CN114420148B - Howling detection and suppression method, device, medium and equipment - Google Patents
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Abstract
The application discloses a howling detection and suppression method, a device, a medium and equipment, belonging to the technical field of audio coding, wherein the method comprises the following steps: performing sub-band decomposition on an input current audio frame through an SBC encoder or a decoder to obtain a plurality of sub-bands, and numbering the sub-bands in sequence; calculating the energy of each sub-band to obtain the energy of the sub-band; sequentially determining the first continuous rising times of the sub-band energy of each current sub-band in the current audio frame relative to the sub-band energy of the historical sub-band with the same sub-band number in the historical audio frame; and under the condition that the first time number is larger than a first preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting to perform howling suppression. According to the method and the device, the energy of the sub-band of the obtained audio signal is detected by utilizing the inherent coding and decoding process of the SBC coder-decoder, and the howling is judged and inhibited. Unnecessary processing procedures are reduced, power consumption for howling detection and inhibition on the SBC audio codec is reduced, and computing power is saved.
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, apparatus, medium, and device.
Background
As a mandatory requirement of the A2DP protocol, the audio codec which is most widely used and must be supported by all the classic bluetooth audio devices, SBC, is of no doubt importance and wide application; in a typical SBC-based bluetooth application scenario, such as bluetooth-based karaoke, bluetooth-based wireless microphone/speaker, etc., it can be abstracted from the data flow perspective as shown in fig. 1, where there is a feedback path from the speaker to the microphone (as shown by the dashed line with an arrow), and this closed loop state makes it possible that when the system loop tends to be unstable when the gain increases to a certain state, howling occurs due to self-oscillation.
In order to avoid howling in the bluetooth audio system, in the prior art, a howling avoiding module may be inserted in the path of audio processing, for example, before the audio encoder or after the audio decoder, so as to avoid the occurrence of howling. In the prior art, the module can be processed based on a subband technology and mainly comprises the following three steps: firstly, dividing an audio signal into a plurality of sub-bands through a sub-band analyzer; then, carrying out howling detection and inhibition on the sub-band; and finally, synthesizing the signals after the howling suppression by a sub-band synthesizer to obtain audio signals. The processing module can effectively complete the detection and inhibition of howling, and has the defects that the subband decomposition and synthesis are required to be completed, the calculation amount is large, the power consumption of a system is increased, the service time of equipment is shortened, and the user experience is reduced; based on the characteristics of subband decomposition and synthesis, a certain time delay needs to be introduced, and the user experience is also reduced.
Disclosure of Invention
The present application provides a howling detection and suppression method, device, medium, and apparatus, aiming at the problems that in the prior art, in an SBC codec, the existing howling detection and suppression method is large in computation amount and high in power consumption.
In one aspect of the present application, a howling detection and suppression method is provided, including: performing sub-band decomposition on an input current audio frame through an SBC encoder or decoder to obtain a plurality of sub-bands, and numbering the sub-bands in sequence; calculating the energy of each sub-band to obtain sub-band energy; comparing the sub-band energy corresponding to the sub-band with the same number of sub-bands from the current audio frame and the plurality of historical audio frames, wherein the first time of continuous rising of the sub-band energy of each current sub-band in the current audio frame relative to the sub-band energy of the historical sub-band with the same number of sub-bands in the historical audio frames is determined in sequence; and under the condition that the first time number is larger than a first preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting to perform howling suppression.
Optionally, the SBC encoder performs subband decomposition on the input current audio frame to obtain multiple subbands, including: in the encoding process of the SBC encoder for the current audio frame, the current audio frame is decomposed through an analysis filter bank in the SBC encoder to obtain a plurality of sub-bands.
Optionally, determining a first rising time of the subband energy of the current subband in the current audio frame relative to the subband energy of the historical subband with the same subband number in the historical audio frame includes: and judging whether the sub-band energy of the current sub-band is greater than the sub-band energy of the historical sub-band with the same sub-band number in the previous historical audio frame, if so, adding one to the first time, and otherwise, resetting the first time.
Optionally, under the condition that the first number is greater than a first preset threshold, determining that howling exists in the current audio frame at the current subband, and starting howling suppression, the method further includes: judging whether the sub-band energy of the current sub-band is greater than a preset energy threshold value or not under the condition that the first time number is greater than a first preset threshold value; and if so, determining that howling exists at the current sub-band.
Optionally, under the condition that the first number is greater than a first preset threshold, determining that howling exists in the current audio frame at the current subband, and starting howling suppression, the method further includes: under the condition that the first time number is not larger than a first preset threshold value, sequentially calculating the energy ratio of the sub-band energy of the current sub-band to the sub-band energy sum of each sub-band in the current audio frame; determining a second time that the energy ratio of the current sub-band in the current audio frame is continuously larger than or equal to a preset ratio relative to the energy ratio of a historical sub-band with the same sub-band number in the historical audio frame; and under the condition that the second number is greater than a second preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting to carry out howling suppression.
Optionally, determining that howling exists in the current sub-band in the current audio frame, and starting howling suppression, includes: and carrying out phase transformation and gain reduction processing on the sub-band with the howling in the current audio frame through an all-pass filter.
In one aspect of the present application, a howling detection and suppression apparatus is provided, including: the analysis filter bank carries out sub-band decomposition on the current audio frame input by the SBC encoder to obtain a plurality of sub-bands, and the sub-bands are numbered in sequence; the system comprises a howling detection module, a howling detection module and a howling detection module, wherein the howling detection module is used for calculating the energy of each sub-band to obtain sub-band energy, comparing the sub-band energy corresponding to the sub-band with the same number when the same sub-band goes to the numbered sub-band in a current audio frame and a plurality of historical audio frames, determining the first time number of continuous rise of the sub-band energy of the current sub-band relative to the sub-band energy of the historical sub-band with the same number when the current audio frame is in the historical audio frame, and determining that the howling exists in the current sub-band in the current audio frame under the condition that the first time number is greater than a first preset threshold value; and a howling suppression module which performs howling suppression on the sub-band in which howling exists.
In one aspect of the present application, a computer-readable storage medium is provided that stores computer instructions, wherein the computer instructions are operable to perform the howling detection and suppression method of aspect one.
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, and the processor operates the computer instructions to execute the howling detection and suppression method in the first aspect.
The beneficial effect of this application is: according to the method and the device, the energy of the sub-band of the obtained audio signal is detected by utilizing the inherent coding and decoding process of the SBC coder-decoder, and the howling is judged and inhibited. Unnecessary processing procedures are reduced, power consumption for howling detection and inhibition on the SBC audio codec is reduced, and computing power is saved.
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 a flow chart of an embodiment of the howling detection and suppression method of the present application;
FIG. 3 is a response diagram of an all-pass filter with gain and phase adjustment;
fig. 4 is a schematic diagram of an example of the howling detection and suppression method of the present application;
fig. 5 is a schematic structural diagram of an embodiment of the howling detection and suppression device 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.
As a mandatory requirement of the A2DP protocol, the audio codec which is most widely used and must be supported by all the classic bluetooth audio devices, SBC, is of no doubt importance and wide application; in a typical SBC-based bluetooth application scenario, such as bluetooth-based karaoke, bluetooth-based wireless microphone/speaker, etc., it can be abstracted from the data flow perspective as shown in fig. 1, where there is a feedback path from the speaker to the microphone (as shown by the dashed line with an arrow), and this closed loop state makes it possible that when the system loop tends to be unstable when the gain increases to a certain state, howling occurs due to self-oscillation.
In order to avoid howling in the bluetooth audio system, a howling-avoiding module may be inserted in the audio processing path in the prior art, for example, before the audio encoder or after the audio decoder, so as to avoid the howling. In the prior art, the module can be processed based on a subband technology and mainly comprises the following three steps: firstly, dividing an audio signal into a plurality of sub-bands through a sub-band analyzer; then, carrying out howling detection and inhibition on the sub-band; and finally, synthesizing the signals after the howling suppression by a sub-band synthesizer to obtain audio signals. The processing module can effectively complete the detection and inhibition of howling, and has the defects that the subband decomposition and synthesis are required to be completed, the calculation amount is large, the power consumption of a system is increased, the service time of equipment is shortened, and the user experience is reduced; based on the characteristics of subband decomposition and synthesis, a certain time delay needs to be introduced, and the user experience is also reduced. According to the encoding and decoding principle of the SBC audio encoder and decoder, the SBC audio encoder has a sub-band dividing function, so that if the existing howling detection and suppression method is applied to the SBC encoder, the processing process is repeated, and the power consumption is increased. Therefore, in the SBC encoder, the subband division function of the SBC encoder is utilized to assist in detecting and determining subband energy, so as to detect audio howling, thereby reducing power consumption and saving computational effort in the howling detection process.
In order to solve the above problems, the present application provides a howling detection and suppression method, apparatus, medium, and device, where the method includes: performing sub-band decomposition on an input current audio frame through an SBC encoder or a decoder to obtain a plurality of sub-bands, and numbering the sub-bands in sequence; calculating the energy of each sub-band to obtain the energy of the sub-band; comparing the sub-band energy corresponding to the sub-band with the same number of sub-bands from the current audio frame and the plurality of historical audio frames, wherein the first time of continuous rising of the sub-band energy of each current sub-band in the current audio frame relative to the sub-band energy of the historical sub-band with the same number of sub-bands in the historical audio frames is determined in sequence; and under the condition that the first time number is larger than a first preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting to perform howling suppression.
The howling detection and suppression method is mainly used for an SBC encoder, each sub-band of an input audio signal is directly obtained by utilizing the existing sub-band division process in the encoding process, and whether audio howling exists in each sub-band is judged by detecting and analyzing the energy of each sub-band. Compared with the existing howling detection method, the method omits the sub-band division step with higher power consumption, thereby reducing the power consumption and being more suitable for the howling detection process of the SBC encoder.
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 of the present application.
In the embodiment shown in fig. 1, the howling detection and suppression method of the present application includes a process S201, performing sub-band decomposition on an input current audio frame through an SBC encoder or decoder to obtain a plurality of sub-bands, and numbering the sub-bands in sequence.
In this embodiment, the howling detection and suppression method of the present application directly uses the sub-band division process of the SBC encoder during audio encoding to perform sub-band division of the audio signal, without an additional sub-band division process, thereby reducing power consumption caused by sub-band division and saving computational effort. After the input current audio frame is divided into sub-bands, the sub-bands are numbered according to the sub-band sequence.
Specifically, for a frame of audio, after the sub-bands are divided, the number of sub-bands may be 4 or 8. For example, for the example of an mSBC encoder, for a sampling rate of 16kHz, with a maximum bandwidth of 8kHz, if divided into 8 subbands, the subband frequency range is: subband 0: 0 kHz-1 kHz; subband 1: 1 kHz-2 kHz sub-band 2: 2 kHz-3 kHz; sub-band 3: 3 kHz-4 kHz sub-band 4: 4 kHz-5 kHz; sub-band 5: 5 kHz-6 kHz sub-band 6: 6 kHz-7 kHz; sub-band 7: 7 kHz-8 kHz. Where the numbers 0-7 are the subband numbers for these 8 subbands.
Optionally, the SBC encoder performs subband decomposition on the input current audio frame to obtain multiple subbands, including: in the encoding process of the SBC encoder for the current audio frame, the current audio frame is decomposed through an analysis filter bank in the SBC encoder to obtain a plurality of sub-bands.
In this alternative embodiment, during the encoding process of the SBC encoder, the audio signal is decomposed by the analysis filter bank in the SBC encoder to obtain each sub-band. Where the analysis filter bank is an existing module in the SBC encoder, typically at a bluetooth transmitter, such as a microphone with a bluetooth transmitter.
In the embodiment shown in fig. 2, the howling detection and suppression method of the present application includes a process S202, which calculates the energy of each sub-band to obtain the sub-band energy.
In this embodiment, after obtaining each subband of the current audio frame, the energy of each subband is calculated. For subsequent detection of audio howling by subband energy.
In the embodiment shown in fig. 2, the howling detection and suppression method of the present application includes a process S203 of comparing subband energies corresponding to subbands where the same subband goes to the number in a current audio frame and multiple historical audio frames, and sequentially determining a first number of times that the subband energy of each current subband in the current audio frame continuously rises relative to the subband energy of a historical subband with the same subband number in the historical audio frame.
In this embodiment, after the energy of each subband in the current audio frame is calculated, the energy of the subbands with the same subband number in the current audio frame and the energy of the subbands with the same subband number in the historical audio frame are compared, and the first number of times that the subband energy continuously rises is determined.
Optionally, determining a first rising time of the subband energy of the current subband in the current audio frame relative to the subband energy of the historical subband with the same subband number in the historical audio frame includes: and judging whether the sub-band energy of the current sub-band is greater than the sub-band energy of the historical sub-band with the same sub-band number in the previous historical audio frame, if so, adding one to the first time, and otherwise, resetting the first time.
In this optional embodiment, when counting the first number of times that the subband energy continuously rises, the relationship between the subband energy of the current subband in the current audio frame and the subband energy of the historical subband having the same subband number in the previous audio frame is determined, if the relationship is greater than the relationship, the first number of times that the subband energy continuously rises is increased by one, otherwise, the first number of times is cleared.
Specifically, for example, after sub-band division is performed in the current audio frame, the sub-band energy of number 0 is 4; in the last audio frame, the subband energy numbered 0 is 3; then, in the previous audio frame, the energy of the sub-band with the number 0 is 2; the energy of the sub-band of the previous audio frame number 0 is 1; the subband energy of number 0 in the next previous audio frame is 2. Therefore, in the five audio frames, since the subband energy 4>3>2>1<2, the first number of continuous rises in the current audio frame is 3.
In the embodiment shown in fig. 2, the howling detection and suppression method of the present application includes a process S204, where under the condition that the first time number is greater than a first preset threshold, it is determined that a howling exists at a current subband in a current audio frame, and howling suppression is started.
In this embodiment, after determining the first number of times that the energy of the sub-band continues to rise, by determining the relationship between the first number of times and a first preset threshold, when the first number of times is greater than the first preset threshold, it is determined that howling exists at the current sub-band, and at this time, howling suppression is started. After the howling of the audio is detected, the howling suppression is performed on the generated sub-band instead of the whole audio frame, so that the efficiency of the howling suppression is improved.
Specifically, in the above example, it is determined that the first number of times that the subband energy of the subband No. 0 in the current audio frame continues to rise is 3, and if the first preset threshold value is 2, it indicates that there is howling in the subband No. 0 at this time, and the howling suppression is subsequently performed on the subband No. 0. In addition, taking the example of dividing a frame of audio frame into four sub-bands, after determining whether howling exists in the sub-band numbered 0, it is then determined whether howling exists in the sub-band numbered 1, the sub-band numbered 2, and the sub-band numbered 3, and the determining method is similar to that of the sub-band numbered 0, and is not described herein again.
Specifically, in the SBC encoder, 4 or 8 subbands are output after an input frame of audio signal passes through an analysis filter, and when analyzing whether there is howling in the subbands, the multiple subbands are sequentially determined. Correspondingly, the subband numbers may be set to 0-3 or 0-7. The first preset threshold is a threshold for judging whether to perform howling, and is an empirical value, and may be selected according to the size of a speech frame in practice, where a speech signal is usually a short-time stationary signal, energy on a certain sub-band fluctuates up and down, and if the energy of a certain sub-band continuously increases, howling is likely to occur at a frequency on the current sub-band. In a typical scenario, howling usually occurs within 1-2 seconds from generation to saturation, and the howling must be quickly detected and suppressed, a value of a typical first preset threshold may correspond to a time duration of 50-100 ms, for example, in an SBC, a frame time duration is about 2.7ms, and then M corresponds to 18-36 frames. Any value of 18 to 36 may be selected as the first preset threshold, it should be noted that the selection of the first preset threshold may be reasonably selected according to the conditions of the requirement of howling detection, and the like, and the application is not particularly limited. For example, when the first preset threshold is set to 20, and at this time, when howling is detected, the input current audio frame is at least 22 th frame of audio, and at this time, the first frequency which may be the largest is 21, and at this time, it may be determined whether howling exists.
Optionally, under the condition that the first number is greater than a first preset threshold, determining that howling exists in the current audio frame at the current subband, and starting howling suppression, the method further includes: judging whether the sub-band energy of the current sub-band is greater than a preset energy threshold value or not under the condition that the first time number is greater than a first preset threshold value; and if so, determining that howling exists at the current sub-band.
In this optional embodiment, in order to improve the accuracy of howling detection, when it is determined that the first number corresponding to the current sub-band is greater than a first preset threshold, the sub-band energy of the current sub-band and a preset energy threshold are determined, and if the sub-band energy of the current sub-band is greater than the preset energy threshold, it is determined that audio howling exists in the current sub-band, and howling suppression is performed on the current sub-band.
Optionally, under the condition that the first number is greater than a first preset threshold, determining that howling exists in the current audio frame at the current subband, and starting howling suppression, the method further includes: under the condition that the first time is not more than a first preset threshold value, sequentially calculating the energy ratio of the sub-band energy of the current sub-band to the sub-band energy sum of each sub-band in the current audio frame; determining the second number of continuous rising of the energy ratio of the current sub-band in the current audio frame relative to the energy ratio of the historical sub-band with the same sub-band number in the historical audio frame; and under the condition that the second number of times is larger than a second preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting to perform howling suppression.
In this optional embodiment, in the detection process of howling, the number of times of continuous rise of the sub-band energy is determined, and similarly, the determination may be performed according to the proportion of the sub-band energy to the total energy of the sub-band. In order to ensure the accuracy and comprehensiveness of judgment, the energy ratio of the sub-band energy of the current sub-band to the sub-band energy sum of each sub-band in the current audio frame is calculated in sequence; and determining the second time of the continuous rise of the energy ratio of the current sub-band relative to the energy ratio of the historical sub-band with the same sub-band number in the historical audio frame, and judging whether to carry out howling or not by comparing the second time with a second preset threshold value.
Specifically, the second number of continuous occurrences of the ratio of the sub-band energy to the total energy of the sub-band is greater than a specified second preset threshold, which indicates that the main energy is concentrated in a certain sub-band, and also indicates that there may be howling in the current sub-band. The value of the second frequency is similar to the definition of the first frequency, in a typical scene, the preset ratio of the energy of the howling sub-band to the total energy of the sub-band can reach 0.6-0.7, depending on a specific application scene and the bandwidth of the sub-band, and the ratio threshold can be determined by referring to measured data. The value of the preset ratio can be selected from a range of 0.6 to 0.7, the second preset threshold can be selected from a range of 18 to 36, and it should be noted that, regarding the range and the value of the specific value, the above shows a preferred choice, and the protection scope of the present application is not specifically limited. In the later period of howling, when the howling signal overflows, a single-frequency signal of the howling can generate a plurality of harmonics, and detection omission can be effectively prevented according to the energy ratio.
Specifically, for example, after sub-band division is performed in the current audio frame, the ratio of the sub-band energy with the number 0 to the total energy is 0.8; in the last audio frame, the ratio of the sub-band energy with the number of 0 to the total energy is 0.75; in the last audio frame, the ratio of the sub-band energy with the number of 0 to the total energy is 0.7; the ratio of the sub-band energy of the previous audio frame number 0 to the total energy is 0.65; the ratio of the energy of the sub-band with the number 0 in the previous audio frame to the total energy is 0.7. When the preset ratio is 0.6, it is known that 0.65>0.6, 0.7>0.6, 0.75>0.6, and 0.8>0.6, and thus the second number of times that the subband numbered 0 continues to be greater than or equal to the preset suppression in the current audio frame is 4. If the second preset threshold is set to 2, in the current audio frame, since 4>2, howling exists in the subband numbered 0, and howling suppression is performed on the subband. For another example, taking subband 0 as an example, if the energy ratios of consecutive 18 frames are: 0.1,0.1,0.1,0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.6,0.7,0.7,0.7,0.7,0.7,0.7,0.7. And if the last 10 frames are all larger than or equal to the preset ratio of 0.6, determining that the second time is 10. The judgment process of the sub-band with other number is similar to the judgment process of the sub-band with number 0, and is not described herein again.
Optionally, determining that howling exists in the current sub-band in the current audio frame, and starting to perform howling suppression, includes: and carrying out phase transformation and gain reduction processing on the sub-band with howling in the current audio frame through an all-pass filter.
In the optional embodiment, for the howling generation sub-band in which the howling is detected, the howling suppression is performed by using a method of combining gain reduction and phase change.
Specifically, the gain of a sub-band with howling is reduced to 3 dB-6 dB generally; the phase of the sub-band signal which generates the howling is changed by using an all-pass filter to suppress the howling; the use of an all-pass filter to change the phase of a signal is a relatively mature technique and the invention is not limited; the human ear hearing is insensitive to the phase and is not easy to be perceived after the phase is modified; the formula of the all-pass filter combining gain reduction and phase change is as follows
Wherein
， 
Is the frequency of the cut-off to frequency,
is the sampling frequency, Rnd is a random number within the range of 0.0-1.0, and is randomly generated before the filtering of the howling subband of each frame, so as to ensure that the phase of the all-pass filter is randomly changed.
In particular, fig. 3 shows a response diagram of an all-pass filter with gain and phase adjustment.
As shown in fig. 3, the magnitude response is shown as a horizontal line, the magnitude response being the same for all spectral components, here about-6 dB, i.e. the same attenuation for all spectral components;
the phase response is shown by the upper left to lower right curve, and has different phase responses to different frequency spectrum components;
by simultaneously changing the amplitude and the phase of the howling sub-band, two conditions which must be met by the howling are destroyed, and the fast howling suppression is ensured.
Specifically, fig. 4 shows an example of the howling detection and suppression method of the present application.
The howling detection and suppression method of the present application is further described below with reference to fig. 4. In the encoding process of the SBC encoder, an input current audio frame is decomposed through an analysis filter bank to obtain each sub-band of the current audio frame. And traversing all the sub-bands, calculating the energy of each sub-band, and calculating the total energy of all the sub-bands. And comparing the change of the sub-band energy of each sub-band, and passing through the sequence number and the times of the sub-band of which the sub-band energy of the sub-band with the same sub-band number continuously increases among a plurality of audio frames. If the first number of times that the energy of the current sub-band is continuously increased is larger than a first preset threshold, comparing the sub-band energy of the current sub-band with the preset energy threshold, if the sub-band energy of the current sub-band is larger than the preset energy threshold, detecting howling at the current sub-band, and starting to perform howling suppression processing on the sub-band generated by the howling detected. If the first number of times that the energy of the current sub-band is continuously increased is not larger than a first preset threshold, calculating the proportion of the sub-band energy of the current sub-band to the total energy of all sub-bands, and judging whether the ratio of the sub-band energy of the sub-bands with the same sub-band number is continuously larger than or equal to a second number of times of a preset ratio among multiple frames is larger than a second preset threshold, if so, determining that the current sub-band has howling, and starting howling suppression at the moment.
According to the howling detection and inhibition method, the energy of the obtained sub-band of the audio signal is detected by utilizing the inherent coding and decoding process of the SBC coder-decoder, and the howling is judged and inhibited. Unnecessary processing procedures are reduced, power consumption for howling detection and inhibition on the SBC audio codec is reduced, and computing power is saved.
Fig. 5 shows a schematic structural diagram of an embodiment of the howling detection and suppression device of the present application.
In the embodiment shown in fig. 5, the howling detection and suppression device of the present application includes: an analysis filter bank 501, which performs subband decomposition on the current audio frame input by the SBC encoder to obtain a plurality of subbands, and numbers the subbands in sequence; a howling detection module 502, configured to calculate energy of each subband to obtain subband energy, and compare subband energy corresponding to a subband with the same subband number in a current audio frame and multiple historical audio frames, where a first number of times that subband energy of the current subband in the current audio frame continuously rises relative to subband energy of a historical subband with the same subband number in the historical audio frame is determined, and under a condition that the first number of times is greater than a first preset threshold, it is determined that howling exists at the current subband in the current audio frame; and a howling suppression module 503, which performs howling suppression on the sub-band in which howling exists.
Optionally, in the analysis filter bank 501, during the encoding process of the SBC encoder on the current audio frame, the current audio frame is decomposed by the analysis filter bank in the SBC encoder, so as to obtain a plurality of subbands.
Optionally, in the howling detection module 502, it is determined whether the subband energy of the current subband is greater than the subband energy of the historical subband with the same subband number in the previous historical audio frame, if so, the first number is incremented by one, otherwise, the first number is cleared.
Optionally, in the howling detection module 502, under the condition that the first number is greater than a first preset threshold, whether the subband energy of the current subband is greater than a preset energy threshold is determined; and if so, determining that howling exists at the current sub-band.
Optionally, in the howling detection module 502, under the condition that the first number is not greater than the first preset threshold, sequentially calculating an energy ratio between the subband energy of the current subband and the energy sum of the subband energy of each subband in the current audio frame; determining a second time that the energy ratio of the current sub-band in the current audio frame is continuously larger than or equal to a preset ratio relative to the energy ratio of a historical sub-band with the same sub-band number in the historical audio frame; and under the condition that the second number of times is larger than a second preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting to perform howling suppression.
Optionally, in the howling suppression module 503, the sub-band in the current audio frame where the howling exists is subjected to phase transformation and gain reduction processing through an all-pass filter.
The howling detection and suppression device utilizes the inherent coding and decoding process of the SBC coder decoder to detect the energy of the obtained sub-band of the audio signal and judge and suppress the howling. Unnecessary processing procedures are reduced, power consumption for howling detection and inhibition on the SBC audio codec is reduced, and computing power is saved.
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 described in any 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 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 (8)
1. A howling detection and suppression method, comprising:
carrying out sub-band decomposition on an input current audio frame through an SBC encoder or a decoder to obtain a plurality of sub-bands, and numbering the sub-bands in sequence;
calculating the energy of each sub-band to obtain sub-band energy;
comparing the sub-band energy corresponding to sub-bands with the same sub-band number in the current audio frame and a plurality of historical audio frames, wherein
Sequentially determining the first times that the sub-band energy of each current sub-band in the current audio frame continuously rises relative to the sub-band energy of the historical sub-band with the same sub-band number in the historical audio frame;
under the condition that the first time is not larger than a first preset threshold value, sequentially calculating the energy ratio of the sub-band energy of the current sub-band to the sub-band energy sum of each sub-band in the current audio frame;
Determining a second number of times that the energy ratio of the current sub-band in the current audio frame is continuously greater than or equal to a preset ratio relative to the energy ratio of a historical sub-band with the same sub-band number in the historical audio frame;
and under the condition that the second number is larger than a second preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting howling suppression.
2. The howling detection and suppression method according to claim 1, wherein said performing subband decomposition on the input current audio frame by the SBC encoder to obtain a plurality of subbands comprises:
and decomposing the current audio frame through an analysis filter bank in the SBC encoder in the encoding process of the current audio frame by the SBC encoder to obtain a plurality of sub-bands.
3. The howling detection and suppression method according to claim 1, wherein said sequentially determining a first number of times that the subband energy of each current subband in the current audio frame continuously rises with respect to the subband energy of a history subband having the same subband number in the history audio frame comprises:
and judging whether the sub-band energy of the current sub-band is greater than the sub-band energy of the historical sub-band with the same sub-band number in the previous historical audio frame, if so, adding one to the first time, otherwise, resetting the first time.
4. The howling detection and suppression method according to claim 1, wherein the determining that howling exists in the current audio frame at the current subband and howling suppression is started under the condition that the first number is greater than a first preset threshold further comprises:
judging whether the sub-band energy of the current sub-band is greater than a preset energy threshold value or not under the condition that the first time number is greater than the first preset threshold value;
and if so, determining that howling exists at the current sub-band.
5. The howling detection and suppression method according to any one of claims 1-4, wherein said determining that howling exists in said current audio frame at said current sub-band and starting howling suppression comprises:
and carrying out phase transformation and gain reduction processing on the sub-band with the howling in the current audio frame through an all-pass filter.
6. A howling detection and suppression apparatus, comprising:
the analysis filter bank carries out sub-band decomposition on the current audio frame input by the SBC encoder to obtain a plurality of sub-bands, and the sub-bands are numbered in sequence;
the howling detection module is used for calculating the energy of each sub-band to obtain sub-band energy, comparing the sub-band energy corresponding to the sub-band with the same sub-band number in the current audio frame and a plurality of historical audio frames, determining the first number of times that the sub-band energy of the current sub-band continuously rises relative to the sub-band energy of the historical sub-band with the same sub-band number in the historical audio frames in the current audio frame, and sequentially calculating the energy ratio of the sub-band energy of the current sub-band to the sub-band energy sum of each sub-band in the current audio frame under the condition that the first number of times is not greater than a first preset threshold value; determining a second number of times that the energy ratio of the current sub-band in the current audio frame is continuously larger than or equal to a preset ratio relative to the energy ratio of a historical sub-band with the same sub-band number in the historical audio frame; under the condition that the second number is larger than a second preset threshold value, determining that howling exists in the current sub-band in the current audio frame, and starting howling suppression; and
And the howling suppression module carries out howling suppression on the sub-bands with the howling.
7. A computer readable storage medium storing computer instructions, wherein the computer instructions are operable to perform the howling detection and suppression method of any one of claims 1-5.
8. A computer apparatus comprising a processor and a memory, the memory storing computer instructions, wherein: the processor operates computer instructions to perform the howling detection and suppression method of any one of claims 1-5.
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