JP2015045888A - Audio signal switching method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for switching an audio signal.SOLUTION: A method for switching an audio signal includes: a step (101) for weighting a first high frequency band signal of the audio signal of a current frame and a second high frequency band signal of the audio signal of previous M frames to obtain a processed first high frequency band signal when the audio signal is switched; and a step (102) for synthesizing the processed first high frequency band signal and a first low frequency band signal of the audio signal of the current frame into a wide frequency band signal.

Description

  This application claims priority of Chinese Patent Application No. 201010163406.3 entitled “METHOD AND APPARATUS FOR SWITCHING SPEECH OR AUDIO SIGNALS” filed on April 28, 2010, which is incorporated herein by reference in its entirety. To do.

  The present invention relates to communication technology, and more particularly to a method and apparatus for switching audio signals.

  Currently, during the process of transmitting audio signals over the network, the network conditions may be different, so the network may intercept the bit stream of the audio signal transmitted from the encoder to the network at various bit rates, and as a result The decoder may decode audio signals having different bandwidths from the intercepted bitstream.

  In the prior art, since an audio signal transmitted over a network has various bandwidths, bidirectional switching between a narrow frequency band audio signal and a wide frequency band audio signal occurs during the audio signal transmission process. There is. In an embodiment of the present invention, a narrow frequency band signal is switched to a wide frequency band signal having only low frequency band elements by upsampling and low pass filter processing. The wide frequency band audio signal includes both low frequency band signal elements and high frequency band signal elements.

    International Publication No. 2009/056027

  During the practice of the present invention, the inventor has discovered at least the following problems in the prior art. High frequency band signal information can be obtained as a wide frequency band audio signal, but it does not exist in a narrow frequency band audio signal. Therefore, when an audio signal having various bandwidths is switched, a sudden change in energy occurs in the audio signal. The listening comfort may deteriorate, and as a result, the quality of the audio signal received by the user may deteriorate.

  Embodiments of the present invention present a method and apparatus for switching audio signals that smoothly switches audio signals between various bandwidths, thereby improving the quality of the audio signals received by the user.

Methods for switching audio signals include:
When audio signal switching occurs, the first high frequency band signal of the current audio signal frame and the second high frequency band signal of the previous M (M is 1 or more) audio signal frames are weighted. Obtaining a processed first high frequency band signal; and synthesizing the processed first high frequency band signal and the first low frequency band signal of the frame of the current audio signal into a wide frequency band signal.

An apparatus for switching audio signals includes:
When audio signal switching occurs, the first high frequency band signal of the current audio signal frame and the second high frequency band signal of the previous M (M is 1 or more) audio signal frames are weighted. A processing module configured to obtain a processed first high frequency band signal and a first low frequency band signal of the frame of the processed first high frequency band signal and the current audio signal into a wide frequency band signal; A first synthesis module configured to:

  By using the method and apparatus for switching audio signals in an embodiment of the present invention, the first high frequency band signal of the frame of the current audio signal is the second high frequency of the frame of the previous M audio signals. Processed according to the band signal, so that the second high frequency band signal of the frame of the previous M audio signals can be smoothly switched to the processed first high frequency band signal, the processed first high frequency band signal The first low frequency band signal is combined with the wide frequency band signal. In this way, during the process of switching between audio signals with different bandwidths, such audio signals can be switched smoothly, thereby reducing the negative effects of sudden changes in energy on the subjective audio quality of the audio signal. The quality of the audio signal received by the user can be improved.

  BRIEF DESCRIPTION OF THE DRAWINGS To clarify the technical solutions of the present invention, the accompanying drawings illustrating the embodiments of the present invention will be outlined below. Apparently, the accompanying drawings are merely examples, and those skilled in the art will be able to derive other drawings from such accompanying drawings without creative efforts.

2 is a flowchart of a first embodiment of a method for switching an audio signal. 6 is a flowchart of a second embodiment of a method for switching an audio signal. 3 is a flowchart of the embodiment of step 201 shown in FIG. 4 is a flowchart of the embodiment of step 302 shown in FIG. FIG. 4 is a second flowchart of another embodiment of step 302 shown in FIG. 3 is a flowchart of the embodiment of step 202 shown in FIG. 3 is a second flowchart of another embodiment of step 201 shown in FIG. 4 is a third flowchart of another embodiment of step 201 shown in FIG. 1 is a diagram illustrating a structure of a first embodiment of an apparatus for switching audio signals. FIG. FIG. 6 is a diagram illustrating a structure of a second embodiment of an apparatus for switching audio signals. FIG. 6 is a first schematic diagram showing the structure of a processing module in a second embodiment of an apparatus for switching audio signals. FIG. 5 is a schematic diagram showing a structure of a first module in a second embodiment of the device for switching an audio signal. FIG. 10 is a second schematic diagram showing the structure of a processing module in the second embodiment of the apparatus for switching audio signals. FIG. 10 is a third schematic diagram showing the structure of a processing module in the second embodiment of the apparatus for switching audio signals.

  In order to make the objects, technical solutions and advantages of the present invention easier to understand, the present invention will be described in detail below with reference to embodiments and the accompanying drawings. Apparently, the embodiments are merely examples, and the present invention is not limited to such embodiments. One skilled in the art can derive other embodiments from the embodiments given herein without making significant creative efforts, all such embodiments falling within the scope of the present specification.

  FIG. 1 is a flowchart of a first embodiment of a method for switching audio signals. As shown in FIG. 1, by using a method for switching audio signals, each frame after the switching frame is processed according to the following steps when the audio switching occurs.

  Step 101: When audio switching occurs, weight the first high frequency band signal of the current audio signal frame and the second high frequency band signal of the previous M (M is 1 or more) audio signal frames Then, the processed first high frequency band signal is acquired.

  Step 102: Synthesize the processed first high frequency band signal and the first low frequency band signal of the frame of the current audio signal into a wide frequency band signal.

  In this embodiment, the previous M audio signal frames refer to the M audio signal frames prior to the current frame. The frame of L audio signals before switching indicates the frame of L audio signals before the switching frame when the audio is switched. The current voice frame is a wide frequency band signal, but the previous voice frame is a narrow frequency band signal, or the current voice frame is a narrow frequency band signal, but the previous voice frame is a wide frequency band signal. In some cases, the audio signal is switched and the current audio frame is a switching frame.

  By using the method for switching audio signals in this embodiment, the first high frequency band signal of the frame of the current audio signal is processed according to the second high frequency band signal of the frame of the previous M audio signals. As a result, the second high frequency band signal of the frame of the previous M audio signals can be smoothly switched to the processed first high frequency band signal. In this way, during the process of switching between audio signals having various bandwidths, the high frequency band signals of such audio signals can be switched smoothly. Finally, the processed first high frequency band signal and first low frequency band signal are combined into a wide frequency band signal, and the wide frequency band signal is transmitted to the user terminal, so that the user enjoys a high quality audio signal. can do. By using the method for switching audio signals in this embodiment, it is possible to smoothly switch audio signals having various bandwidths, and thereby influence the sudden change of energy on the subjective audio quality of the audio signal. The quality of the audio signal received by the user can be improved.

  FIG. 2 is a flowchart of a second embodiment of a method for switching audio signals. As shown in FIG. 2, the method includes the following steps.

  Step 200: When no audio signal switching occurs, the first high frequency band signal and the first low frequency band signal of the frame of the current audio signal are combined into a wide frequency band signal.

  Specifically, the first frequency band audio signal in this embodiment may be a wide frequency band audio signal or a narrow frequency band audio signal. When the first frequency band audio signal is not switched during transmission of the audio signal, the operation can be performed according to the following two cases. 1. When the first frequency band audio signal is a wide frequency band audio signal, the low frequency band signal and the high frequency band signal of the wide frequency band audio signal are combined with the wide frequency band signal. 2. When the first frequency band audio signal is a narrow frequency band audio signal, the low frequency band signal and the high frequency band signal of the narrow frequency band audio signal are combined into a wide frequency band signal. In this case, the signal is a wide frequency band signal, but the high frequency band is null.

  Step 201: When the audio signal is switched, the first high frequency band signal of the current audio signal frame and the second high frequency band signal of the previous M audio signal frames are weighted and processed first. 1 Acquire a high frequency band signal. M is 1 or more.

  Specifically, when a switch occurs between audio signals having various bandwidths, the first high frequency band signal of the current audio signal frame is changed to the second high frequency of the previous M audio signal frames. As a result, the second high frequency band signal of the previous M audio signal frames can be smoothly switched to the processed first high frequency band signal. For example, when the wide frequency band audio signal is switched to the narrow frequency band audio signal, the high frequency band signal information corresponding to the narrow frequency band audio signal is null, so the high frequency band signal corresponding to the narrow frequency band audio signal is It is necessary to restore the above-mentioned elements so that the wide frequency band audio signal can be smoothly switched to the narrow frequency band audio signal. On the other hand, when the narrow frequency band audio signal is switched to the wide frequency band audio signal, the high frequency band signal of the wide frequency band audio signal is not null. The energy of the frequency band signal is weakened, and the narrow frequency band audio signal can be smoothly switched to the wide frequency band audio signal. As a result, the high frequency band signal of the wide frequency band audio signal becomes a true high frequency band signal. It must be possible to switch gradually. By processing the frame of the current audio signal in step 201, it is possible to smoothly switch the high frequency band signal of the audio signal having various bandwidths between the wide frequency band audio signal and the narrow frequency band audio signal. The user's uncomfortable listening caused by a sudden change in energy during the switching process is avoided, and the user can receive a high-quality audio signal. To simplify the process of obtaining the processed first high frequency band signal, the first high frequency band signal and the second high frequency band signal of the frame of the previous M audio signals can be weighted directly. The weighting result is the processed first high frequency band signal.

  Step 202: Synthesize the processed first high frequency band signal and the first low frequency band signal of the frame of the current audio signal into a wide frequency band signal.

  Specifically, after the current audio signal frame is processed in step 201, the second high frequency band signal of the previous M audio signal frames is changed to the processed first high frequency band signal of the current frame. Then, in step 202, the processed first high frequency band signal and the first low frequency band signal of the frame of the current audio signal are combined into a wide frequency band signal so that the user can The received audio signal is always a wide frequency band audio signal. In this way, audio signals with various bandwidths are switched smoothly, which contributes to improving the quality of the audio signal received by the user.

  By using the method for switching audio signals in this embodiment, the first high frequency band signal of the frame of the current audio signal is processed according to the second high frequency band signal of the frame of the previous M audio signals. As a result, the second high frequency band signal of the frame of the previous M audio signals can be smoothly switched to the processed first high frequency band signal. In this way, during the process of switching between audio signals having various bandwidths, the high frequency band signals of such audio signals can be switched smoothly. Finally, the processed first high frequency band signal and first low frequency band signal are combined into a wide frequency band signal, and the wide frequency band signal is transmitted to the user terminal, so that the user enjoys a high quality audio signal. can do. By using the method for switching audio signals in this embodiment, it is possible to smoothly switch audio signals having various bandwidths, and thereby influence the sudden change of energy on the subjective audio quality of the audio signal. The quality of the audio signal received by the user can be improved. In addition, when audio signals having various bandwidths are not switched, the first high frequency band signal and the first low frequency band signal of the frame of the current audio signal are combined into a wide frequency band signal, The user can obtain a high quality audio signal.

  According to the above technical solution, optionally, as shown in FIG. 3, when switching from a wide frequency band audio signal to a narrow frequency band audio signal occurs, step 201 includes the following steps.

  Step 301: Predict fine structure information and envelope information corresponding to the first high frequency band signal.

Specifically, the audio signal can be divided into fine structure information and envelope information, and as a result, the audio signal can be restored according to the fine structure information and envelope information. In the process of switching from a wide frequency band audio signal to a narrow frequency band audio signal, only the low frequency band signal is available as the narrow frequency band audio signal, and the high frequency band signal is null, so the wide frequency band audio signal is narrowed. To enable smooth switching to a frequency band audio signal, the high frequency band signal required by the current narrow frequency band audio signal can be restored to enable smooth switching between the audio signals. There is a need. In step 301, predicted fine structure information and envelope information corresponding to the first high frequency band signal of the narrow frequency band audio signal are predicted.

  In order to more accurately predict the fine structure information and envelope information corresponding to the frame of the current audio signal, the first low frequency band signal of the frame of the current audio signal can be classified in step 301, and then the first Predicted fine structure information and envelope information corresponding to the high frequency band signal are predicted according to the signal type of the first low frequency band signal. For example, the narrow-band audio signal of the current frame can be a harmonic signal, a non-harmonic signal, or a transient signal. In this case, the fine structure information and envelope information corresponding to the type of the narrow frequency band audio signal can be acquired, and as a result, the fine structure information and envelope information corresponding to the high frequency band signal can be predicted more accurately. it can. The method for switching audio signals in this embodiment does not limit the signal type of the narrow frequency band audio signal.

  Step 302: Weighting the envelope information of the previous M frames corresponding to the predicted envelope information and the second high frequency band signal of the frame of the previous M audio signals, to support the first high frequency band signal Get first envelope information.

  Specifically, after the predicted fine structure information and envelope information corresponding to the first high frequency band signal of the current frame are predicted in step 301, the first envelope information corresponding to the first high frequency band signal is obtained. , According to the predicted envelope information and the envelope information of the previous M frames corresponding to the second high frequency band signal of the frame of the previous M speech signals.

  Specifically, the process of generating the first envelope information corresponding to the first high frequency band signal in step 302 can be performed using the following two methods.

  1. As shown in FIG. 4, the embodiment for obtaining the first envelope information in step 302 may include the following steps.

  Step 401: calculating a correlation coefficient between the first low frequency band signal and the low frequency band signal of the previous N audio signal frames, and calculating the correlation coefficient between the first low frequency band signal and the previous N audio signal frames; Calculate according to the low frequency band signal (N is 1 or more).

  Specifically, the first low frequency band signal of the current audio signal frame is compared with the low frequency band signal of the previous N audio signal frames, and the first low frequency band of the current audio signal frame is compared. A correlation coefficient between the signal and the low frequency band signal of the frame of the previous N speech signals is obtained. For example, the correlation between the first low frequency band signal of the frame of the current audio signal and the low frequency band signal of the frame of the previous N audio signals may be expressed in terms of energy scale or information type. Can be determined by determining the difference between the frequency band of the first low frequency band signal of the frame of the frame and the same frequency band of the low frequency band signal of the frame of the previous N speech signals, and thus the desired phase The number of relationships can be calculated. The previous frame of N audio signals may be a narrow frequency band audio signal, a wide frequency band audio signal, or a hybrid signal of a narrow frequency band audio signal and a wide frequency band audio signal.

  Step 402: Determine whether the correlation coefficient is within a given first threshold range.

  Specifically, after the correlation coefficient is calculated in step 401, it is determined whether or not the correlation coefficient is within a given threshold range. The purpose of calculating the correlation coefficient is whether the frame of the current speech signal is gradually switched from the previous N speech signal frames or suddenly switched from the previous N speech signal frames Is to judge. That is, the purpose is to determine whether their characteristics are the same and then to determine the weight of the high frequency band signal of the previous frame in the process of predicting the high frequency band signal of the current speech signal. is there. For example, if the first low frequency band signal of the frame of the current audio signal has the same energy as the low frequency band signal of the frame of the previous audio signal and these signal types are the same, The signal frame has a high correlation with the current audio signal frame. Therefore, in accurately restoring the first envelope information corresponding to the frame of the current audio signal, the envelope information or transient envelope information in the high frequency band corresponding to the previous frame of the audio signal occupies a greater weight. On the other hand, if there is a large difference in energy and signal type between the first low frequency band signal of the frame of the current voice signal and the low frequency band signal of the frame of the previous voice signal, It shows that the correlation between the signal and the frame of the current audio signal is low. Therefore, in accurately restoring the first envelope information corresponding to the frame of the current audio signal, the envelope information or transient envelope information of the high frequency band corresponding to the previous frame of the audio signal occupies a smaller weight.

  Step 403: If the correlation coefficient is not within the given first threshold range, the first envelope information is calculated by weighting according to the designated first weight 1 and the designated first weight 2. The first weight 1 indicates the weight value of the envelope information of the previous frame corresponding to the high frequency band signal of the frame of the previous audio signal, and the first weight 2 indicates the weight value of the envelope information.

  Specifically, if it is determined in step 402 that the correlation coefficient is not within a given first threshold range, it is determined that the current audio signal frame and the previous N audio signal frames It is shown that there is a slight correlation. Therefore, the envelope information or transient envelope information of the previous M frames corresponding to the first frequency band audio signal of the previous M frames, or the envelope information of the high frequency band corresponding to the frames of the previous audio signal, Slightly affects the first envelope information. When the first envelope information corresponding to the frame of the current audio signal is restored, the envelope information or transient envelope information of the previous M frames corresponding to the first frequency band audio signal of the previous M frames, or The envelope information in the high frequency band corresponding to the previous audio signal frame occupies a smaller weight. Therefore, the first envelope information of the current frame can be calculated according to the designated first weight 1 and first weight 2. The first weight 1 indicates the weight value of the envelope information corresponding to the high frequency band signal of the previous audio signal frame. The previous audio signal frame may be a wide frequency band audio signal or a processed narrow frequency band audio signal. In the case of the first switching, the frame of the previous audio signal is a wide frequency band audio signal, while the first weight 2 indicates the weight value of the predicted envelope information. The product of the predicted envelope information and the first weight 2 is added to the product of the envelope information of the previous frame and the first weight 1, and the weighted sum is the first envelope information of the current frame. The audio signal transmitted thereafter is processed according to this method and weight. The first envelope information corresponding to the audio signal is restored until the audio signal is switched again.

  Step 404: If the correlation coefficient is within the given first threshold range, the transient envelope information is calculated by weighting according to the designated second weight 1 and the designated second weight 2. The second weight 1 indicates the weight value of the envelope information before switching, and the second weight 2 indicates the weight value of the envelope information of the previous M frames (M is 1 or more).

  Specifically, if it is determined in step 402 that the correlation coefficient is within a given threshold range, the frame of the current audio signal is similar to the previous frame of N audio signals. The first envelope information having the characteristics and corresponding to the frame of the current audio signal is considerably influenced by the envelope information of the frame of the previous consecutive N audio signals. From the viewpoint of reliability with respect to the envelope of the previous M frames, it is necessary to calculate the transient envelope information corresponding to the frame of the current audio signal according to the envelope information of the previous M frames and the envelope information before switching. . When the first envelope information of the frame of the current audio signal is restored, the envelope information of the previous M frames and the envelope information of the previous L frames before switching occupy a larger weight. Then, first envelope information is calculated according to the transient envelope information. The second weight 1 indicates the weight value of the envelope information before switching, and the second weight 2 indicates the weight value of the envelope information of the previous M frames. In this case, the product of the envelope information before switching and the second weight 1 is added to the previous product of the envelope information of M frames and the second weight 2, and the weighted value becomes transient envelope information.

  Step 405: The second weight 1 is reduced by the first weight step, and the second weight 2 is enlarged by the first weight step.

  Specifically, when an audio signal is transmitted, the influence of the wide frequency band audio signal before switching on the subsequent narrow frequency band audio signal gradually decreases. In order to calculate the first envelope information more accurately, it is necessary to perform adaptive adjustment on the second weight 1 and the second weight 2. Since the influence of the wide frequency band audio signal of L frames before switching on the subsequent audio signal gradually decreases, the value of the second weight 1 gradually decreases, while the value of the second weight 2 gradually increases By increasing the value, the influence of the envelope information before switching on the first envelope information is weakened. In step 405, the second weight 1 and the second weight 2 can be corrected by the following equations. New second weight 1 = old second weight 1-first weight step; new second weight 2 = old second weight 2 + first weight step, where the first weight step is a specified value.

  Step 406: It is determined whether or not the designated third weight 1 is greater than the first weight 1.

  Specifically, the third weight 1 indicates the weight value of the transient envelope information. The effect of the transient envelope information on the first envelope information of the current frame can be determined by comparing the third weight 1 with the second weight 1. The transient envelope information is calculated according to the envelope information of the previous M frames and the envelope information before switching. Therefore, the third weight 1 actually represents the degree of influence that the first envelope information receives from the envelope information before switching.

  Step 407: If the third weight 1 is not larger than the first weight 1, weighting is performed according to the designated first weight 1 and first weight 2, and the first envelope information is calculated.

  Specifically, if it is determined in step 406 that the third weight 1 is less than or equal to the first weight 1, it means that the current audio signal frame is slightly far from the L audio signal frames before switching, And the first envelope information is mainly influenced by the envelope information of the previous M frames. Therefore, the first envelope information of the current frame can be calculated according to the designated first weight 1 and first weight 2.

  Step 408: When the third weight 1 is larger than the first weight 1, weighting is performed according to the designated third weight 1 and third weight 2, and the first envelope information is calculated. The third weight 1 indicates the weight value of the transient envelope information, and the third weight 2 indicates the weight value of the predicted envelope information.

  Specifically, if it is determined in step 406 that the third weight 1 is greater than the first weight 1, it means that the current audio signal frame is closer to the L audio signal frames before switching, and 1 Envelope information is greatly affected by the envelope information before switching. Therefore, it is necessary to calculate the first envelope information of the current frame according to the transient envelope information. The third weight 1 indicates the weight value of the transient envelope information, and the third weight 2 indicates the weight value of the predicted envelope information. In this case, the product of the transient envelope information and the third weight 1 is added to the product of the predicted envelope information and the third weight 2, and the weighted value becomes the first envelope information.

  Step 409: The third weight 1 is reduced by the second weight step, and the third weight 2 is enlarged by the second weight step until the third weight 1 becomes equal to 0.

  Specifically, the purpose of correcting the third weight 1 and the third weight 2 in step 409 is the same as the purpose of correcting the second weight 1 and the second weight 2 in step 405. That is, the purpose is to adaptively adjust the third weight 1 and the third weight 2 when the influence of the L audio signal frames before switching gradually decreases on the audio signal transmitted thereafter. To calculate the first envelope information more accurately. Since the influence of the L audio signal frames before switching on the subsequent audio signal gradually decreases, the value of the third weight 1 gradually decreases, while the value of the third weight 2 gradually increases As a result, the influence of the envelope information before switching on the first envelope information is weakened. In step 409, the third weight 1 and the third weight 2 can be corrected by the following equations. New third weight 1 = old third weight 1-second weight step; new third weight 2 = old third weight 2 + second weight step, where the second weight step is a designated value.

  The sum of the first weight 1 and the first weight 2 is equal to 1, the sum of the second weight 1 and the second weight 2 is equal to 1, and the sum of the third weight 1 and the third weight 2 is equal to 1. The initial value of the third weight 1 is larger than the initial value of the first weight 1, and the first weight 1 and the first weight 2 are constants. Specifically, weight 1 and weight 2 in this embodiment actually represent the percentage of envelope information before switching and envelope information of previous M frames in the first envelope information of the current frame. If the frame of the current audio signal is close to the L audio signal frames before switching and the correlation between them is high, the percentage of envelope information before switching is high, while the percentage of envelope information of the previous M frames Is low. If the frame of the current audio signal is a bit far from the L audio signal frames before switching, it indicates that the audio signal is being transmitted stably over the network, or If the frame is slightly correlated with the frame of the L audio signals before switching, it indicates that the characteristics of the frame of the current audio signal have already been changed. Thus, if the current audio signal frame is slightly affected by the L audio signal frames before switching, the percentage of envelope information before switching is low.

  Further, step 404 can be executed after step 405. That is, the second weight 1 and the second weight 2 can be corrected first, and then the transient envelope information is calculated according to the second weight 1 and the second weight 2. Similarly, step 408 can be performed after step 409. That is, the third weight 1 and the third weight 2 can be corrected first, and then the first envelope information is calculated according to the third weight 1 and the third weight 2.

  2. As shown in FIG. 5, another embodiment of obtaining the first envelope information according to step 302 may further include the following steps.

  Step 501: The correlation between the first low frequency band signal and the low frequency band signal of the frame of the previous audio signal is changed to the low frequency band signal of the first audio signal frame and the frame of the previous audio signal. Calculate according to the frequency band signal.

  Specifically, in order to obtain more accurate first envelope information, the frequency band of the first low frequency band signal of the current audio signal frame and the same frequency band of the low frequency band signal of the previous audio signal frame The relationship between is calculated. In this embodiment, “corr” may be used to indicate the correlation coefficient. This correlation coefficient is obtained from the energy relationship between the first low frequency band signal of the frame of the current audio signal and the low frequency band signal of the frame of the previous audio signal. “Corr” is large when the energy difference is small, and “corr” is small in the opposite case. For the specific process, refer to the calculation regarding the coefficient of the frame of the previous N audio signals in step 401.

  Step 502: Determine whether the correlation coefficient is within a given second threshold range.

  Specifically, after the value of “corr” is calculated in step 501, it is determined whether the calculated “corr” value is within a given second threshold. For example, the second threshold range may be represented by c1-c2 in this embodiment.

  Step 503: If the correlation coefficient is not within the given second threshold range, the first envelope information is calculated by weighting according to the designated first weight 1 and first weight 2. The first weight 1 indicates the weight value of the envelope information of the previous frame corresponding to the high frequency band signal of the frame of the previous audio signal, and the first weight 2 indicates the weight value of the predicted envelope information. The first weight 1 and the second weight 2 are constants.

  Specifically, when it is determined that the “corr” value is smaller than c1 or larger than c2, the first envelope information corresponding to the frame of the current audio signal is the envelope of the frame of the previous audio signal before switching. Judged to be slightly affected by information. Therefore, the first envelope information of the current frame is calculated according to the designated first weight 1 and first weight 2. The product of the predicted envelope information and the first weight 2 is added to the product of the envelope information of the previous frame and the first weight 1, and the weighted sum is the first envelope information of the current frame. The narrowband audio signal transmitted thereafter is processed according to this method and weight. The first envelope information corresponding to the narrowband audio signal is restored until the audio signal having various bandwidths is switched again. For example, the first weight 1 in this embodiment can be represented by a1, the first weight 2 can be represented by b1, the envelope information of the previous frame can be represented by pre_fenv, and the predicted envelope information is fenv. The first envelope information can be represented by cur_fenv. In this case, step 503 can be expressed by the following equation. cur_fenv = pre_fenv × a1 + fenv × b1

  Step 504: If the correlation coefficient is within the second threshold range, it is determined whether or not the designated second weight 1 is greater than the first weight 1. The second weight 1 indicates the weight value of the envelope information before switching corresponding to the high frequency band signal of the frame of the previous audio signal before switching.

  Specifically, in the case of c1 <corr <c2, the degree of influence of the envelope information before switching and the envelope information of the previous frame on the first envelope information of the current frame is determined by changing the second weight 1 to the first weight 1. Can be obtained by comparing with.

  Step 505: When the second weight 1 is not larger than the first weight 1, weighting is performed according to the designated first weight 1 and first weight 2, and the first envelope information is calculated.

  Specifically, if it is determined in step 504 that the second weight 1 is smaller than the first weight 1, it means that the current audio signal frame is a little far from the previous audio signal frame before switching, and 1 indicates that the envelope information is slightly affected by the envelope information of the previous frame before switching. Therefore, the first envelope information of the current frame can be calculated according to the designated first weight 1 and first weight 2. In this case, step 505 can be expressed by the following equation. cur_fenv = pre_fenv × a1 + fenv × b1

  Step 506: When the second weight 1 is larger than the first weight 1, weighting is performed according to the second weight 1 and the designated second weight 2, and the first envelope information is calculated. The second weight 2 indicates the weight value of the predicted envelope information. For example, the second weight 1 can be represented by a2, and the second weight 2 can be represented by b2.

  Specifically, if it is determined in step 504 that the second weight 1 is greater than the first weight 1, it means that the frame of the current audio signal is closer to the first frequency band audio signal of the previous frame before switching. , And that the first envelope information is greatly influenced by the envelope information before switching corresponding to the frame of the previous audio signal before switching. Accordingly, the first envelope information of the current frame is calculated according to the designated second weight 1 and second weight 2. In this case, the product of the predicted envelope information and the second weight 2 is added to the product of the envelope information before switching and the second weight 1, and the weighted sum becomes the first envelope information of the current frame. The envelope information before switching can be represented by con_fenv. In this case, step 506 can be represented by the following equation: cur_fenv = con_fenv × a2 + fenv × b2

  Step 507: The second weight 1 is reduced by the second weight step, and the second weight 2 is enlarged by the second weight step.

  Specifically, when an audio signal is transmitted, the influence of the audio signal before switching on the frame of the subsequent audio signal gradually decreases. In order to calculate the first envelope information more accurately, it is necessary to perform adaptive adjustment on the second weight 1 and the second weight 2. The influence of the audio signal before switching on the frame of the subsequent audio signal gradually decreases, while the influence of the frame of the previous audio signal close to the frame of the current audio signal gradually increases. Therefore, the value of the second weight 1 is gradually decreased, while the value of the second weight 2 is gradually increased. In this way, the influence of the envelope information before switching on the first envelope information is weakened, while the influence of the predicted envelope information on the first envelope information is strengthened. In step 507, the second weight 1 and the second weight 2 can be corrected by the following equations. New second weight 1 = old second weight 1-first weight step; new second weight 2 = old second weight 2 + first weight step, where the first weight step is a specified value.

  The sum of the first weight 1 and the first weight 2 is equal to 1, the sum of the second weight 1 and the second weight 2 is equal to 1, and the initial value of the second weight 1 is greater than the initial value of the first weight 1. large.

  Step 303: Generate a processed first high frequency band signal according to the first envelope information and the predicted fine structure information.

  Specifically, after the first envelope information of the current frame is acquired in step 302, the processed first high frequency band signal can be generated according to the first envelope information and the predicted fine structure information, and as a result The second high frequency band signal can be smoothly switched to the processed first high frequency band signal.

  In the process of switching the audio signal from the wide frequency band audio signal to the narrow frequency band audio signal by using the method for switching the audio signal in this embodiment, the processed first high frequency band signal of the current frame is: Obtained according to the predicted microstructure information and the first envelope information. In this way, the second high frequency band signal of the wide frequency band audio signal before switching can be smoothly switched to the processed first high frequency band signal corresponding to the narrow frequency band audio signal. Can improve the quality of the audio signal received.

  Based on the foregoing technical solution, step 202 shown in FIG. 6 includes the following steps.

  Step 601: It is determined whether the processed first high frequency band signal needs to be attenuated according to the frame of the current audio signal and the frame of the previous audio signal before switching.

  Specifically, the first high frequency band signal of the narrowband audio signal is null. In the process of switching a wide frequency band audio signal to a narrow frequency band audio signal, the energy of the processed first high frequency band signal to prevent the negative effects of the processed first high frequency band signal corresponding to the restored narrow frequency band audio signal Is attenuated frame by frame until the attenuation coefficient reaches a given threshold after the number of wide frequency band signals expanded from the narrow frequency band audio signal reaches a given number of frames. The interval between the frame of the current audio signal and the audio signal of the frame before switching can be acquired according to the frame of the current audio signal and the audio signal of the frame before switching. For example, the number of frames of the narrow frequency band audio signal can be recorded using a counter, and the number of frames in this case can be a predetermined value of 0 or more.

  Step 602: If the processed first high frequency band signal does not need to be attenuated, combine the processed first high frequency band signal and the first low frequency band signal into a wide frequency band signal.

  Specifically, if it is determined in step 601 that the processed first high frequency band signal does not need to be attenuated, the processed first high frequency band signal and the first low frequency band signal are directly converted to the wide frequency band signal. Synthesized.

  Step 603: If the processed first high frequency band signal needs to be attenuated, it is determined whether or not the attenuation coefficient corresponding to the processed first high frequency band signal is greater than a threshold value.

  Specifically, the initial value of the attenuation coefficient is 1, and the threshold value is 0 or more and less than 1. If it is determined in step 601 that the processed first high frequency band signal needs to be attenuated, in step 603, is the attenuation coefficient corresponding to the processed first high frequency band signal greater than a given threshold? It is determined whether or not.

  Step 604: If the attenuation factor is not greater than the given threshold, multiply the processed first high frequency band signal by the threshold to synthesize the product and the first low frequency band signal into a wide frequency band signal.

  Specifically, if step 603 determines that the attenuation factor is not greater than a given threshold, it means that the energy of the processed first high frequency band signal has already been attenuated to some extent and has been processed It shows that the first high frequency band signal may not have an adverse effect. In this case, this attenuation rate can be maintained. The processed first high frequency band signal is then multiplied by a threshold, and then the product and the first low frequency band signal are combined into a wide frequency band signal.

  Step 605: If the attenuation factor is greater than a given threshold, multiply the processed first high frequency band signal by the attenuation factor to synthesize the product and the first low frequency band signal into a wide frequency band signal.

  Specifically, if the attenuation factor is greater than a given threshold in step 603, it is possible that the processed first high frequency band signal may result in uncomfortable listening at the attenuation factor. This indicates that further attenuation is required until the threshold is reached. The processed first high frequency band signal is then multiplied by an attenuation factor, and then the product and the first low frequency band signal are combined into a wide frequency band signal.

  Step 606: Modify the attenuation coefficient to reduce the attenuation coefficient.

  Specifically, when an audio signal is transmitted, the influence of the audio signal before switching on the subsequent narrowband audio signal is gradually reduced, and the attenuation coefficient is also gradually reduced.

  Optionally, based on the above technical solution, the embodiment of obtaining the processed first high frequency band signal by step 201 when switching from the narrow frequency band audio signal to the wide frequency band audio signal is illustrated in FIG. The following steps are included as shown in FIG.

  Step 701: Weighting is performed according to designated fourth weight 1 and fourth weight 2, and a processed first high frequency band signal is calculated. The fourth weight 1 indicates the weight value of the second high frequency band signal, and the fourth weight 2 indicates the weight value of the first high frequency band signal of the frame of the current audio signal.

  Specifically, in the process of switching the narrow frequency band audio signal to the wide frequency band audio signal, the high frequency band signal of the wide frequency band audio signal is not null, and the high frequency band signal corresponding to the narrow frequency band audio signal is null. Therefore, it is necessary to make it possible to smoothly switch the narrow frequency band audio signal to the wide frequency band audio signal by attenuating the energy of the high frequency band signal of the wide frequency band audio signal. The product of the second high frequency band signal and the fourth weight 1 is added to the product of the first high frequency band signal and the fourth weight 2, and the weighted value becomes the processed first high frequency band signal.

  Step 702: The fourth weight 1 is reduced by the third weight step, and the fourth weight 2 is enlarged by the third weight step until the fourth weight 1 becomes equal to 0. The sum of the fourth weight 1 and the fourth weight 2 is equal to 1.

  Specifically, when an audio signal is transmitted, the influence of the narrow frequency band audio signal before switching on the subsequent wide frequency band audio signal is gradually reduced. Accordingly, the fourth weight 1 gradually decreases, while the fourth weight 2 gradually increases until the fourth weight 1 is equal to 0 and the fourth weight 2 is equal to 1. That is, the transmitted audio signal is always a wide frequency band audio signal.

  Similarly, as shown in FIG. 8, another embodiment for obtaining the processed first high frequency band signal according to step 201 may further include the following steps.

  Step 801: Weighting is performed according to designated fifth weight 1 and fifth weight 2, and a processed first high frequency band signal is calculated. The fifth weight 1 is the weight value of the designated fixed parameter, and the fifth weight 2 is the weight value of the first high frequency band signal of the current audio signal frame.

  Specifically, since the first high frequency band signal of the narrow frequency band audio signal is null, the fixed parameter can be set to exchange the high frequency band signal of the narrow frequency band audio signal, where the fixed parameter is 0 Thus, the constant is smaller than the energy of the first high frequency band signal. The product of the fixed parameter and the fifth weight 1 is added to the product of the first high frequency band signal and the fifth weight 2, and the weighted value becomes the processed first high frequency band signal.

  Step 802: The fifth weight 1 is reduced by the fourth weight step, and the fifth weight 2 is enlarged by the fourth weight step until the fifth weight 1 becomes equal to 0. The sum of the fifth weight 1 and the fifth weight 2 is equal to 1.

  Specifically, when an audio signal is transmitted, the influence of the narrow frequency band audio signal before switching on the subsequent wide frequency band audio signal is gradually reduced. Accordingly, the fifth weight 1 gradually decreases, while the fifth weight 2 gradually increases until the fifth weight 1 is equal to 0 and the fifth weight 2 is equal to 1. That is, the transmitted audio signal is always a true wide frequency band audio signal.

  By using the method for switching audio signals in this embodiment, in the process of switching the audio signal from the narrow frequency band audio signal to the wide frequency band audio signal, the high frequency band signal of the wide frequency band audio signal is attenuated. Obtain a processed high frequency band signal. In this way, the high frequency band signal corresponding to the narrow frequency band audio signal before switching can be smoothly switched to the processed high frequency band signal corresponding to the wide frequency band audio signal, and thus the audio received by the user. This can contribute to signal quality improvement.

  In this embodiment, the envelope information can also be exchanged by other parameters that can represent high frequency band signals, such as linear predictive coding (LPC) parameters or amplitude parameters.

  One skilled in the art can appreciate that all or part of the steps of the method according to embodiments of the present invention can be implemented by a program that instructs the associated hardware. The program can be stored in a computer readable storage medium. When the program runs, the steps of the method according to embodiments of the invention are performed. The storage medium may be read only memory (ROM), random access memory (RAM), magnetic disk or compact disk read only memory (CD-ROM).

  FIG. 9 shows the structure of the first embodiment of an apparatus for switching audio signals. As shown in FIG. 9, the apparatus for switching audio signals includes a processing module 91 and a first synthesis module 92.

  The processing module 91 weights and processes the first high frequency band signal of the current audio signal frame and the second high frequency band signal of the previous M audio signal frames when the audio switch occurs. Adapted to obtain a finished first high frequency band signal. M is 1 or more.

  The first synthesis module 92 is adapted to synthesize the processed first high frequency band signal and the first low frequency band signal of the frame of the current audio signal into a wide frequency band signal.

  In the apparatus for switching audio signals in this embodiment, a processing module processes a first high frequency band signal of a frame of a current audio signal according to a second high frequency band signal of a frame of previous M audio signals. As a result, the second high frequency band signal can be smoothly switched to the processed first high frequency band signal. In this way, during the process of switching between audio signals having various bandwidths, the high frequency band signals of such audio signals can be switched smoothly. Finally, the first combining module combines the processed first high frequency band signal and the first low frequency band signal into a wide frequency band signal, and the wide frequency band signal is transmitted to the user terminal, so that the user can Quality audio signals can be enjoyed. By using the method for switching audio signals in this embodiment, it is possible to smoothly switch audio signals having various bandwidths, and thereby influence the sudden change of energy on the subjective audio quality of the audio signal. The quality of the audio signal received by the user can be improved.

  FIG. 10 shows the structure of a second embodiment of the device for switching audio signals. As shown in FIG. 10, the apparatus for switching audio signals in this embodiment further includes a second synthesis module 103 based on the first embodiment.

  The second synthesis module 103 is adapted to synthesize the first high frequency band signal and the first low frequency band signal into a wide frequency band signal when no switching of the audio signal occurs.

  In the apparatus for switching audio signals in this embodiment, the second synthesis module is configured to switch the first low frequency of the first frequency band audio signal of the current frame when switching between audio signals having various bandwidths occurs. The band signal and the first high frequency band signal are set to be combined with the wide frequency band signal. In this way, the quality of the audio signal received by the user is improved.

According to the above technical solutions, optionally, as shown in FIGS. 10 and 11, when switching from a wide frequency band audio signal to a narrow frequency band audio signal occurs, the processing module 101 Including.
A prediction module 1011 adapted to predict fine structure information and envelope information corresponding to the first high frequency band signal;
The first corresponding to the first high frequency band signal by weighting the envelope information of the previous M frames corresponding to the predicted high envelope signal and the second high frequency band signal of the frame of the previous M audio signals. A first generation module 1012 adapted to obtain envelope information, and a second generation module 1013 adapted to generate a processed first high frequency band signal according to the first envelope information and the predicted fine structure information .

  Furthermore, the apparatus for switching audio signals in this embodiment can include a classification module 1010 adapted to classify the first low frequency band signal of the frame of the current audio signal. The prediction module 1011 is further adapted to predict fine structure information and envelope information corresponding to the first low frequency band signal of the frame of the current speech signal.

  In the apparatus for switching audio signals in this embodiment, the prediction module predicts the fine structure information and envelope information corresponding to the first high frequency band signal, and as a result, the processed first high frequency band signal is the first It can be generated accurately by the generation module and the second generation module. In this way, the first high frequency band signal can be smoothly switched to the processed first high frequency band signal, thereby improving the quality of the audio signal received by the user. Further, the classification module classifies the first low frequency band signal of the frame of the current speech signal, and the prediction module obtains predicted fine structure information and predicted envelope information according to the signal type. In this way, the predicted fine structure information and the predicted envelope information become more accurate, thereby improving the quality of the audio signal received by the user.

Based on the foregoing technical solutions, and optionally, as shown in FIGS. 10 and 12, the first synthesis module 102 includes the following modules:
A first determination module 1021 adapted to determine whether the processed first high frequency band signal needs to be attenuated according to the frame of the current audio signal and the frame of the previous audio signal before switching,
Synthesize the processed first high frequency band signal and the first low frequency band signal into a wide frequency band signal when the first determination module 1021 determines that the processed first high frequency band signal does not need to be attenuated 3rd synthesis module 1022, adapted to
Whether the attenuation factor corresponding to the processed first high frequency band signal is greater than a given threshold when the first determination module 1021 determines that the processed first high frequency band signal needs to be attenuated A second decision module 1023, adapted to determine whether
If the second decision module 1023 determines that the attenuation factor is not greater than a given threshold, the processed first high frequency band signal is multiplied by the threshold to multiply the product and the first low frequency band signal to the wide frequency band A fourth synthesis module 1024, adapted to synthesize to the signal
If the second decision module 1023 determines that the attenuation factor is greater than a given threshold, the processed first high frequency band signal is multiplied by the attenuation factor to multiply the product and first low frequency band signal to the wide frequency band signal. A fifth synthesis module 1025 adapted to synthesize, and a first modification module 1026 adapted to modify the attenuation coefficient to reduce the attenuation coefficient.

  The initial value of the attenuation coefficient is 1, and the threshold value is 0 or more and less than 1.

  By using a device for switching audio signals, the processed first high frequency band signal is attenuated, resulting in a more accurate wide frequency band signal obtained by processing the frame of the current audio signal, As a result, the quality of the audio signal received by the user is improved.

According to the above technical solution, optionally, when switching from a narrow frequency band audio signal to a wide frequency band audio signal occurs, as shown in FIGS. 10 and 13a, the processing module 101 in this embodiment Includes the following modules:
Adapted to calculate the processed first high frequency band signal weighted according to the specified fourth weight 1 and fourth weight 2, where the fourth weight 1 refers to the weight value of the second high frequency band signal, 4 weight 2 indicates the weight value of the first high frequency band signal, the 4th weight 1 is reduced by the 1st calculation module 1011a and the 3rd weight step, and the 3rd weight step until the 4th weight 1 becomes equal to 0 The second correction module 1012a is adapted to enlarge the fourth weight 2 by the sum, and the sum of the fourth weight 1 and the fourth weight 2 is equal to 1.

Similarly, as shown in FIGS. 10 and 13b, when switching from a narrow frequency band audio signal to a wide frequency band audio signal occurs, the processing module 101 in this embodiment may further include the following modules.
Adapted to calculate the processed first high frequency band signal weighted according to the specified fifth weight 1 and fifth weight 2, where the fifth weight 1 refers to the weight value of the specified fixed parameter and the fifth weight 2 indicates the weight value of the first high frequency band signal.The second weight is reduced by the second calculation module 1011b and the fourth weight step by the fourth weight step until the fifth weight 1 becomes equal to 0. It is adapted to expand 5 weight 2, the sum of 5th weight 1 and 5th weight 2 is equal to 1, the fixed parameter is 0 or more, and it is a constant smaller than the energy value of the 1st high frequency band signal There is a third modification module 1012b.

  By using the apparatus for switching the audio signal in this embodiment, in the process of switching the audio signal from the narrow frequency band audio signal to the wide frequency band audio signal, the high frequency band signal of the wide frequency band audio signal is attenuated. Obtain a processed high frequency band signal. In this way, the high frequency band signal corresponding to the narrow frequency band audio signal before switching can be smoothly switched to the processed high frequency band signal corresponding to the wide frequency band audio signal, and thus the audio received by the user. This can contribute to signal quality improvement.

  It should be noted that the above embodiments have been presented only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. While the invention has been described in detail with reference to the above embodiments, it will be apparent to those skilled in the art that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention. The present invention is intended to cover modifications and variations as long as they are within the scope of protection as defined in the following claims or their equivalents.

91 Processing module
92 1st synthesis module
103 2nd synthesis module
101 processing module
102 1st synthesis module
1010 Classification module
1011 prediction module
1012 First generation module
1013 Second generation module
1021 First decision module
1022 3rd synthesis module
1023 Second decision module
1024 Fourth judgment module
1025 5th synthesis module
1026 First modification module
1011a First calculation module
1012a Second modification module
1011b Second calculation module
1012b Third modification module

Claims (16)

A method for switching audio signals,
When switching of the audio signal from the wide frequency band to the narrow frequency band or from the narrow frequency band to the wide frequency band occurs, the first high frequency band signal of the frame of the audio signal after the switching and the previous one or more Weighting a second high frequency band signal of a frame of M audio signals to obtain a processed first high frequency band signal;
Synthesizing the processed first high frequency band signal and the first low frequency band signal of the frame of the audio signal into a wide frequency band signal. When switching from a wide frequency band audio signal to a narrow frequency band audio signal occurs, the first high frequency band signal of the frame of the audio signal after the switching and the first of the frames of the M previous audio signals are switched. The step of weighting a high frequency band signal to obtain the processed first high frequency band signal,
Predicting fine structure information and envelope information corresponding to the first high frequency band signal of the frame of the current audio signal;
Weighting the predicted envelope information and the previous M frame envelope information corresponding to the second high frequency band signal of the previous M speech signal frames to the first high frequency band signal Obtaining corresponding first envelope information;
And generating the processed first high frequency band signal according to the first envelope information and the predicted microstructure information. Predicting the fine structure information and envelope information corresponding to the first high frequency band signal of the frame of the audio signal;
Classifying the first low frequency band signal of the frame of the audio signal;
And predicting the fine structure information and envelope information according to a signal type of the first low frequency band signal. Weighting the predicted envelope information and the envelope information of the previous M frames corresponding to the second high frequency band signal of the frame of the previous M speech signals to weight the first high frequency band signal The step of obtaining the first envelope information corresponding to:
A correlation coefficient between the first low frequency band signal and a low frequency band signal of a frame of N speech signals that is one or more of the previous low frequency band signal and the previous N speeches. Calculating according to the low frequency band signal of a frame of signal; determining whether the correlation coefficient is within a given first threshold range;
When the correlation coefficient is not within the first threshold range, weighting according to a designated first weight 1 and a designated first weight 2, and calculating the first envelope information, A first weight 1 indicates a weight value of envelope information of a previous frame corresponding to a high frequency band signal of a frame of a previous audio signal, and the first weight 2 indicates a weight value of the envelope information; and
When the correlation coefficient is within the first threshold range, weighting is performed according to a designated second weight 1 and a designated second weight 2, and calculating transient envelope information, Weight 1 indicates a weight value of envelope information corresponding to a high frequency band signal of L audio signal frames which is 1 or more before switching, and the second weight 2 is envelope information of the previous M frames Pointing to the weight value of
Reducing the second weight 1 by a first weight step and expanding the second weight 2 by the first weight step;
Determining whether a designated third weight 1 is greater than the first weight 1;
When the third weight 1 is not greater than the first weight 1, weighting according to the designated first weight 1 and the first weight 2, and calculating the first envelope information;
When the third weight 1 is larger than the first weight 1, the step of calculating the first envelope information by weighting according to the designated third weight 1 and the third weight 2, Weight 1 refers to a weight value of the transient envelope information, and the third weight 2 refers to a weight value of the predicted envelope information; and
Reducing the third weight 1 by a second weight step, and enlarging the third weight 2 by the second weight step until the third weight 1 becomes equal to 0,
The sum of the first weight 1 and the first weight 2 is equal to 1, the sum of the second weight 1 and the second weight 2 is equal to 1, and the third weight 1 and the third weight 2 The sum of the two is equal to 1, the initial value of the third weight 1 is larger than the initial value of the first weight 1, and the first weight 1 and the first weight 2 are constants. the method of. Weighting the predicted envelope information and the envelope information of the previous M frames corresponding to the second high frequency band signal of the frame of the previous M speech signals to weight the first high frequency band signal The step of obtaining the first envelope information corresponding to:
A correlation coefficient between the first low frequency band signal of the frame and the low frequency band signal of the frame of the previous audio signal, the correlation coefficient between the first low frequency band signal of the frame and the frame of the previous audio signal; Calculating according to the low frequency band signal;
Determining whether the correlation coefficient is within a given second threshold range;
When the correlation coefficient is not within the second threshold range, weighting according to a designated first weight 1 and a designated first weight 2, and calculating the first envelope information, The first weight 1 refers to the weight value of the envelope information of the previous frame corresponding to the high frequency band signal of the frame of the previous audio signal, the first weight 2 refers to the weight value of the predicted envelope information, The first weight 1 and the first weight 2 are constants; and
When the correlation coefficient is within the second threshold range, it is a step of determining whether a designated second weight 1 is greater than the first weight 1, wherein the second weight 1 is Indicating a weight value of envelope information corresponding to the high frequency band signal of the frame of the previous audio signal before switching;
If the second weight 1 is not greater than the first weight 1, weighting according to the designated first weight 1 and the first weight 2, and calculating the first envelope information;
When the second weight 1 is larger than the first weight 1, the step of calculating the first envelope information by weighting according to the second weight 1 and the designated second weight 2, the second weight 2 Refers to the weight value of the predicted envelope information, and
Reducing the second weight 1 by a second weight step and enlarging the second weight 2 by the second weight step,
The sum of the first weight 1 and the first weight 2 is equal to 1, the sum of the second weight 1 and the second weight 2 is equal to 1, and the initial value of the second weight 1 is the first value. The method according to claim 2, wherein the method is larger than an initial value of weight 1. The step of synthesizing the first low frequency band signal of the processed first high frequency band signal and the frame of the audio signal into the wide frequency band signal,
Determining whether the processed first high frequency band signal needs to be attenuated according to the frame of the audio signal and the frame of the previous audio signal before the switching;
If attenuation is not required, combining the processed first high frequency band signal and the first low frequency band signal into the wide frequency band signal;
If attenuation is required, determining whether an attenuation coefficient corresponding to the first high frequency band signal is greater than a given threshold;
If the attenuation factor is not greater than the given threshold, the processed first high frequency band signal is multiplied by the threshold, and the processed first high frequency band signal and the threshold Combining the product and the first low frequency band signal into the wide frequency band signal;
When the attenuation factor is greater than the given threshold, the processed first high frequency band signal is multiplied by the attenuation factor, the product of the processed first high frequency band signal and the attenuation factor, and the Synthesizing a first low frequency band signal into the wide frequency band signal;
Modifying the attenuation coefficient to reduce the attenuation coefficient;
6. The method according to claim 1, wherein an initial value of the attenuation coefficient is 1, and the threshold value is 0 or more and less than 1. When switching from a narrow frequency band audio signal to a wide frequency band audio signal occurs, the first high frequency band signal of the frame of the audio signal and the second high frequency band of the frame of the previous M audio signals The step of weighting a signal to obtain the processed first high frequency band signal;
Calculating the processed first high frequency band signal by weighting according to a designated fourth weight 1 and a designated fourth weight 2, wherein the fourth weight 1 is a weight of the second high frequency band signal The fourth weight 2 indicates a weight value of the first high frequency band signal, and
Reducing the fourth weight 1 by a third weight step, and enlarging the fourth weight 2 by the third weight step until the fourth weight 1 becomes equal to 0, The method according to claim 1, further comprising: a step in which a sum with the fourth weight 2 is equal to 1. When switching from a wide frequency band audio signal to a narrow frequency band audio signal occurs, the first high frequency band signal of the frame of the audio signal and the second high frequency band of the frame of the previous M audio signals The step of weighting a signal to obtain the processed first high frequency band signal;
Calculating the processed first high frequency band signal by weighting according to a designated fifth weight 1 and a designated fifth weight 2, wherein the fifth weight 1 indicates a weight value of a designated fixed parameter. The fifth weight 2 refers to a weight value of the first high frequency band signal; and
Reducing the fifth weight 1 by a fourth weight step and enlarging the fifth weight 2 by the fourth weight step until the fifth weight 1 is equal to 0, The sum of the fifth weight 2 is equal to 1, and
7. The method according to claim 1, wherein the fixed parameter is a constant that is equal to or greater than 0 and smaller than an energy value of the first high frequency band signal. 9. The method according to claim 1, further comprising a step of synthesizing the first high frequency band signal and the first low frequency band signal into the wide frequency band signal when the switching of the audio signal has not occurred. The method according to item. An apparatus for switching audio signals,
When switching of the audio signal from the wide frequency band to the narrow frequency band or from the narrow frequency band to the wide frequency band occurs, the first high frequency band signal of the frame of the audio signal after the switching and the previous one or more A processing module adapted to weight a second high frequency band signal of a frame of M audio signals to obtain a processed first high frequency band signal;
And a first synthesis module adapted to synthesize the processed first high frequency band signal and the first low frequency band signal of the frame of the audio signal into a wide frequency band signal. When the switching from a wide frequency band audio signal to a narrow frequency band occurs, the processing module is adapted to predict fine structure information and envelope information corresponding to the first high frequency band signal of the frame of the audio signal Predicted module,
Weighting the predicted envelope information and the previous M frame envelope information corresponding to the second high frequency band signal of the previous M speech signal frames to the first high frequency band signal A first generation module adapted to obtain corresponding first envelope information;
11. The apparatus of claim 10, comprising: a second generation module adapted to generate the processed first high frequency band signal according to the first envelope information and the predicted microstructure information. A classification module adapted to classify the first low frequency band signal of the frame of the audio signal;
The prediction module is further adapted to predict the microstructure information and the envelope information according to a signal type of the first low frequency band signal;
The apparatus according to claim 11. The first synthesis module is
A first determination module adapted to determine whether the processed first high frequency band signal needs to be attenuated according to the frame of the audio signal and the frame of the previous audio signal before switching;
When the first determination module determines that the processed first high frequency band signal does not need to be attenuated, the processed first high frequency band signal and the first low frequency band signal are converted to the wide frequency band signal. A third synthesis module adapted to synthesize,
When the first determination module determines that the processed first high frequency band signal needs to be attenuated, an attenuation coefficient corresponding to the processed first high frequency band signal is greater than a given threshold value A second decision module adapted to determine whether or not,
If the second determination module determines that the attenuation coefficient is not greater than the given threshold, the processed first high frequency band signal is multiplied by the threshold to produce a product and the first low frequency A fourth synthesis module adapted to synthesize a band signal into the wide frequency band signal;
If the second determination module determines that the attenuation coefficient is greater than the given threshold, the processed first high frequency band signal is multiplied by the attenuation coefficient to yield a product and the first low frequency band signal A fifth synthesis module adapted to synthesize the signal into the wide frequency band signal;
A first modification module adapted to modify the damping factor to reduce the damping factor;
The apparatus according to any one of claims 10 to 12, wherein an initial value of the attenuation coefficient is 1, and the threshold value is 0 or more and less than 1. When the switching from the narrow frequency band audio signal to the wide frequency band audio signal occurs, the processing module weights according to the designated fourth weight 1 and the designated fourth weight 2, and the processed first high frequency band Adapted to calculate a signal, wherein the fourth weight 1 refers to a weight value of the second high frequency band signal, and the fourth weight 2 refers to a weight value of the first high frequency band signal Modules,
Adapted to reduce the fourth weight 1 by a third weight step and to enlarge the fourth weight 2 by the third weight step until the fourth weight 1 is equal to 0; 14. The apparatus according to any one of claims 10 to 13, further comprising: a second correction module that is equal to 1 with the fourth weight 2. When switching from a narrow frequency band audio signal to a wide frequency band audio signal occurs, the processing module
Adapted to calculate the processed first high frequency band signal weighted according to a designated fifth weight 1 and designated fifth weight 2, wherein the fifth weight 1 refers to a weight value of a designated fixed parameter. The fifth weight 2 indicates a weight value of the first high frequency band signal; a second calculation module;
Adapted to reduce the fifth weight 1 by a fourth weight step and to enlarge the fifth weight 2 by the fourth weight step until the fifth weight 1 is equal to 0; The third correction module includes a third correction module, wherein a sum of the fifth weight 2 is equal to 1, and the fixed parameter is equal to or greater than 0 and is a constant smaller than an energy value of the first high frequency band signal. 14. The device according to any one of 1 to 13. Further comprising a second synthesis module adapted to synthesize the first high frequency band signal and the first low frequency band signal into the wide frequency band signal when switching of the audio signal has not occurred. Item 16. The device according to any one of Items 10 to 15.

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