CN114067814B - Howling detection and suppression method and device based on Bluetooth audio receiver - Google Patents
Howling detection and suppression method and device based on Bluetooth audio receiver Download PDFInfo
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Abstract
The application discloses a howling detection and suppression method and a device based on a Bluetooth audio receiver, belonging to the technical field of audio decoding, wherein the method comprises the following steps: in the process of decoding the Bluetooth audio, acquiring a long-term post-filter activation flag and pitch delay corresponding to a current audio frame; judging whether the activation marks corresponding to a first preset number of previous continuous audio frames including the current audio frame are all preset values or not; if yes, judging whether the pitch delays corresponding to the first preset number of previous continuous audio frames are the same or not; and if the Bluetooth audios are the same, determining that the Bluetooth audios have howling, and starting to perform howling suppression. According to the howling detection and suppression method and device based on the Bluetooth audio receiver, whether audio howling exists is judged according to the decoding information of the long-term post-filter in the process of decoding the audio by using the audio receiver, and howling suppression is performed, so that the complexity is low, the calculation amount is small, the power consumption is low, and the method and device are suitable for being applied to low-power Bluetooth.
Description
Technical Field
The present application relates to the field of audio encoding and decoding technologies, and in particular, to a howling detection and suppression method and apparatus based on a bluetooth audio receiver.
Background
In the mainstream bluetooth audio encoder at present, the "subband coding technology (SBC)" is used most widely, and all bluetooth audio devices must support, but the tone quality is general; the advanced audio coding technology (AAC-LC) has good tone quality and wide application, is supported by a plurality of mainstream mobile phones, but has larger memory occupation and high operation complexity, a plurality of Bluetooth devices are based on an embedded platform, the battery capacity is limited, the operation capability of a processor is poorer, and the memory is limited; the high-pass Bluetooth audio coding technology (aptX series) and the Sony Bluetooth audio coding technology (LDAC) have good sound quality but high code rate, are respectively unique high-pass and Sony technologies and are closed. For the above reasons, the bluetooth international union has introduced LC3 by a number of manufacturers, which has the advantages of low delay, high sound quality and coding gain, and no special interest in the bluetooth field, and is receiving attention from a number of manufacturers.
There are many typical application scenarios for bluetooth audio, such as bluetooth-based karaoke, bluetooth-based wireless microphone/speaker, etc., which can be abstracted from the data stream as shown in fig. 1, and it can be seen that there is a feedback path (as indicated by the dashed arrow) from the speaker to the microphone, and this closed loop state makes it possible for the system to tend to be unstable when the gain is increased to a certain state, and to generate self-excited oscillation and generate howling, in order to detect and further avoid howling, in the prior art, a module can be inserted in the path of audio processing, such as before the audio encoder or after the audio decoder, to detect the generation of howling. In the existing scheme, the method based on the frequency domain is relatively accurate and widely used, but the method needs to complete time-frequency transformation, detect howling based on the characteristics obtained by the frequency domain, complete suppression, and finally convert the frequency domain signal into a time domain signal, so that the calculation amount is relatively large, the power consumption of equipment is increased, and the cruising ability of the Bluetooth equipment, especially the Bluetooth receiver equipment, is greatly influenced.
Disclosure of Invention
The method and the device for detecting and suppressing the howling based on the Bluetooth audio receiver are provided by the application, aiming at the problems that in the prior art, in the process of carrying out the howling detection and suppression, a howling detection module needs to be inserted into an audio processing path, the processing process is complex, the power consumption is high, the calculation amount is large, and the method and the device are not suitable for being applied to low-power Bluetooth.
In one aspect of the present application, a howling detection and suppression method based on a bluetooth audio receiver is provided, including: in the process of decoding the Bluetooth audio, acquiring a long-term post filter activation mark corresponding to a current audio frame; judging whether the activation marks corresponding to a first preset number of previous continuous audio frames including the current audio frame are all preset values or not; if yes, judging whether the pitch delays corresponding to the first preset number of previous continuous audio frames are the same or not; and if the Bluetooth audios are the same, determining that the Bluetooth audios have howling, and starting to perform howling suppression.
Optionally, the method further includes, during the decoding process of the bluetooth audio by the long-term post-filter, acquiring an activation flag corresponding to the current audio frame and a pitch delay corresponding to the current audio frame.
Optionally, the method further includes: calculating the current fundamental tone frequency according to the fundamental tone delay corresponding to the current audio frame; determining a current spectral coefficient index corresponding to a current audio frame according to the current fundamental tone frequency; determining an energy value corresponding to the current audio frame according to the spectral coefficient index; and if the energy value is larger than the preset threshold value, determining that the Bluetooth audio has howling.
Optionally, determining an energy value corresponding to the current audio frame according to the current spectral coefficient index includes: determining two adjacent spectral coefficient indexes with the current spectral coefficient index as the center; and calculating the energy sum of the spectral coefficients respectively corresponding to the current spectral coefficient index and the adjacent spectral coefficient index to obtain the energy value corresponding to the current audio frame.
Optionally, the start of howling suppression includes: determining a filtering parameter according to the current fundamental tone frequency, and setting a long-term post filter according to the filtering parameter; and respectively carrying out howling suppression on a second preset number of subsequent continuous audio frames including the current audio frame through a long-term post-filter.
Optionally, the starting of howling suppression further includes: and setting a notch filter according to the current fundamental tone frequency, and filtering the second preset number of subsequent continuous audio frames through the notch filter.
In one aspect of the present application, a howling detection and suppression apparatus based on a bluetooth audio receiver is provided, including: the squeal detection module detects whether squeal exists in the Bluetooth audio, and the squeal detection module comprises: the device comprises an activation mark judging module, a long-term post-filter activation mark judging module and a long-term post-filter activation mark judging module, wherein the activation mark judging module is used for acquiring the long-term post-filter activation mark corresponding to the current audio frame in the decoding process of the Bluetooth audio and judging whether the activation marks corresponding to a first preset number of previous continuous audio frames including the current audio frame are all preset values or not; the pitch delay judging module is used for judging whether the pitch delays corresponding to the first preset number of previous continuous audio frames are the same or not if the activation marks are preset numerical values, and the Bluetooth audio has howling if the activation marks are the same; and the howling suppression module is used for performing howling suppression when the Bluetooth audio has howling.
Optionally, the method further includes: and the howling confirmation module is used for reconfirming the existence of the howling of the Bluetooth audio when the howling detection module determines that the howling of the Bluetooth audio exists, and comprises the following steps: a pitch frequency confirmation module for calculating a current pitch frequency from a pitch delay corresponding to a current audio frame; the spectral coefficient index module is used for determining a current spectral coefficient index corresponding to a current audio frame according to the current fundamental tone frequency; the energy value confirmation module is used for determining a corresponding energy value corresponding to the current audio frame according to the spectral coefficient index; and the judging module judges the energy value, and determines that the Bluetooth audio has howling if the energy value is greater than a preset threshold value.
In one aspect of the present application, a computer-readable storage medium is provided, which stores computer instructions, wherein the computer instructions are operable to execute the bluetooth audio receiver based howling detection and suppression method of any one of the first aspect.
In one aspect of the present application, a computer device is provided, which includes a processor and a memory, where the memory stores computer instructions, wherein: the processor operates the computer instructions to perform the bluetooth audio receiver based howling detection and suppression method of any of the first aspect.
The beneficial effect of this application is: according to the howling detection and suppression method and device based on the Bluetooth audio receiver, whether audio howling exists is judged according to the decoding information of the long-term post-filter in the process of decoding the audio by using the audio receiver, and howling suppression is performed, so that the complexity is low, the calculation amount is small, the power consumption is low, and the method and device are suitable for being applied to low-power Bluetooth.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.
FIG. 1 is a schematic diagram of a Bluetooth audio howling generation process;
fig. 2 is an embodiment of a howling detection and suppression method based on a bluetooth audio receiver according to the present application;
fig. 3 is an example of the howling detection and suppression method based on the bluetooth audio receiver of the present application;
fig. 4 is an embodiment of a howling detection and suppression method based on a bluetooth audio receiver according to the present application;
fig. 5 is another example of the howling detection and suppression method based on the bluetooth audio receiver of the present application;
fig. 6 is an example of howling suppression in the howling detection and suppression method based on the bluetooth audio receiver according to the present application;
fig. 7 is an embodiment of the howling detection and suppression apparatus based on a bluetooth audio receiver according to the present application;
fig. 8 is an embodiment of the howling detection and suppression device based on the bluetooth audio receiver according to the present application.
With the above figures, there are shown specific embodiments of the present application, which will be described in more detail below. These drawings and written description are not intended to limit the scope of the inventive concepts in any manner, but rather to illustrate the inventive concepts to those skilled in the art by reference to specific embodiments.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims of the present application and in the above-described drawings (if any) are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises" and "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a product or apparatus that comprises a list of steps or elements is not necessarily limited to those elements explicitly listed, but may include other elements not expressly listed or inherent to such product or apparatus.
In order to detect to further avoid howling, in the prior art, a howling detection module may be inserted in the path of audio processing, for example, before the audio encoder or after the audio decoder, to detect the generation of howling and further avoid howling. The existing scheme is based on a frequency domain method for detection, is relatively accurate and wide in use, but needs to complete time-frequency transformation and detect howling based on the characteristics obtained from the frequency domain, and has the disadvantages of large calculation amount, large power consumption and extremely high calculation complexity. In the application process of the bluetooth low energy, the bluetooth low energy has a high limit on the power consumption, so the howling detection and suppression method has a great disadvantage when being applied to the bluetooth low energy.
Aiming at the problems, the voice frequency howling is detected according to the existing information of the long-term post filter in the voice frequency decoding process without specially setting an additional howling detection module, so that the howling detection process is simple and efficient, extra calculation amount is not increased, power consumption is saved, and the method is more suitable for the field of low-power Bluetooth.
Therefore, the application provides a howling detection and suppression method and device based on a Bluetooth audio receiver. The howling detection and suppression method based on the Bluetooth audio receiver comprises the following steps: in the process of decoding the Bluetooth audio, acquiring a long-term post filter activation mark corresponding to a current audio frame; judging whether the activation marks corresponding to a first preset number of previous continuous audio frames including the current audio frame are all preset values or not; if yes, judging whether the pitch delays corresponding to the first preset number of previous continuous audio frames are the same or not; and if the Bluetooth audios are the same, determining that the Bluetooth audios have howling, and starting to perform howling suppression.
The method and the device for detecting and suppressing the howling based on the Bluetooth audio receiver utilize parameters of a long-term post-filter processing process in the audio decoding process of the audio receiver, including a long-term post-filter activation flag, fundamental tone delay and the like, judge whether the howling exists in the audio according to the variation characteristics of the parameters in a multi-frame audio result process, and start to suppress the howling when the howling exists. Compared with the prior art, the method has the advantages that the corresponding howling detection and suppression process needs to be carried out through the additional howling detection module and the howling suppression module, the method is simpler and more convenient, the calculation amount is low, and the method is particularly suitable for the field of low-power-consumption Bluetooth.
The following describes the technical solutions of the present application and how to solve the above technical problems with specific embodiments. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments. Embodiments of the present application will be described below with reference to the accompanying drawings.
Fig. 2 shows an embodiment of the howling detection and suppression method based on a bluetooth audio receiver according to the present application.
In the embodiment shown in fig. 2, the howling detection and suppression method based on the bluetooth audio receiver of the present application includes: in the process of decoding the bluetooth audio, the long-term post-filter activation flag and the pitch lag corresponding to the current audio frame are obtained in the process S201.
In this embodiment, when decoding the current audio frame, in the process of decoding the current audio frame by the long-term postfilter, the long-term postfilter activation flag ltpf _ active corresponding to the current audio frame may be obtained, where the activation flag reflects whether the current audio frame contains information such as pitch. Wherein the value of the long-term post-filter activation flag is 0 or 1. If the active flag is 0, it indicates that the current audio frame does not contain the pitch, and if the active flag is 1, it indicates that the current audio frame contains the pitch.
In the embodiment shown in fig. 2, the howling detection and suppression method based on the bluetooth audio receiver of the present application includes: in the process S202, it is determined whether the activation flags corresponding to the first preset number of previous consecutive audio frames including the current audio frame are all preset values.
In this embodiment, after obtaining the long-term post-filter activation flag corresponding to the current audio frame, it is determined whether activation flags corresponding to a first preset number of previous consecutive audio frames including the current audio frame are all preset values, that is, it is determined whether activation flags corresponding to the current audio frame and a certain number of audio frames previous to the current audio frame are all preset values, where the preset value is 1, that is, it indicates that a fundamental tone exists in the audio frame. According to the characteristics of the audio, when the values of the long-term post-filter activation flags of a certain number of consecutive audio frames are all 1, it is indicated that the current audio frame has a fundamental tone frequency component with stronger energy, for example, the current audio frame includes a fundamental tone such as speech or music, or the current audio frame generates howling.
In the embodiment shown in fig. 2, the howling detection and suppression method based on the bluetooth audio receiver of the present application includes: in step S203, if yes, it is determined whether the pitch delays corresponding to the first preset number of previous consecutive audio frames are the same.
In this embodiment, when it is determined that the long-term post-filter activation flags corresponding to the first preset number of previous consecutive audio frames are all the preset value 1, the determination of the pitch lag is performed. And judging whether the pitch delays corresponding to a first preset number of previous continuous audio frames including the current audio frame are the same or not, if so, indicating that the current audio frame has a great possibility of howling.
Specifically, the voice frame is short-time and stable within 10-30 ms, so the pitch period of the voice frame is slowly changed, and if the pitch delays of the first preset number of consecutive audio frames are the same, it indicates that there is a high possibility of howling. The first preset number of the frame lengths of 10ms can be set to be 4-6; for a frame length of 7.5ms, the first preset number may be set to 5 to 7, which is a typical configuration described above, and a specific embodiment may also set other values, which may cause a false detection if the frame length is too large. The first preset number can be reasonably selected according to the actual detection requirement of the audio howling, wherein when the first preset number is set to be larger, the requirement on the detection of the audio howling is lower, and the audio howling with a smaller degree is allowed; when the first preset number is set to be smaller, the requirement for detecting the audio howling is higher, and when the audio howling occurs, the audio howling can be found in time to perform a subsequent howling suppression process. The value of the first preset number is not limited in the application.
Specifically, fig. 3 shows an example of the howling detection and suppression method based on the bluetooth audio receiver according to the present application.
As shown in fig. 3, fig. 3 is a schematic flow chart of howling detection. The method comprises the steps of firstly obtaining a long-term post-filter activation mark corresponding to a current audio frame, and then obtaining a fundamental tone delay corresponding to the current audio frame, wherein the long-term post-filter activation mark can be obtained in the process of decoding audio by the long-term post-filter. And then, starting to judge whether the activation flags of the continuous N frames are all 1, wherein the value of N is as described above, and selecting 4-6 or 5-7, wherein the activation flags are correspondingly set according to different frame lengths, if not, the process is ended, which indicates that howling does not exist in the current audio frame, if yes, the judgment of whether the pitch delays of the continuous N frames are the same is carried out, if not, the process is ended similarly, which indicates that howling does not exist in the current audio frame, if yes, the current audio frame is judged to be large and possible to have howling, and then, the suppression processing of the howling or the reconfirming process of the howling can be carried out.
Alternatively, fig. 4 shows an embodiment of the howling detection and suppression method based on the bluetooth audio receiver.
In the embodiment shown in fig. 4, the bluetooth audio receiver-based howling detection and suppression method of the present application further includes a process S401 of calculating a current pitch frequency according to a pitch delay corresponding to a current audio frame; the process S402, determining the current frequency spectrum coefficient index corresponding to the current audio frame according to the current fundamental tone frequency; the process S403, determining an energy value corresponding to the current audio frame according to the spectral coefficient index; and a process S404, if the energy value is greater than the preset threshold value, determining that the Bluetooth audio has howling.
In this alternative embodiment, it is substantially determined whether howling is present in the current audio frame by the determination of the pitch delay. However, in order to ensure the accuracy of howling detection, after the howling is determined through the pitch delay, the re-confirmation of the howling is performed, so that the false detection of the howling is avoided, and the accuracy of the howling detection is improved.
In the procedure S401 in this alternative embodiment, first, the corresponding current pitch frequency is calculated according to the pitch lag of the current audio frame, wherein when the pitch frequency is calculated, the pitch lag may be mapped to the pitch frequency according to the relationship of "sampling frequency = pitch lag × pitch frequency". For example, if the pitch lag is 32 and the working sampling rate of the long term post filter LTPF is 12.8kHz, the pitch frequency is (12800/32) =400 Hz.
In the process S402 of this alternative embodiment, after the current pitch frequency of the current audio frame is determined, the current spectral coefficient index corresponding to the current audio frame is determined according to the current pitch frequency. Specifically, if the sampling rate of the current audio is 16kHz, according to the LC3 standard, the decoder may obtain 160 spectral coefficients, and may calculate the index of the spectral coefficient corresponding to the pitch frequency of 400Hz as: (400/(16000/2)). 160= 8.
In the process S403 in this alternative embodiment, after determining the spectral coefficient index, the energy value corresponding to the current audio frame is determined according to the spectral coefficient index.
Optionally, determining an energy value corresponding to the current audio frame according to the current spectral coefficient index includes: determining two adjacent spectral coefficient indexes with the current spectral coefficient index as the center; and calculating the energy sum of the spectral coefficients respectively corresponding to the current spectral coefficient index and the adjacent spectral coefficient index to obtain the energy value corresponding to the current audio frame. And if the energy values corresponding to a preset number of continuous audio frames including the current frame continuously rise and the energy value corresponding to the current audio frame is greater than a preset threshold value, determining that the Bluetooth audio has howling.
In this alternative embodiment, due to the particularity of LD-MDCT (i.e. low-delay modified discrete cosine transform), the spectral coefficient with local maximum energy does not completely correspond to the relevant real frequency point, and usually has a deviation of-1 to +1, for example, 400Hz obtained in LTPF, the corresponding spectral coefficient with maximum energy is not necessarily the spectral coefficient with index of 8, and may also be 7 or 9; therefore, when calculating the energy, the energy sum of 3 spectral coefficients centered on the spectral coefficient index is calculated, and the corresponding spectral coefficient index is denoted as n, then the energy of the frequency point is:
wherein, the
And representing the spectral coefficient corresponding to the spectral coefficient index k of the current audio frame. After the spectral coefficient of the current audio frame is determined, the energy values corresponding to the successive audio frames need to be compared subsequently. Wherein, assuming that the energy of the consecutive N frames is recorded as E1, E2, …, En when the energy continuously rises to the finger>,…,>E1>E0。
Specifically, since the speech signal is a short-time stationary signal, which is generally stationary within 10ms to 30ms, the time corresponding to the frames here should be greater than 30ms, and the frame length is 10ms, for example, at least 4 frames, corresponding to 40 ms. For the setting of the preset number, appropriate setting may be performed according to the frame lengths of different audio frames, and the present application is not particularly limited.
In the process S404 in this optional embodiment, the calculated energy value and the preset threshold are determined, and if the energy value is greater than the preset threshold, it is determined that there is a howling in the bluetooth audio.
Specifically, in order to prevent erroneous judgment, when the threshold is set, the threshold may be set according to a typical howling scene test, if the threshold is too small, the howling may be frequently detected and suppressed, so that the sound quality is reduced, and if the threshold is too large, the howling may be already in the later stage of the howling, so that the volume is saturated, so that more harmonics are introduced into a single-frequency signal, and the requirements on the stability of detection and suppression are improved.
Fig. 5 shows another example of the howling detection and suppression method based on the bluetooth audio receiver according to the present application.
As shown in fig. 5, fig. 5 is a schematic flow chart of howling confirmation. Firstly, the fundamental tone frequency, namely the howling frequency, is calculated according to the fundamental tone delay of the current audio frame, and then the fundamental tone frequency is mapped into the spectral coefficient index to obtain the corresponding spectral coefficient index. And then calculating a corresponding energy value according to the spectral coefficient index, wherein the energy value is the sum of energy values corresponding to three vertically floating spectral indexes because the spectral coefficient is changed vertically, judging whether the energy value corresponding to the current audio frame exceeds a preset threshold value by judging whether the energy values of continuous multiple frames continuously rise or not, and if so, confirming that howling is detected and starting howling suppression.
In the embodiment shown in fig. 2, the howling detection and suppression method based on the bluetooth audio receiver of the present application includes: in the process S204, if the bluetooth audio is the same, it is determined that howling exists in the bluetooth audio, and howling suppression is started.
Optionally, the start of howling suppression includes: determining a filtering parameter according to the current fundamental tone frequency, and setting a long-term post filter according to the filtering parameter; and respectively carrying out howling suppression on a second preset number of subsequent continuous audio frames including the current audio frame through a long-term post-filter.
In this alternative embodiment, when performing howling suppression, first, a current pitch frequency corresponding to a current audio frame is determined according to a pitch delay of the current audio frame. And setting parameters of the notch filter according to the fundamental tone frequency, wherein designing parameters of the notch filter according to the fundamental tone frequency, that is, the notch frequency is a relatively mature technology, and the invention is not limited. And after the filtering parameters of the notch filter are obtained, setting the long-term post filter by using the filtering parameters, so that howling suppression is respectively carried out on a second preset number of post-continuous audio frames including the current audio frame by the reset long-term post filter.
Specifically, fig. 6 shows an example of howling suppression in the howling detection and suppression method based on the bluetooth audio receiver according to the present application.
As shown in fig. 6, when performing howling suppression, it is first determined whether the number P of audio frames subjected to howling suppression is greater than zero, where P is a second preset number. If yes, subtracting 1 from P, and calculating to obtain corresponding pitch frequency according to the pitch delay of the current audio frame. And setting the corresponding filtering parameters of the notch filter according to the fundamental tone frequency, replacing the parameters in the long-term post filter through the filtering parameters, finishing the setting of the long-term post filter, starting filtering, filtering the clutter, reducing the influence of howling and improving the tone quality. The pitch frequency enhancement is mainly accomplished in the standard LC3 by the filtering module in the long term post filter LTPF, which mainly plays a role in the present invention: when no howling occurs: completing the reinforcement of the fundamental tone frequency according to a normal filtering process; when there is a howling: and trapping the howling frequency to finish the suppression of the howling frequency.
Specifically, in order to effectively suppress howling, it is usually necessary to suppress the howling continuously for a certain period of time, such as 100-200 ms, and the number of frames is related to the specific codec and the selected frame length, for example, if the LC3 is configured with a 10ms frame length, P may be set to 10-20.
Optionally, a notch filter is set according to the current pitch frequency, and the second preset number of subsequent consecutive audio frames are filtered by the notch filter.
In the optional embodiment, the howling suppression process is performed on the second preset number of subsequent consecutive audio frames including the current audio frame, and a corresponding notch filter may be further set according to the current fundamental tone frequency corresponding to the current audio frame, so as to filter the clutter in the audio frames, thereby suppressing the audio howling and improving the audio quality.
Specifically, designing a notch filter according to a known pitch frequency is a mature technology, and the application is not limited. Wherein, the notch filter can select a Finite Impulse Response (FIR) filter or an Infinite Impulse Response (IIR) filter.
According to the howling detection and suppression method based on the Bluetooth audio receiver, the existing parameters of the Bluetooth audio processing by the long-term post filter are utilized in the audio decoding process, the long-term post filter activation mark and the fundamental tone delay of the current audio frame are obtained, and the audio howling is detected. The pitch lag and the like mentioned in the above process are intermediate processing data in the long-term post-filter processing process, so that the detection of the audio howling can be performed without extra operation. Therefore, the complexity of the audio howling detection process is reduced, the calculation amount is reduced, and the power consumption is reduced. In addition, the fundamental tone frequency is determined through the fundamental tone delay, the energy value corresponding to the current audio frame is determined, and the howling detection result is reconfirmed through the judgment of the energy value, so that the accuracy of the howling detection is improved. The method can be applied to the Bluetooth low energy, and can also be applied to the classic Bluetooth by matching with the LC3 Bluetooth low energy. The method and the device make full use of the existing information of the audio encoder, assist a small amount of calculation, have low complexity, and save time-frequency conversion which consumes resources greatly compared with the traditional frequency domain howling removing algorithm. Because time-frequency transformation does not exist, a large amount of computation required by the traditional time-frequency transformation is saved, and the method is easy to deploy in embedded equipment. Compare with prior art, be applicable to the bluetooth low energy field more.
Fig. 7 shows an embodiment of the howling detection and suppression device based on a bluetooth audio receiver according to the present application.
In the embodiment shown in fig. 7, the howling detection and suppression device based on a bluetooth audio receiver of the present application includes: a howling detection module 701, configured to detect whether a howling exists in the bluetooth audio, where the howling detection module includes: the device comprises an activation mark judging module, a long-term post-filter activation mark judging module and a long-term post-filter activation mark judging module, wherein the activation mark judging module is used for acquiring the long-term post-filter activation mark corresponding to the current audio frame in the decoding process of the Bluetooth audio and judging whether the activation marks corresponding to a first preset number of previous continuous audio frames including the current audio frame are all preset values or not; the pitch delay judging module is used for judging whether the pitch delays corresponding to the first preset number of previous continuous audio frames are the same or not if the activation marks are preset numerical values, and the Bluetooth audio has howling if the activation marks are the same; and a howling suppression module 702, configured to perform howling suppression when there is howling in the bluetooth audio.
Alternatively, fig. 8 shows an embodiment of the howling detection and suppression device based on a bluetooth audio receiver according to the present application.
In the embodiment shown in fig. 8, the apparatus for detecting and suppressing howling based on a bluetooth audio receiver further includes: the howling confirmation module 703, when the howling detection module determines that the howling exists in the bluetooth audio, reconfirms that the howling exists in the bluetooth audio, includes: a pitch frequency confirmation module for calculating a current pitch frequency from a pitch delay corresponding to a current audio frame; the spectral coefficient index module is used for determining a current spectral coefficient index corresponding to a current audio frame according to the current fundamental tone frequency; the energy value confirmation module determines the energy value corresponding to the current audio frame according to the spectral coefficient index; and the judging module judges the energy value, and determines that the Bluetooth audio has howling if the energy value is greater than a preset threshold value.
Optionally, in the howling suppression module, the current pitch frequency is determined according to the pitch delay corresponding to the current audio frame; determining a filtering parameter according to the current fundamental tone frequency, and setting a long-term post filter according to the filtering parameter; and respectively carrying out howling suppression on a second preset number of subsequent continuous audio frames including the current audio frame through a long-term post-filter.
Optionally, in the howling suppression module, a notch filter is set according to the current pitch frequency, and the second preset number of subsequent consecutive audio frames are filtered by the notch filter.
According to the howling detection and suppression device based on the Bluetooth audio receiver, the existing parameters of the Bluetooth audio processing by the long-term post filter are utilized in the audio decoding process, the long-term post filter activation mark and the fundamental tone delay of the current audio frame are obtained, and the audio howling is detected. The pitch lag and the like mentioned in the above process are intermediate processing data in the long-term post-filter processing process, so that the detection of the audio howling can be performed without extra operation. Therefore, the complexity of the audio howling detection process is reduced, the calculation amount is reduced, and the power consumption is reduced. In addition, the fundamental tone frequency is determined through the fundamental tone delay, the energy value corresponding to the current audio frame is determined, and the howling detection result is reconfirmed through the judgment of the energy value, so that the accuracy of the howling detection is improved. The method can be applied to the Bluetooth low energy, and can also be applied to the classic Bluetooth by matching with the LC3 Bluetooth low energy. The method and the device make full use of the existing information of the audio encoder, assist a small amount of calculation, have low complexity, and save time-frequency conversion which consumes resources greatly compared with the traditional frequency domain howling removing algorithm. Because time-frequency transformation does not exist, a large amount of computation required by the traditional time-frequency transformation is saved, and the method is easy to deploy in embedded equipment. Compare with prior art, be applicable to the bluetooth low energy field more.
In a particular embodiment of the present application, a computer-readable storage medium stores computer instructions, wherein the computer instructions are operable to perform the howling detection and suppression method based on a bluetooth audio receiver described in any one of the embodiments. Wherein the storage medium 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 one embodiment of the present application, a computer device includes a processor and a memory, the memory storing computer instructions, wherein: the processor operates the computer instructions to perform the howling detection and suppression method based on a bluetooth audio receiver described in any of the embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed apparatus may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, a division of a unit is merely a logical division, and an actual implementation may have another division, 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.
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 embodiments are merely examples, which are not intended to limit the scope of the present disclosure, and all equivalent structural changes made by using the contents of the specification and the drawings, or any other related technical fields, are also included in the scope of the present disclosure.
Claims (7)
1. A howling detection and suppression method based on a Bluetooth audio receiver is characterized by comprising the following steps:
in the process of decoding the Bluetooth audio, acquiring a long-term post-filter activation flag and pitch delay corresponding to a current audio frame;
judging whether the activation marks corresponding to a first preset number of previous continuous audio frames including the current audio frame are all preset values or not;
if yes, judging whether the pitch delays corresponding to a first preset number of the previous continuous audio frames are the same or not;
if the current audio frame is the same as the current audio frame, calculating the current pitch frequency according to the pitch delay corresponding to the current audio frame;
determining a current spectral coefficient index corresponding to the current audio frame according to the current fundamental tone frequency;
determining two adjacent spectral coefficient indexes centered on the current spectral coefficient index;
calculating the energy sum of the spectral coefficients respectively corresponding to the current spectral coefficient index and the adjacent spectral coefficient index to obtain an energy value corresponding to the current audio frame;
and if the energy values corresponding to a preset number of continuous audio frames including the current audio frame continuously rise and the energy value corresponding to the current audio frame is greater than a preset threshold value, determining that howling exists in the Bluetooth audio, and starting howling suppression, wherein the first preset number is an integer at least greater than or equal to 2.
2. The method of claim 1, further comprising:
and in the process of decoding the Bluetooth audio by a long-term post-filter, acquiring the activation flag corresponding to the current audio frame and the pitch delay corresponding to the current audio frame.
3. The method of claim 1, wherein the initiating howling suppression comprises:
determining a filtering parameter according to the current fundamental tone frequency, and setting a long-term post filter according to the filtering parameter;
and respectively carrying out howling suppression on a second preset number of rear continuous audio frames including the current audio frame through the set long-term post-filter.
4. A method of howling detection and suppression based on a bluetooth audio receiver according to claim 3, wherein said initiating howling suppression further comprises:
and setting a notch filter according to the current fundamental tone frequency, and filtering the second preset number of subsequent continuous audio frames through the notch filter to perform howling suppression.
5. A howling detection and suppression apparatus based on a bluetooth audio receiver, comprising:
the howling detection module detects whether howling exists in the Bluetooth audio, and comprises:
the device comprises an activation sign judgment module, a long-term post-filter activation sign and gene delay, wherein the activation sign judgment module is used for acquiring a long-term post-filter activation sign and gene delay corresponding to a current audio frame in the process of decoding the Bluetooth audio, and judging whether the activation signs corresponding to a first preset number of previous continuous audio frames including the current audio frame are all preset values or not;
a pitch delay judging module, configured to judge whether pitch delays corresponding to a first preset number of previous consecutive audio frames are the same if the active flags are preset values, and if so, determine that the bluetooth audio has howling;
a howling confirmation module, configured to reconfirm the presence of howling of the bluetooth audio when the howling detection module determines that the howling of the bluetooth audio exists, including
A pitch frequency determination module for calculating a current pitch frequency from the pitch delay corresponding to the current audio frame;
a spectral coefficient index module, which determines a current spectral coefficient index corresponding to the current audio frame according to the current fundamental tone frequency, and determines two adjacent spectral coefficient indexes with the current spectral coefficient index as a center;
the energy value confirmation module is used for calculating the energy sum of the spectral coefficients respectively corresponding to the current spectral coefficient index and the adjacent spectral coefficient index to obtain the energy value corresponding to the current audio frame;
and the howling suppression module is used for judging the energy value, if the energy values corresponding to a preset number of continuous audio frames including the current audio frame continuously rise and the energy value corresponding to the current audio frame is greater than a preset threshold value, determining that howling exists in the Bluetooth audio, and starting to perform howling suppression, wherein the first preset number is an integer at least greater than or equal to 2.
6. A computer readable storage medium storing computer instructions, wherein the computer instructions are operative to perform the bluetooth audio receiver based howling detection and suppression method of any one of claims 1-4.
7. A computer device comprising a processor and a memory, the memory storing computer instructions, wherein: the processor operates the computer instructions to perform the bluetooth audio receiver based howling detection and suppression method of any one of claims 1-4.
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