise, is expressed as the phase spectrum representing the original noisy signal, is expressed as the phase angle of the a-th frequency component;

[0060] Step B6: Use the inverse fast Fourier transform to convert the denoised spectrum back to the time domain to obtain the processed audio signal;

[0061] Perform sound detection on the denoised audio. Determine whether there is sound in the denoised audio through the audio confirmation value. The specific calculation method of the audio confirmation value is as follows:

[0062] , where R is expressed as the audio confirmation value, is expressed as the amplitude value of the f-th frequency point in the e-th frame, H is expressed as the total number of audio frames, is expressed as the length of the spectrum window, is expressed as the upper limit of the frequency point amplitude value, is expressed as the lower limit of the frequency point amplitude value;

[0063] Perform frame division and windowing on the preprocessed audio signal to be measured. Use a frame length of 32 milliseconds, a frame shift of 16 milliseconds, and apply a Hamming window; then perform a Fourier transform of 8192 points to obtain the audio signal to be measured;

[0064] Frame division and windowing: Divide the audio signal into continuous frames, each frame with a length of 32 milliseconds, and there is an overlap of 16 milliseconds (frame shift) between adjacent frames. This is done to capture the time-varying characteristics of the signal when analyzing the audio signal.

[0065] Hamming windowing: To reduce spectral leakage, each frame is multiplied by a Hamming window function. The Hamming window is a commonly used window function that can provide better frequency resolution and lower sidelobe levels in the frequency domain;

[0066] Fourier transform: Perform an 8192-point Fourier transform on each windowed frame, which converts the audio signal from the time domain to the frequency domain to obtain the spectral signal.

[0067] The specific calculation method of

[0068] , where represents the amplitude value of the f-th frequency point of the e-th frame, and T represents the harmonic value. represents the length of the spectral window;

[0069] Compare the calculated audio confirmation value with the preset audio confirmation value threshold. If the calculated audio confirmation value is greater than the preset audio confirmation value threshold, it is determined that there is sound in the audio; if the calculated audio confirmation value is less than the preset audio confirmation value threshold, it is determined that there is no sound in the audio.

[0070] The method for amplifying the audio signal is specifically as follows:

[0071] Step C1: Convert the denoised audio signal into an electrical signal.

[0072] This electrical signal is usually very weak and may only be recognizable by delicate electronic components.

[0073] Step C2: The weak audio signal enters the preamplifier, and the preamplifier raises the intensity of the weak signal to a processable level;

[0074] Step C3: The preamplifier has a gain adjustment function, and the user sets the gain value according to needs.

[0075] Among them, the gain refers to the ratio of signal amplification, and a reasonable gain setting ensures that the audio signal will not be overly distorted or introduce noise;

[0076] Step C4: The amplified signal undergoes subsequent digital signal processing, and the signal is further clarified, and various audio effects are applied.

[0077] Step A3: Embed a watermark in the processed digital signal and calculate the watermark evaluation value according to the embedded watermark;

[0078] In the above-mentioned step A3, after embedding the watermark in the digital signal, calculate the watermark evaluation value. The specific calculation method of the first capacity value is as follows:

[0079] , where D represents the first capacity value, E represents the bandwidth of the audio carrier signal, J represents the watermark efficiency, and K represents the attack power;

[0080] The specific calculation method of the frequency-domain watermark evaluation value is as follows:

[0081] I , where I represents the frequency-domain watermark evaluation value, represents the sampling frequency of the audio signal, represents the number of watermark bits embedded in each audio frequency domain segment, Represents the length of the audio time domain segment, Represents the number of audio time domain segments, Represents the number of audio frequency domain segments;

[0082] The specific calculation method of the correlation coefficient is as follows:

[0083] , where X represents the correlation coefficient, t represents the bit value of the original watermark, Represents the detected watermark bit value;

[0084] The specific calculation method of the watermark stability value is as follows:

[0085] , where, Represents the watermark stability value, X represents the correlation coefficient, I represents the frequency domain watermark evaluation value, D represents the first capacity value;

[0086] The specific calculation method of the watermark sampling ratio is as follows:

[0087] , where Z represents the watermark sampling ratio, Represents the sampling value of the host audio signal before watermark embedding, Represents the sampling value of the host audio signal after watermark embedding, T represents the total number of samplings;

[0088] The specific calculation method of the watermark evaluation value is as follows:

[0089] , where Q represents the watermark evaluation value, X represents the correlation coefficient, Z represents the watermark sampling ratio, Represents the watermark stability value;

[0090] Compare the calculated watermark evaluation value with the preset watermark evaluation threshold. If the calculated watermark evaluation value is greater than the preset watermark evaluation threshold, output a success instruction and go to step A5; if the calculated watermark evaluation value is less than the preset watermark evaluation threshold, output a failure instruction and re-embed the watermark.

[0091] Step A4: Convert the digital signal after watermark embedding into an analog signal and reconstruct the audio signal;

[0092] In the said step A4, select a DAC device, set the reference voltage, output range, and resolution of the DAC, and extract the conversion digital signal; write the prepared digital signal value into the data input register of the DAC and wait for the conversion to start; according to the design of the DAC, the conversion is triggered by an external signal. During the conversion process, ensure that the clock signal of the DAC is correct so that the digital signal can be converted as planned;

[0093] After the DAC completes the conversion, a stable analog signal is obtained at the output; this process is affected by the settling time of the DAC; the output analog signal is smoothed through a filter to obtain a more natural audio waveform. After passing through the DAC and the filter, the signal is converted into a continuous analog waveform, and the continuous analog waveform is the reconstructed audio signal.

[0094] DAC stands for digital-to-analog conversion.

[0095] Step A5: Detect the watermark in the reconstructed audio signal and compare the detected watermark.

[0096] In the said Step A5, extract the watermark information from the reconstructed audio signal, calculate the extracted watermark information, and obtain the watermark similarity value. The calculation method of the watermark similarity value is specifically:

[0097] , where V represents the watermark similarity value, S represents the sample points, represents the number of audio frames, represents the amplitude value of the f-th frequency point in the e-th frame of the audio;

[0098] According to the calculated watermark similarity value, if the calculated watermark similarity value is equal to the preset watermark similarity value threshold, output a security instruction and store the audio signal in the built-in memory of the Bluetooth headset; if the calculated watermark similarity value is not equal to the preset watermark similarity value threshold, output a danger instruction and go to Step A2.

[0099] It should be noted that the preset values in the present invention are determined according to specific circumstances, that is, specific numerical values are not specifically limited in this embodiment.

[0100] Finally: The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An audio recording and conversion method for a Bluetooth headset, characterized in that, Including: Step A1: Turn on the Bluetooth function of the sound source device, pair and connect via Bluetooth; and confirm the recording settings. Step A2: During the recording process, the built-in microphone of the Bluetooth headset collects audio signals in real time, and processes the collected audio signals to obtain digital signals. Step A3: Embed a watermark into the processed digital signal, and calculate the watermark evaluation value according to the embedded watermark. In the said Step A3, after embedding the watermark into the digital signal, calculate the watermark evaluation value. The specific calculation method of the first capacity value is as follows: , where D represents the first capacitance value, E represents the bandwidth of the audio carrier signal, J represents the watermarking efficiency, and K represents the attack power; The specific calculation method of the frequency-domain watermark evaluation value is as follows: I , where I represents the frequency-domain watermark evaluation value, represents the sampling frequency of the audio signal, represents the number of watermark bits embedded in each audio frequency-domain segment, represents the length of the audio time-domain segment, represents the number of audio time-domain segments, represents the number of audio frequency-domain segments; The specific calculation method of the correlation coefficient is as follows: , where X represents the correlation coefficient, t represents the bit value of the original watermark, represents the detected watermark bit value; The specific calculation method of the watermark stability value is as follows: , where is represented as the watermark stability value, X is represented as the correlation coefficient, I is represented as the frequency-domain watermark evaluation value, and D is represented as the first capacity value; The specific calculation method of the watermark sampling ratio is as follows: , where Z represents the watermark sampling ratio, represents the sampling value of the host audio signal before watermark embedding into the audio, represents the sampling value of the host audio signal after watermark embedding into the audio, and T represents the total number of samplings; The specific calculation method of the watermark evaluation value is as follows: , where Q represents the watermark evaluation value, X represents the correlation coefficient, Z represents the watermark sampling ratio, represents the watermark stability value; Compare the calculated watermark evaluation value with the preset watermark evaluation threshold. If the calculated watermark evaluation value is greater than the preset watermark evaluation threshold, output a success instruction and go to Step A5; if the calculated watermark evaluation value is less than the preset watermark evaluation threshold, output a failure instruction and re-embed the watermark. Step A4: Convert the digital signal embedded with the watermark into an analog signal and reconstruct the audio signal. Step A5: Perform watermark detection on the reconstructed audio signal and judge the detected watermark.

2. The audio recording and conversion method for a Bluetooth headset according to claim 1, wherein: In the said Step A2, amplify and denoise the collected audio signal; the specific method of denoising is as follows: Step B1 preprocesses the collected audio signal. The preprocessing includes removing the DC component and applying a window function at the front end of the signal to reduce the noise impact during processing. Step B2: Use the fast Fourier transform to convert the time-domain signal into a frequency-domain representation; after obtaining the spectrum, represent the spectrum as an amplitude spectrum and a phase spectrum. Step B3: Select a section that does not contain useful signals for noise estimation; calculate the spectrum of the noise section to obtain the amplitude spectrum of this section. Step B4: Perform spectral subtraction on the amplitude spectrum of the original signal to obtain the second amplitude spectrum. The specific calculation method of the second amplitude spectrum is as follows: , where is represented as the second amplitude spectrum obtained after removing noise, is represented as the estimated noise amplitude spectrum; is represented as the amplitude spectrum of the noise signal, is represented as a subtraction factor for further reducing the residual noise; max is used to compare two values and select the larger one; Step B5: By combining the denoised amplitude spectrum with the phase spectrum of the original signal, construct a new spectrum. The specific calculation method of the new spectrum is as follows: , where, is represented as the newly constructed spectrum, is represented as the second amplitude spectrum obtained after removing noise, is represented as the phase spectrum representing the original noisy signal, is represented as the phase angle of the a-th frequency component; Step B6: Use the inverse fast Fourier transform to convert the denoised spectrum back to the time domain to obtain the processed audio signal.

3. The audio recording and conversion method for a Bluetooth headset according to claim 2, wherein: Perform sound detection on the denoised audio, and judge whether the denoised audio has sound through the audio confirmation value. The specific calculation method of the audio confirmation value is as follows: , where R represents the audio confirmation value, represents the amplitude value of the f-th frequency point in the e-th frame, H represents the total number of audio frames, represents the length of the spectral window, represents the upper limit of the frequency point amplitude value, represents the lower limit of the frequency point amplitude value; The calculation method is specifically as follows: , where represents the amplitude value of the f-th frequency point in the e-th frame, and T represents the harmonic value. represents the spectral window length; Compare the calculated audio confirmation value with the preset audio confirmation value threshold. If the calculated audio confirmation value is greater than the preset audio confirmation value threshold, it is determined that the audio has sound; if the calculated audio confirmation value is less than the preset audio confirmation value threshold, it is determined that the audio has no sound.

4. A method for audio recording and conversion of a Bluetooth headset according to claim 1, characterized in that: In the said Step A4, select a DAC device, set the reference voltage, output range, and resolution of the DAC, and extract the conversion digital signal; write the prepared digital signal value into the data input register of the DAC and wait for the conversion to start; according to the design of the DAC, the conversion is triggered by an external signal. During the conversion process, ensure that the clock signal of the DAC is correct so that the digital signal can be converted as planned. After the DAC completes the conversion, a stable analog signal is obtained at the output; the output analog signal is smoothed by a filter to obtain a more natural audio waveform. After passing through the DAC and the filter, the signal is converted into a continuous analog waveform, and the continuous analog waveform is the reconstructed audio signal.

5. A method for audio recording and conversion of a Bluetooth headset according to claim 1, characterized in that: In step A5, watermark information is extracted from the reconstructed audio signal, and the extracted watermark information is calculated to obtain a watermark similarity value. The specific calculation method of the watermark similarity value is as follows: , where V represents the watermark similarity value, S represents the sample point, represents the number of frames of the audio, represents the amplitude value of the f-th frequency point of the e-th frame; Based on the calculated watermark similarity value, if the calculated watermark similarity value is equal to the preset watermark similarity value threshold, a safety instruction is output; if the calculated watermark similarity value is not equal to the preset watermark similarity value threshold, a danger instruction is output.

6. The audio recording and conversion method for a Bluetooth headset according to claim 5, characterized in that: When the control terminal receives the safety instruction, the audio signal is stored in the built-in memory of the Bluetooth headset; if the control terminal receives the danger instruction, it proceeds to step A2.

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