Audio signal processing method, apparatus, storage medium, and program product

Abstract

The application provides an audio signal processing method, device, storage medium and program product. The method comprises: obtaining an original audio signal; performing virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal; performing frequency division processing on the virtual bass enhanced audio signal to obtain at least two subband signals; performing dynamic range control (DRC) processing on the at least two subband signals respectively to obtain processed subband signals; and superimposing the processed subband signals and outputting the superimposed signals to a loudspeaker. The application can improve the problem of audio clarity reduction caused by audio virtual bass processing.

Description

TECHNICAL FIELD

[0001] The present application relates to the signal processing technology field, and in particular to an audio signal processing method and device, a storage medium and a program product. BACKGROUND

[0002] With the gradual miniaturization of electronic devices and electronic components, the commonly used output devices of electro-acoustic systems, such as loudspeakers, are also becoming smaller and smaller, which makes multimedia devices more portable, more beautiful and more power saving. However, from the perspective of high fidelity of electro-acoustic systems, small-sized loudspeakers are a great disadvantage, that is, when the size of the loudspeaker and the sound box becomes smaller, the bass cutoff frequency of the loudspeaker will increase, that is, the small-sized loudspeaker cannot effectively reproduce low-frequency sounds below the cutoff frequency.

[0003] To solve this problem, the commonly used method is to use virtual bass technology. The virtual bass technology is based on the "missing fundamental phenomenon" in psychoacoustics, and uses the harmonic series of the fundamental frequency within the effective frequency band of the loudspeaker to restore the fundamental tone and timbre, so as to make the listener have a similar auditory perception of the fundamental tone. At present, the commonly used virtual bass enhancement technology can use time-frequency conversion technology to convert the time domain signal to the frequency domain, generate the harmonics corresponding to the fundamental frequency in the frequency domain, and then convert it to the time domain. This method can accurately control the composition and amplitude of the harmonics, but the transient effect is poor, and it cannot meet the requirements of real-time audio processing occasions which require high real-time performance. In order to solve this problem, in the multimedia playback scene of TV and other real-time performance requirements, a nonlinear device (NLD) algorithm is usually used to nonlinearly process the low-frequency signal to generate harmonics. However, this method will introduce intermodulation distortion to the audio signal with rich harmonic components, in addition, the low-frequency harmonics may cause psychoacoustic masking to the low-amplitude high-frequency signal, reducing the high-frequency component of the auditory perception, and thus leading to the decrease of the audio clarity of the auditory perception. SUMMARY

[0004] The present application provides an audio signal processing method, device, storage medium and program product to improve the problem of decrease of audio clarity caused by virtual bass processing.

[0005] In a first aspect, the present application provides an audio signal processing method, comprising:

[0006] obtaining an original audio signal;

[0007] performing virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal;

[0008] performing frequency division processing on the virtual bass enhanced audio signal to obtain at least two sub-band signals;

[0009] DRC processing is performed on the at least two sub-band signals respectively to obtain processed sub-band signals;

[0010] The processed sub-band signals are superimposed and output to a loudspeaker.

[0011] In the scheme, the amplitude of the sub-band signals can be adjusted by performing DRC processing on the sub-band signals. Since the energy and amplitude of the sub-band signals are related, the dynamic characteristics of the sub-band signals and the relative energy between the sub-bands can be adjusted, thereby improving the problem of audio clarity reduction caused by virtual bass processing. In addition, by using the DRC technology, the possibility of distortion of the virtual bass algorithm itself can be reduced while maximizing the advantages of the virtual bass technology, avoiding unnatural sounds after virtual bass enhancement in some cases, especially when the cutoff frequency of the loudspeaker is very high. The combination of virtual bass and audio dynamic range control can effectively expand the listening range of the loudspeaker, and based on the masking effect of psychoacoustics, the unnatural distortion perceived can be reduced.

[0012] Optionally, the frequency division processing of the virtual bass enhanced audio signal to obtain at least two sub-band signals comprises:

[0013] According to the cutoff frequency of the loudspeaker, the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal is determined;

[0014] According to the cutoff frequency of the virtual bass, a first frequency division point is determined;

[0015] According to the first frequency division point, the frequency division processing of the virtual bass enhanced audio signal is performed to obtain at least two sub-band signals.

[0016] In the scheme, according to the cutoff frequency of the loudspeaker, the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal is determined, and based on the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal, a first frequency division point is determined. Then, the frequency division processing of the virtual bass enhanced audio signal is performed according to the first frequency division point, thereby obtaining at least two sub-band signals. Since the cutoff frequency corresponding to the virtual bass is considered, the virtual bass signal is retained, the dynamic characteristics of the audio signal are adjusted, the clarity of the audio signal is improved, and the tone of the audio signal is improved. In addition, since the cutoff frequency corresponding to the virtual bass is considered, sub-band signals containing main fundamental frequency harmonics and high frequency sub-band signals can be obtained, and their dynamic characteristics can be adjusted respectively, thereby improving the clarity of the audio signal.

[0017] Optionally, the number of sub-band signals is at least three;

[0018] According to the first frequency division point, the virtual bass enhanced audio signal is subjected to frequency division processing to obtain at least three sub-band signals, including:

[0019] According to the system computing resource, the number of frequency division points and corresponding frequency division frequencies of the frequency division points other than the first frequency division point are determined;

[0020] According to the first frequency division point, the number of frequency division points and the frequency division frequencies, the virtual bass enhanced audio signal is subjected to frequency division processing to obtain at least three sub-band signals.

[0021] According to the cutoff frequency of the loudspeaker, the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal is determined, and based on the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal, the first frequency division point is determined, and further considering the system computing resource, the number of frequency division points and corresponding frequency division frequencies of the frequency division points other than the first frequency division point are determined, and according to the first frequency division point, the number of frequency division points and the corresponding frequency division frequencies, the virtual bass enhanced audio signal is subjected to frequency division processing to obtain at least three sub-band signals. Since the cutoff frequency corresponding to the virtual bass is considered, the sub-band signal containing the main fundamental frequency harmonic and the high frequency sub-band signal can be obtained, and their dynamic characteristics are adjusted respectively, so as to improve the clarity of the audio signal. In addition, since the number of frequency division points and the frequency division frequencies can be determined according to the system computing resource, the efficiency of frequency division processing can be improved.

[0022] Optionally, the frequency division processing of the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies to obtain at least three sub-band signals includes:

[0023] According to the first frequency division point, the number of frequency division points and the frequency division frequencies, the virtual bass enhanced audio signal is subjected to frequency division processing by using a linear phase frequency division filter set to obtain the at least three sub-band signals.

[0024] In this scheme, since the linear phase frequency division filter set is used to perform frequency division processing on the virtual bass enhanced audio signal, the distortion of the frequency response of each sub-band signal at the frequency division point can be reduced.

[0025] Optionally, the virtual bass signal processing of the original audio signal to obtain the virtual bass enhanced audio signal includes:

[0026] The original audio signal is subjected to frequency division processing by using a high-pass filter and a low-pass filter to obtain a high frequency signal and a low frequency signal, wherein the cutoff frequency of the high-pass filter is not greater than the cutoff frequency of the loudspeaker, and the cutoff frequency of the low-pass filter is not less than the cutoff frequency of the loudspeaker;

[0027] performing virtual bass signal processing on the low frequency signal to obtain a virtual bass signal;

[0028] performing delay processing on the high frequency signal to obtain a delayed high frequency signal;

[0029] synthesizing the delayed high frequency signal and the virtual bass signal to obtain the virtual bass enhanced audio signal.

[0030] Optionally, the DRC processing on the at least two sub-band signals respectively to obtain the processed sub-band signals comprises:

[0031] performing dynamic range compression processing on a first sub-band signal of the at least two sub-band signals and performing dynamic range expansion processing on other sub-band signals of the at least two sub-band signals except the first sub-band signal to obtain the processed sub-band signals.

[0032] Through the processing in the above scheme, the intelligibility of the audio signal can be further improved.

[0033] In a second aspect, the present application provides an audio signal processing device, comprising:

[0034] an acquisition unit configured to acquire an original audio signal;

[0035] a processing unit configured to perform virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal;

[0036] The processing unit is further configured to perform frequency division processing on the virtual bass enhanced audio signal to obtain at least two sub-band signals.

[0037] The processing unit is further configured to perform DRC processing on the at least two sub-band signals respectively to obtain processed sub-band signals.

[0038] an output unit configured to output the processed sub-band signals to a loudspeaker after superposition.

[0039] Optionally, the processing unit is specifically configured to:

[0040] determine a cutoff frequency of virtual bass in the virtual bass enhanced audio signal according to a cutoff frequency of the loudspeaker;

[0041] determine a first frequency division point according to the cutoff frequency of the virtual bass;

[0042] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point to obtain at least two sub-band signals.

[0043] Optionally, the number of the sub-band signals is at least three.

[0044] The processing unit is specifically configured to:

[0045] determine, according to the system computing resource, a number of frequency division points and corresponding frequency division frequencies of the frequency division points other than the first frequency division point;

[0046] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies, to obtain the at least three sub-band signals.

[0047] Optionally, the processing unit is specifically configured to:

[0048] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies, to obtain the at least three sub-band signals.

[0049] Optionally, the processing unit is specifically configured to:

[0050] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies, to obtain the at least three sub-band signals.

[0051] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies, to obtain the at least three sub-band signals.

[0052] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies, to obtain the at least three sub-band signals.

[0053] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies, to obtain the at least three sub-band signals.

[0054] Optionally, the processing unit is specifically configured to:

[0055] perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the frequency division frequencies, to obtain the at least three sub-band signals.

[0056] In a third aspect, a computer readable storage medium is provided, and the computer readable storage medium stores computer execution instructions. When a processor executes the computer execution instructions, the audio signal processing method in the first aspect is implemented.

[0057] In a fourth aspect, the present application provides a computer program product comprising a computer program which, when executed by a processor, implements the audio signal processing method of the first aspect.

[0058] The audio signal processing method, device, storage medium and program product provided in the present application can improve the problem of audio clarity reduction caused by virtual bass distortion by performing frequency division processing on the virtual bass enhanced audio signal, performing DRC processing on the obtained at least two subband signals, superimposing the processed subband signals to obtain the final audio signal, and feeding back the final obtained audio signal to the loudspeaker. BRIEF DESCRIPTION OF DRAWINGS

[0059] The accompanying drawings, which are incorporated herein and constitute part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0060] Figure 1 A flowchart of an audio signal processing method provided by an embodiment of the present application;

[0061] Figure 2 A flowchart of determining a virtual bass enhanced audio signal provided by an embodiment of the present application;

[0062] Figure 3 An audio input and output amplitude mapping relationship diagram for DRC processing of the first subband signal;

[0063] Figure 4 An audio input and output amplitude mapping relationship diagram for DRC processing of other subband signals;

[0064] Figure 5 A flowchart of another audio signal processing method provided by an embodiment of the present application;

[0065] Figure 6 A flowchart of still another audio signal processing method provided by an embodiment of the present application;

[0066] Figure 7 A principle diagram for processing a virtual bass enhanced audio signal;

[0067] Figure 8 A structural diagram of an audio signal processing device provided by an embodiment of the present application;

[0068] Figure 9 A structural diagram of an electronic device provided by an embodiment of the present application.

[0069] The specific embodiments of the application have been shown by way of example in the above figures, and will be described in greater detail below. These figures and this written description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept to one of ordinary skill in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0070] Exemplary embodiments will be described in detail herein with reference to the attached drawings. The description below is intended to be illustrative of the inventive concept, and is not intended to limit the scope of the inventive concept in any way. Rather, the following description is intended to suggest some aspects of the inventive concept that are consistent with the appended claims.

[0071] At present, there are mainly two ways to improve the bass playback effect of loudspeakers: one is to directly increase the gain of low frequency by using an equalizer (adjustment EQ), which can improve the playback effect of bass to some extent, but the gain amplitude is difficult to control, which can easily cause irreversible damage to the loudspeaker and reduce the service life of the loudspeaker; the other is to use the principle of "missing fundamental phenomenon" in psychoacoustics to perform virtual bass enhancement processing on the audio signal, which can effectively improve the bass perception of the listener by playing the harmonic components of the synthesized bass fundamental frequency while ensuring the normal operation of the small loudspeaker.

[0072] Among them, the virtual bass enhancement method can be divided into two categories: the first category is to use time-frequency conversion technology to convert the time domain signal to the frequency domain, generate the harmonic corresponding to the fundamental frequency in the frequency domain, and then convert it to the time domain. This method can accurately control the harmonic components and amplitude, but the transient effect is poor, and it cannot meet the requirements of real-time audio processing occasions. In order to solve this problem, the second category of technology can be used, that is, a nonlinear device (NLD) algorithm is used to generate harmonics by nonlinearly processing low-frequency signals. The NLD has simple structure and good real-time performance, but it will introduce intermodulation distortion to audio signals with rich harmonic components, resulting in a decrease in audio clarity.

[0073] Based on the above problems, the embodiment of the present application provides an audio signal processing method, which considers that the perceptual clarity of the audio signal is related to the size of the relative energy between the audio and each frequency band, and appropriately increases the amplitude of the high-frequency signal in the virtual bass or appropriately reduces the amplitude of the low-frequency signal in the virtual bass, so that the masking of the generated fundamental harmonic to the high-frequency signal is improved. Therefore, after the original audio signal is subjected to virtual bass enhancement processing, the virtual bass enhanced audio signal obtained is subjected to frequency division processing, at least two sub-band audio signals subjected to the frequency division processing are further subjected to dynamic range control (DRC) processing to adjust the amplitudes (energy and amplitude are directly related) of the sub-band signals, and the problem of audio clarity reduction caused by virtual bass distortion is improved by using the masking effect in psychoacoustics.

[0074] It should be noted that, due to the limitation of the length of the specification, all optional embodiments cannot be enumerated in the specification, and those skilled in the art should be able to think of any combination of technical features as long as the technical features are not contradictory, which can constitute an optional embodiment.

[0075] For example, in one embodiment of embodiment 1, a technical feature a is described, and in another embodiment of embodiment 1, another technical feature b is described. Since the above two technical features are not contradictory, those skilled in the art should be able to think of an embodiment with both features after reading the specification, i.e., a and b.

[0076] The non-contradictory technical features described in different embodiments can also be combined arbitrarily to constitute an optional embodiment.

[0077] For example, technical feature c is described in embodiment 1. In order to control the length of the specification, this technical feature is not described in embodiment 2 and embodiment 3. However, those skilled in the art should be able to think that the audio signal processing method provided in embodiment 2 and embodiment 3 can also include this technical feature after reading the specification.

[0078] The embodiment 1, the embodiment 2 and the embodiment 3 will be described in detail below.

[0079] Embodiment 1

[0080] The embodiment of the present application discloses an audio signal processing method, which is applied to an electronic device with an audio external playing function such as a small speaker, or an electronic device containing a small speaker. The audio signal processing method provided by the embodiment of the present application will be described in detail below. Figure 1 The audio signal processing method provided by the embodiment of the present application will be described in detail.

[0081] Figure 1 A flowchart of an audio signal processing method disclosed in an embodiment of the present application. The method comprises the following steps:

[0082] Step 101: obtaining an original audio signal.

[0083] Step 102: performing virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal.

[0084] After the electronic device obtains the original audio signal to be played, the low frequency signal in the original audio signal is processed by virtual bass signal processing, so as to improve the bass effect of the hearing perception when the electronic device plays the audio signal.

[0085] Exemplarily, Figure 2 A flowchart for determining a virtual bass enhanced audio signal provided by an embodiment of the present application is shown in FIG. 2. When performing virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal, the following steps can be included: Figure 2

[0086] Step 1021: performing frequency band division filtering processing on the original audio signal by a high-pass filter and a low-pass filter respectively to obtain a high frequency signal and a low frequency signal.

[0087] The cut-off frequency of the high-pass filter for obtaining the high frequency signal is not greater than the cut-off frequency of the loudspeaker, and the cut-off frequency of the low-pass filter for obtaining the low frequency signal is not less than the cut-off frequency of the loudspeaker.

[0088] Step 1022: performing virtual bass signal processing on the low frequency signal to obtain a virtual bass signal.

[0089] Step 1023: performing delay processing on the high frequency signal to obtain a delayed high frequency signal.

[0090] Step 1024: synthesizing the delayed high frequency signal and the virtual bass signal to obtain a virtual bass enhanced audio signal.

[0091] Specifically, the original audio signal is first subjected to frequency band division filtering processing by a high-pass filter and a low-pass filter respectively to obtain two parts of a high frequency signal and a low frequency signal. Further, a harmonic generation algorithm can be used to generate each high-order harmonic that can be responded by the loudspeaker from the obtained low frequency signal, so as to obtain a virtual bass signal. The virtual bass signal is then superimposed with the delayed high frequency signal to generate a final enhanced virtual bass signal, i.e., a virtual bass enhanced audio signal.

[0092] Step 103: performing frequency division processing on the virtual bass enhanced audio signal to obtain at least two sub-band signals.

[0093] ​The more the number of sub-band signals after frequency division is, the more details of high-frequency signal processing can be.

[0094] For example, a sub-band filter set is arranged in the electronic device, and the sub-band filter set is composed of N band-pass filters. The cutoff frequency of the band-pass filter is set according to the cutoff frequency f0 of the audio device (for example, a loudspeaker) in the electronic device. The electronic device processes the audio signal X in (n) for virtual bass enhancement through the sub-band filter set to obtain N sub-band signals Xb i (n). i (n) represents the i-th sub-band signal, where i = 1, 2, 3,..., N.

[0095] Step 104: Perform DRC processing on the at least two sub-band signals respectively to obtain processed sub-band signals.

[0096] The DRC technology can map the dynamic range of the input audio amplitude to a preset dynamic range, thereby controlling the amplitude of the audio signal.

[0097] In this step, the perceptual clarity of the audio signal is related to the size of the relative energy between the frequency bands of the audio signal, and appropriately increasing the amplitude of the high-frequency signal or appropriately reducing the amplitude of the virtual bass low-frequency signal can improve the masking of the generated fundamental frequency harmonics to the medium and high-frequency signals. Therefore, the electronic device can perform DRC processing on the sub-band signals to adjust the amplitudes of the sub-band signals to change the relative energy size between the sub-band signals and the dynamic characteristics of the sub-band signals, thereby improving the overall clarity of the audio signal.

[0098] In one possible implementation, when performing DRC processing on the at least two sub-band signals, dynamic range compression processing in DRC can be performed on a first sub-band signal in the at least two sub-band signals, and dynamic range expansion processing in DRC can be performed on other sub-band signals in the at least two sub-band signals except the first sub-band signal, thereby obtaining the processed sub-band signals.

[0099] To better improve the clarity, the amplitude of the first sub-band signal can be compressed to reduce the amplitude of the first sub-band signal. In addition, the amplitudes of other high-frequency sub-band signals except the first sub-band signal can be expanded to increase the amplitudes of the other high-frequency sub-band signals.

[0100] Figure 3 The amplitude mapping relationship between the audio input and output of the DRC processing of the first sub-band signal is shown in FIG. 2. Figure 3As shown, for the input signal with amplitude less than -30dB, the original amplitude is directly output, but for the input signal with amplitude from -30dB to 0dB, the amplitude of the output signal can be linearly mapped from -30dB to -5dB. Here, the linear mapping processing manner is: assuming that the input signal amplitude is x dB, then the output signal amplitude is: y = -30 + (x - (-30)) * (-5 - (-30)) / (0 - (-30)) dB; and for the input signal higher than -5dB, the amplitude of the output signal is controlled to be -5dB.

[0101] Figure 4 The amplitude mapping relationship between the audio input and output for the DRC processing of other subband signals is shown in FIG. 4. Figure 4 As shown, for the input signal with amplitude less than -50dB, the amplitude of the output signal is linearly increased by 30dB; for the input signal with amplitude from -50dB to 0dB, the amplitude of the output signal is linearly mapped from -20dB to 0dB. Here, the linear mapping processing manner is: assuming that the input signal amplitude is x dB, then the output signal amplitude is: y = -20 + (x - (-50)) * (0 - (-20)) / (0 - (-50)) dB; and for the input signal higher than 0dB, the amplitude of the output signal can be set to 0dB.

[0102] It should be understood that, Figure 3 and Figure 4 The values in the above tables are only examples, and in actual applications, the dynamic range control manner of the first subband signal and other subband signals can also use other mapping relationships for control. In actual applications, the mapping relationship between the input and output of different subband signals needs to be adjusted according to actual conditions. Here, the DRC processing parameters of the two subbands are not specifically limited.

[0103] In this step, since the perceptual clarity of the audio signal is related to the relative energy size between the frequency bands of the audio signal, and appropriately increasing the amplitude of the high-frequency signal or appropriately reducing the amplitude of the virtual bass low-frequency signal can improve the masking of the generated fundamental frequency harmonics to the medium and high-frequency signals. Therefore, the electronic device can perform DRC processing on the subband signals, adjust the amplitudes of the subband signals, change the relative energy size between the subband signals and the dynamic characteristics of the subband signals, and thus improve the overall clarity of the audio signal.

[0104] Step 105: superimposing the processed subband signals and outputting to the loudspeaker.

[0105] In this step, after performing DRC processing on the subband signals to obtain the processed subband signals, the processed subband signals are superimposed in the time domain to obtain the final audio signal, and the audio signal is input to the loudspeaker for output.

[0106] The audio signal processing method provided in the embodiments of the present application can improve the problem of audio clarity reduction caused by virtual bass distortion by adjusting the amplitude of the subband signals and adjusting the dynamic characteristics of the subband signals and the relative energy between the subbands, because the energy of the subband signals is related to the amplitude of the subband signals. In addition, the double combination of virtual bass and high frequency dynamic range compression can effectively expand the listening range of the loudspeaker by changing the relative energy between the middle-high frequency subband and the low frequency subband (the subband containing the harmonic component), and can also weaken or even eliminate the audible distortion by using the masking effect in psychoacoustics.

[0107] Embodiment 2

[0108] Figure 5 The flowchart of another audio signal processing method provided in the embodiments of the present application is described below. Figure 1 The process of performing frequency division processing on the virtual bass enhanced audio signal to obtain two subband signals in step 103 of the embodiment shown in the figure is described. As shown in the figure, the embodiment includes: Figure 5

[0109] Step 501: obtaining an original audio signal.

[0110] Step 502: performing virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal.

[0111] Steps 501-502 are similar to steps 101-102, and will not be described here.

[0112] Step 503: determining the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal according to the cutoff frequency of the loudspeaker.

[0113] In this step, the cutoff frequency of the loudspeaker is related to the volume of the loudspeaker, wherein the smaller the volume, the higher the cutoff frequency of the loudspeaker.

[0114] Specifically, the cutoff frequency of the loudspeaker can be increased by a first preset threshold to obtain the cutoff frequency f0 of the virtual bass in the virtual bass enhanced audio signal.

[0115] Step 504: determining a first frequency division point according to the cutoff frequency of the virtual bass.

[0116] ​In the virtual bass algorithm, the first three high frequency harmonics (2nd, 3rd and 4th harmonics) have the greatest contribution to the perceived virtual bass. In order to maintain the bass perception enhancement effect of the virtual bass, the first frequency point f1 can be set to be greater than or equal to 4f0 in practical applications.

[0117] In the embodiment, the cutoff frequency of the virtual bass can be determined based on the cutoff frequency of the loudspeaker, and then the first frequency point can be determined based on the cutoff frequency of the virtual bass. The virtual bass perception of the audio can be maintained by considering the cutoff frequency of the virtual bass.

[0118] Step 505: The virtual bass enhanced audio signal is frequency-processed based on the first frequency point to obtain two sub-band signals.

[0119] In this step, after the first frequency point is determined, two linear phase bandpass filters are generated based on the first frequency point to perform frequency band filtering on the virtual bass enhanced audio signal to obtain two sub-band signals. The frequency range of the first bandpass filter is 20Hz-f1, and the frequency range of the second bandpass filter is f1-fs / 2, where fs is the sampling frequency of the audio signal.

[0120] For example, assuming that the first frequency point is 300Hz and the frequency range of the virtual bass enhanced audio signal is 20Hz-20KHz, the virtual bass enhanced audio signal is frequency-processed based on the first frequency point to obtain two sub-band signals, where the frequency range of the first sub-band signal is 20Hz-300Hz and the frequency range of the second sub-band signal is 300Hz-20KHz.

[0121] Step 506: The two sub-band signals are respectively subjected to DRC processing to obtain processed sub-band signals.

[0122] In this step, after the virtual bass enhanced audio signal is frequency-processed to obtain two sub-band signals, the two sub-band signals are respectively subjected to DRC processing.

[0123] For example, the dynamic range compression processing in DRC can be performed on the first sub-band signal, which can be performed in the manner shown in FIG. 4, and details are not described herein. The dynamic range expansion processing in DRC can be performed on the second sub-band signal, which can be performed in the manner shown in FIG. 5, and details are not described herein. It should be understood that the DRC processing parameters of the two sub-band signals can be adjusted as required in practical applications. The DRC processing parameters of the two sub-band signals are not specifically limited herein. Figure 3 Figure 4 Step 507: The processed sub-band signals are superimposed and output to the loudspeaker.

[0124] Step 507: The processed sub-band signals are superimposed and output to the loudspeaker.​

[0125] In this step, the two DRC-processed sub-band signals can be superimposed in time domain, for example, the amplitudes of the two DRC-processed sub-band signals can be added. The superimposed signal is transmitted to the loudspeaker for output. Since the dynamic characteristics and relative energy of the sub-band containing the harmonic signal generated by the virtual bass algorithm and the mid-high frequency sub-band are changed, the intelligibility of the audio signal can be improved.

[0126] In this embodiment, according to the cutoff frequency of the loudspeaker, the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal is determined, and based on the cutoff frequency of the virtual bass, the first frequency division point can be determined. Then, the virtual bass enhanced audio signal is frequency-division processed according to the first frequency division point, so as to obtain two sub-band signals. Since the cutoff frequency corresponding to the virtual bass is considered, on the one hand, the bass listening effect of the virtual bass can be maximally preserved, and on the other hand, the dynamic range of the mid-high frequency audio signal is improved, and finally the overall intelligibility of the audio signal is improved.

[0127] Embodiment 3

[0128] Figure 6 Another flowchart of an audio signal processing method provided by the embodiment of the present application is shown in the figure. Based on the embodiment shown in the figure, the process of frequency-division processing the virtual bass enhanced audio signal in step 103 to obtain at least three sub-band signals is described. Figure 1 As shown in the figure, the embodiment includes: Figure 6

[0129] Step 601: obtaining an original audio signal.

[0130] Step 602: performing virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal.

[0131] Step 603: determining the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal according to the cutoff frequency of the loudspeaker.

[0132] Step 604: determining the first frequency division point according to the cutoff frequency of the virtual bass.

[0133] Steps 601-604 are similar to steps 501-504, which will not be described here.

[0134] Step 605: determining the number and frequency of the frequency division points other than the first frequency division point according to the system computing resources.

[0135] ​In this step, the system computing resource may be, for example, the computing capability of the central processing unit (CPU) of the electronic device, the occupation of the digital signal processing (DSP) resource, or the occupation rate of the memory, etc. The number of frequency division points of the frequency division points other than the first frequency division point is related to the condition of the system computing resource. The electronic device may determine the number of frequency division points corresponding to different conditions of each system computing resource according to a pre-set correspondence relationship, and the frequency division frequency corresponding to each frequency division point.

[0136] For example, if the computing capability of the CPU of the electronic device is strong, three additional frequency division points other than the first frequency division point may be set, which are 2Khz, 6Khz and 10Khz respectively. If the computing capability of the CPU of the electronic device is general, two additional frequency division points other than the first frequency division point may be set, which are 2Khz and 6Khz respectively. If the computing capability of the CPU of the electronic device is weak, only one frequency division point other than the first frequency division point may be set, and the specific value of the frequency division point may be 2Khz.

[0137] When the system computing resource is the occupation of the DSP resource or the occupation rate of the memory, the setting mode of the number of frequency division points and the corresponding frequency division frequency is similar to that when the system computing resource is the computing capability of the CPU. Here, no longer be repeated.

[0138] Step 606: performing frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the corresponding frequency division frequency to obtain at least three sub-band signals.

[0139] In this step, if the first frequency division point determined and the number of frequency division points determined according to the system computing resource are N, and the first frequency division point is f1 and the subsequent frequency division point is fn, where n is 2, 3, …, N, then a frequency division filter bank may be generated according to the N frequency division points, where the frequency division filter bank may be composed of N+1 sub-band filters.

[0140] In a possible implementation, the implementation of the above frequency division filter bank may adopt a linear phase frequency division filter bank. Therefore, the electronic device may perform frequency division band filtering processing on the virtual bass enhanced audio signal by using the linear phase frequency division filter bank according to the determined first frequency division point f1 and the subsequent frequency division point fn, so as to obtain N+1 sub-band signals.

[0141] Since the linear phase frequency division filter bank is used to perform frequency division band filtering processing on the virtual bass enhanced audio signal, the distortion of the frequency response of each sub-band signal at the frequency division point may be reduced.

[0142] Step 607: Perform DRC processing on at least three sub-band signals respectively to obtain the processed sub-band signals.

[0143] Figure 7 This is a schematic diagram illustrating the principle of processing audio signals for virtual bass enhancement, as shown below. Figure 7 As shown, based on the multi-band crossover point, the virtual bass-enhanced audio signal is input to a linear phase crossover filter bank for frequency band filtering, resulting in N+1 sub-band signals, where N is a positive integer. Each of the N+1 sub-band signals is then processed using DRC (Dynamic Range Compression). For example, sub-band signal 1 can be processed using DRC dynamic range compression; details can be found in [reference needed]. Figure 3 The method shown is as described and will not be elaborated further here. Dynamic range extension processing in DRC can be applied to sub-band signals 2 through N+1; for details, please refer to [reference needed]. Figure 4 The procedure is as shown and will not be elaborated further here. It should be understood that in practical applications, the DRC processing parameters for the N+1 sub-band signals can be adjusted as needed. No specific restrictions are placed on the DRC processing parameters for the two sub-bands here.

[0144] Step 608: The processed sub-band signals are superimposed and then output to the speaker.

[0145] In this step, continue to refer to Figure 7 As shown, the N+1 sub-band signals that have undergone DRC processing can be superimposed, and the superimposed audio output signal can be transmitted to the speaker for playback.

[0146] For example, assuming the first crossover point is 300Hz, the second and third crossover points are 2kHz and 6kHz respectively, and the frequency range of the virtual bass-enhanced audio signal is 20Hz-20kHz, then after crossover processing the virtual bass-enhanced audio signal according to the first, second, and third crossover points, four sub-band signals are obtained: the first sub-band signal (20Hz-300Hz), the second sub-band signal (300Hz-2kHz), the third sub-band signal (2kHz-6kHz), and the fourth sub-band signal (6kHz-20kHz). Since the lower-frequency first sub-band signal mainly focuses on the harmonic-dominated frequency band of the virtual bass processing, and the higher-frequency second, third, and fourth sub-band signals have a greater impact on the clarity of the audio signal, the electronic device will refer to the first sub-band signal... Figure 3 The DRC input-output mapping relationship shown is used for DRC processing, and the remaining sub-band signals are referenced. Figure 4The DRC input and output mapping relationship is shown to perform DRC processing. The DRC-processed subband signals are superimposed, and the finally superimposed signal is output through a loudspeaker. The DRC input and output mapping relationship of each subband signal is not specifically limited here, and in actual application, the mapping relationship can be adjusted according to actual conditions.

[0147] In this embodiment, according to the cutoff frequency of the loudspeaker, the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal is determined, and then based on the cutoff frequency of the virtual bass in the virtual bass enhanced audio signal, the first frequency division point is determined. Further, the system computing resources are considered, and the number and frequency of the other frequency division points are determined according to the system computing resources, so that the virtual bass enhanced audio signal is frequency-division processed according to the final number and frequency of the frequency division points, to obtain at least three subband signals. Since the cutoff frequency corresponding to the virtual bass is considered, the bass listening effect of the virtual bass can be preserved, and on the other hand, the dynamic range of the mid-high frequency audio signal is improved, and finally the overall clarity of the audio signal is improved.

[0148] Figure 8 A structural schematic diagram of an audio signal processing device 80 provided in the embodiments of the present application is shown in the figure, for example, see Figure 8 As shown in the figure, the audio signal processing device 80 can include:

[0149] The acquisition unit 11 is configured to acquire an original audio signal.

[0150] The processing unit 12 is configured to perform virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal.

[0151] The processing unit 12 is further configured to perform frequency division processing on the virtual bass enhanced audio signal to obtain at least two subband signals.

[0152] The processing unit 12 is further configured to perform dynamic range control (DRC) processing on the at least two subband signals respectively to obtain processed subband signals.

[0153] The output unit 13 is configured to superimpose the processed subband signals and output them to a loudspeaker.

[0154] The audio signal processing device 80 provided in the embodiments of the present application can execute the technical solutions of the audio signal processing method in any of the above embodiments, and the implementation principles and beneficial effects thereof are similar to those of the audio signal processing method. For details, refer to the implementation principles and beneficial effects of the audio signal processing method, which will not be described here.

[0155] Optionally, the processing unit 12 is specifically configured to:

[0156] determine a cutoff frequency of the virtual bass in the virtual bass enhanced audio signal according to a cutoff frequency of the loudspeaker;

[0157] determine a first crossover point according to the cutoff frequency of the virtual bass;

[0158] crossover process the virtual bass enhanced audio signal according to the first crossover point to obtain at least two sub-band signals.

[0159] Optionally, the number of the sub-band signals is at least three.

[0160] The processing unit 12 is specifically configured to:

[0161] determine a number of crossover points and corresponding crossover frequencies of the crossover points other than the first crossover point according to system computing resources;

[0162] crossover process the virtual bass enhanced audio signal according to the first crossover point, the number of the crossover points and the crossover frequencies to obtain the at least three sub-band signals.

[0163] Optionally, the processing unit 12 is specifically configured to:

[0164] crossover process the virtual bass enhanced audio signal according to the first crossover point, the number of the crossover points and the crossover frequencies by using a linear phase crossover filter bank to obtain the at least three sub-band signals.

[0165] Optionally, the processing unit 12 is specifically configured to:

[0166] crossover process the original audio signal by using a high-pass filter and a low-pass filter respectively to obtain a high-frequency signal and a low-frequency signal, wherein a cutoff frequency of the high-pass filter is not greater than a cutoff frequency of the loudspeaker, and a cutoff frequency of the low-pass filter is not less than the cutoff frequency of the loudspeaker.

[0167] process the low-frequency signal to obtain a virtual bass signal;

[0168] delay process the high-frequency signal to obtain a delayed high-frequency signal;

[0169] combine the delayed high-frequency signal and the virtual bass signal to obtain the virtual bass enhanced audio signal.

[0170] Optionally, the processing unit 12 is specifically configured to:

[0171] The dynamic range compression in the DRC is applied to a first subband signal of the at least two subband signals, and the dynamic range expansion in the DRC is applied to other subband signals of the at least two subband signals except the first subband signal, to obtain the processed subband signals.

[0172] The audio signal processing apparatus 80 provided by the embodiments of the present application can execute the technical solutions of the audio signal processing method in any of the above embodiments, and the implementation principle and beneficial effects thereof are similar to those of the audio signal processing method. For details, refer to the implementation principle and beneficial effects of the audio signal processing method, which will not be described here again.

[0173] Figure 9 An example of a structural schematic diagram of an electronic device 90 is shown in FIG. 8. Figure 9 As shown in the figure, the electronic device can include a processor 901 and a memory 902; wherein,

[0174] The memory 902 is configured to store a computer program.

[0175] The processor 901 is configured to read the computer program stored in the memory 902, and execute the technical solutions of the audio signal processing method in any of the above embodiments according to the computer program in the memory 902.

[0176] Optionally, the memory 902 can be independent or integrated with the processor 901. When the memory 902 is independent of the processor 901, the electronic device can further include a bus for connecting the memory 902 and the processor 901.

[0177] Optionally, the present embodiment further includes a communication interface, which can be connected with the processor 901 through the bus. The processor 901 can control the communication interface to realize the functions of acquisition and sending of the above electronic device.

[0178] The electronic device shown in the embodiments of the present application can execute the technical solutions of the audio signal processing method in any of the above embodiments, and the implementation principle and beneficial effects thereof are similar to those of the audio signal processing method. For details, refer to the implementation principle and beneficial effects of the audio signal processing method, which will not be described here again.

[0179] The embodiment of the present application further provides a computer readable storage medium, which stores computer execution instructions, and when a processor executes the computer execution instructions, the technical solution of the audio signal processing method in any of the above embodiments is realized, the implementation principle and beneficial effects of which are similar to those of the audio signal processing method. For details, refer to the implementation principle and beneficial effects of the audio signal processing method, which will not be repeated here.

[0180] The embodiment of the present application further provides a computer program product, which comprises a computer program, and when a processor executes the computer program, the technical solution of the audio signal processing method in any of the above embodiments is realized, the implementation principle and beneficial effects of which are similar to those of the audio signal processing method. For details, refer to the implementation principle and beneficial effects of the audio signal processing method, which will not be repeated here.

[0181] Other embodiments of the present application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. The specification and examples given are exemplary only and the true scope and spirit of the application is indicated by the following claims. It will be appreciated by persons skilled in the art that numerous variations and / or modifications can be made to the application as described above without departing from the scope or spirit of the application. It is intended that all such variations and / or modifications be included within the scope of the application. Other embodiments are possible and herein disclosed.

[0182] It should be understood that the application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application is limited only by the appended claims.

Claims

1. A method of audio signal processing, characterized by, The method comprises: obtaining an original audio signal; performing virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal; performing frequency division processing on the virtual bass enhanced audio signal to obtain at least two sub-band signals; respectively performing dynamic range control (DRC) processing on the at least two sub-band signals to obtain processed sub-band signals; superimposing the processed sub-band signals and outputting the superimposed signals to a loudspeaker; the frequency division processing on the virtual bass enhanced audio signal to obtain at least two sub-band signals comprises: determining a cutoff frequency of virtual bass in the virtual bass enhanced audio signal according to a cutoff frequency of the loudspeaker; determining a first frequency division point according to the cutoff frequency of the virtual bass; performing frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point to obtain at least two sub-band signals; the DRC processing on the at least two sub-band signals to obtain processed sub-band signals comprises: performing dynamic range compression processing on a first sub-band signal in the at least two sub-band signals by using DRC, and performing dynamic range expansion processing on other sub-band signals in the at least two sub-band signals except the first sub-band signal by using DRC to obtain the processed sub-band signals.

2. The method of claim 1, wherein, The number of the sub-band signals is at least three; the frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point to obtain at least three sub-band signals comprises: determining the number of frequency division points and corresponding frequency division frequencies of frequency division points other than the first frequency division point according to system computing resources; performing frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the corresponding frequency division frequencies to obtain the at least three sub-band signals.

3. The method of claim 2, wherein, the frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point, the number of frequency division points and the corresponding frequency division frequencies to obtain the at least three sub-band signals comprises: performing frequency division processing on the virtual bass enhanced audio signal by using a linear phase frequency division filter bank according to the first frequency division point, the number of frequency division points and the corresponding frequency division frequencies to obtain the at least three sub-band signals.

4. The method according to any one of claims 1 to 3, characterized in that, The virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal comprises: performing frequency division processing on the original audio signal by using a high-pass filter and a low-pass filter to obtain a high-frequency signal and a low-frequency signal, wherein the cutoff frequency of the high-pass filter is not greater than the cutoff frequency of the loudspeaker, and the cutoff frequency of the low-pass filter is not less than the cutoff frequency of the loudspeaker; performing virtual bass signal processing on the low-frequency signal to obtain a virtual bass signal; performing delay processing on the high-frequency signal to obtain a delayed high-frequency signal; combining the delayed high-frequency signal and the virtual bass signal to obtain the virtual bass enhanced audio signal.

5. An audio signal processing apparatus, characterized by comprising: The method comprises: an obtaining unit configured to obtain an original audio signal; The processing unit is configured to perform virtual bass signal processing on the original audio signal to obtain a virtual bass enhanced audio signal. The processing unit is further configured to perform frequency division processing on the virtual bass enhanced audio signal to obtain at least two sub-band signals. The processing unit is further configured to perform DRC processing on the at least two sub-band signals respectively to obtain processed sub-band signals. The output unit is configured to output the processed sub-band signals to a loudspeaker in a superposition manner. The processing unit is specifically configured to: determine a cutoff frequency of virtual bass in the virtual bass enhanced audio signal according to a cutoff frequency of the loudspeaker; determine a first frequency division point according to the cutoff frequency of the virtual bass; perform frequency division processing on the virtual bass enhanced audio signal according to the first frequency division point to obtain at least two sub-band signals; perform dynamic range compression processing on a first sub-band signal of the at least two sub-band signals and perform dynamic range expansion processing on other sub-band signals of the at least two sub-band signals except the first sub-band signal to obtain the processed sub-band signals.

6. An electronic device, comprising: The computer readable storage medium stores a computer program. The computer readable storage medium stores a computer program. The computer readable storage medium stores a computer program.

7. A computer-readable storage medium, characterized in that, The computer program is executed by the processor to implement the audio signal processing method in any one of claims 1-4.

8. A computer program product comprising a computer program, characterized in that, ​

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