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    • 专利摘要:
    BANDWIDTH EXTENSION METHOD AND APPLIANCE. The present invention relates to a method and apparatus for extending bandwidth. The bandwidth extension method includes: acquiring a bandwidth extension parameter, where the bandwidth extension parameter includes one or more of the following parameters: a linear LPC prediction coefficient, a spectral frequency parameter in LSF online, an interval period, a decoding rate, an adaptive codebook contribution and an algebraic codebook contribution; and performing, according to the bandwidth extension parameter, the bandwidth extension on a low frequency decoded signal, to obtain a high frequency signal. In the embodiments of the present invention, the bandwidth extension is performed, using the bandwidth extension parameter and a correction factor obtained through calculation using the bandwidth extension parameter in the decoded signal. low frequency, thereby recovering the high frequency signal. The high frequency signal recovered using the method (...).
    公开号:BR112016005850B1
    申请号:R112016005850-0
    申请日:2014-04-15
    公开日:2020-12-08
    发明作者:Zexin LIU；Lei Miao；Bin Wang
    申请人:Huawei Technologies Co., Ltd；
    IPC主号:
    专利说明:

    TECHNICAL FIELD
    [1] The present invention relates to the field of audio encoding and decoding and, in particular, to a method and apparatus for extending bandwidth in a linear prediction excited by algebraic code (ACELP) of a broadband of medium and low rate. BACKGROUND OF THE INVENTION
    [2] A blind bandwidth extension technology is a technology in a decoder, in which a decoder extends the blind bandwidth according to a low frequency decoding signal and using a decoding method. corresponding forecast.
    [3] During encoding and decoding by ACELP of a medium and low rate broadband, all existing algorithms first reduce the resolution of a sampled broadband signal at 16 kHz to 12.8 kHz, and then perform encoding . Thus, the bandwidth of a signal output after encoding and decoding is only 6.4 kHz. If an original algorithm is not changed, the information in a part with a bandwidth of 6.4 to 8 kHz or from 6.4 to 7 kHz needs to be retrieved in a blind bandwidth extension mode, that is, the corresponding recovery is performed only at the decoder.
    [4] However, a high frequency band signal retrieved by existing blind bandwidth extension technology deviates too far from an original high frequency band signal, which causes the recovered high frequency band signal to be unsatisfactory. SUMMARY
    [5] The present invention provides a method and a bandwidth extension apparatus, and aims to solve the problem of a recovered high frequency band signal using an existing blind bandwidth extension technology. of an original high-frequency band signal.
    [6] According to a first aspect, a bandwidth extension method is provided, including: acquiring a bandwidth extension parameter, where the bandwidth extension parameter includes one or more of the following parameters : a linear prediction coefficient (LPC), an in-line spectral frequency parameter (LSF), an interval period, a decoding rate, an adaptive codebook contribution and an algebraic codebook contribution; and performing, according to the bandwidth extension parameter, the bandwidth extension on a low frequency decoded signal, to obtain a high frequency band signal.
    [7] With reference to the first aspect, in a first way of implementing the first aspect, the realization, according to the bandwidth extension parameter, of bandwidth extension in a low frequency decoded signal, to obtain a high frequency band signal includes: predicting high frequency energy and a high band excitation signal according to the bandwidth extension parameter; and obtaining the high frequency band signal according to the high frequency energy and the high band excitation signal.
    [8] With reference to the first way of implementing the first aspect, in a second way of implementing the first aspect, the high frequency energy includes a high frequency gain; and the prediction of high frequency energy and a high band excitation signal according to the bandwidth extension parameter includes: predicting the high frequency gain according to the LPC; and adaptively predict the high band excitation signal according to the LSF parameter, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [9] With reference to the second mode of implementation of the first aspect, in a third mode of implementation of the first aspect, the adaptive prediction of the high band excitation signal according to the LSF parameter, the contribution of the codebook adaptive and the contribution of the algebraic code book includes: adaptively predicting the high band excitation signal according to the decoding rate, the LSF parameter, the contribution of the adaptive code book and the contribution of the algebraic code book .
    [10] With reference to the first way of implementing the first aspect, in a fourth way of implementing the first aspect, high frequency energy includes a high frequency gain; and the prediction of high frequency energy and a high band excitation signal according to the bandwidth extension parameter includes: predicting the high frequency gain according to the LPC; and adaptively predicting the high band excitation signal according to the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [11] With reference to the fourth mode of implementation of the first aspect, in a fifth mode of implementation of the first aspect, the adaptive prediction of the high band excitation signal according to the contribution of the adaptive codebook and the contribution of the algebraic code book includes: adaptively predicting the high band excitation signal according to the decoding rate, the contribution of the adaptive code book and the contribution of the algebraic code book.
    [12] With reference to the first way of implementing the first aspect, in a sixth way of implementing the first aspect, the high frequency energy includes a high frequency envelope; and the prediction of high frequency energy and a high band excitation signal according to the bandwidth extension parameter includes: predicting the high frequency envelope according to the decoded low frequency signal or an excitation signal of low frequency, where the low frequency excitation signal is the sum of the contribution of the adaptive codebook and the contribution of the algebraic codebook; and predicting the high band excitation signal according to the low frequency decoded signal or the low frequency excitation signal.
    [13] With reference to the sixth mode of implementation of the first aspect, in a seventh mode of implementation of the first aspect, the prediction of the high-band excitation signal according to the low-frequency decoded signal or the low-frequency excitation signal includes: predicting the high band excitation signal according to the decoding rate and the low frequency decoded signal.
    [14] With reference to the sixth mode of implementation of the first aspect, in an eighth mode of implementation of the first aspect, the prediction of the high-band excitation signal according to the low-frequency decoded signal or a low-frequency excitation signal includes: predicting the high band excitation signal according to the decoding rate and the low frequency excitation signal.
    [15] With reference to the first to eighth modes of implementation of the first aspect, in a ninth mode of implementation of the first aspect, after the prediction of a high frequency energy and a high band excitation signal according to the extension parameter bandwidth, the method additionally includes: determining a first correction factor according to at least one of the bandwidth extension parameter and the low frequency decoded signal, where the first correction factor includes one or more the following parameters: a voice factor, a noise gate factor, and a spectrum slope factor; and correcting the high frequency energy according to the first correction factor.
    [16] With reference to the ninth mode of implementation of the first aspect, in a tenth mode of implementation of the first aspect, the determination of a first correction factor according to at least one of the bandwidth extension parameter and the signal low-frequency decoded includes: determining the first correction factor according to the interval period, the contribution of the adaptive codebook, the contribution of the algebraic codebook and the low-frequency decoded signal.
    [17] With reference to the ninth mode of implementation of the first aspect, in an eleventh mode of implementation of the first aspect, the determination of a first correction factor according to at least one of the bandwidth extension parameter and the low frequency decoded signal includes: determining the first correction factor according to the low frequency decoded signal.
    [18] With reference to the ninth mode of implementation of the first aspect, in a twelfth mode of implementation of the first aspect, the determination of a first correction factor according to at least one of the bandwidth extension parameter and the low-frequency decoded signal includes: determining the first correction factor according to the interval period, the contribution of the adaptive codebook, the contribution of the algebraic codebook and the low-frequency decoded signal.
    [19] With reference to the ninth to twelfth modes of implementation of the first aspect, in a thirteenth mode of implementation of the first aspect, the method further includes: correcting the high frequency energy according to the interval period.
    [20] With reference to the ninth to thirteenth modes of implementation of the first aspect, in a fourteenth mode of implementation of the first aspect, the method further includes: determining a second correction factor according to at least one of the extension parameter bandwidth and the low frequency decoded signal, where the second correction factor includes at least one of a classification parameter and a type of signal; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [21] With reference to the fourteenth mode of implementation of the first aspect, in a fifteenth mode of implementation of the first aspect, the determination of a second correction factor according to at least one among the bandwidth extension parameter and the decoded low frequency signal includes: determining the second correction factor according to the bandwidth extension parameter.
    [22] With reference to the fourteenth mode of implementation of the first aspect, in a sixteenth mode of implementation of the first aspect, the determination of a second correction factor according to at least one of the bandwidth extension parameter and the low frequency decoded signal includes: determining the second correction factor according to the low frequency decoded signal.
    [23] With reference to the fourteenth mode of implementation of the first aspect, in a seventeenth mode of implementation of the first aspect, the determination of a second correction factor according to at least one of the bandwidth extension parameter and the low frequency decoded signal includes: determining the second correction factor according to the bandwidth extension parameter and the low frequency decoded signal.
    [24] With reference to the ninth to seventeenth modes of implementation of the first aspect, in an eighteenth mode of implementation of the first aspect, the method additionally includes: weighting the expected high band excitation signal and a random noise signal, for obtain a final high band excitation signal, where a weight of the weight is determined according to a value of a classification parameter and / or a voice factor of the low-frequency decoded signal.
    [25] With reference to the first to the eighteenth implementation modes of the first aspect, in a nineteenth implementation mode of the first aspect, obtaining the high frequency band signal according to the high frequency energy and the excitation signal high bandwidth includes: synthesizing the high frequency energy and the high band excitation signal, to obtain the high frequency band signal; or synthesize the high frequency energy, the high band excitation signal and a predicted LPC, to obtain the high frequency band signal, where the predicted LPC includes a predicted high frequency band LPC or a predicted band LPC broad and the expected LPC is obtained based on the LPC.
    [26] According to a second aspect, a bandwidth extension device is provided, including: an acquisition unit configured to acquire a bandwidth extension parameter, where the bandwidth extension parameter includes one or more of the following parameters: a linear prediction coefficient (LPC), an in-line spectral frequency parameter (LSF), an interval period, a decoding rate, an adaptive codebook contribution and a algebraic code; and a bandwidth extension unit, configured to perform, according to the bandwidth extension parameter acquired by the acquisition unit, the bandwidth extension on a low frequency decoded signal, to obtain a high frequency band.
    [27] With reference to the second aspect, in a first way of implementing the second aspect, the bandwidth extension unit includes: a forecast subunit, configured to predict high frequency energy and a high band excitation signal of according to the bandwidth extension parameter; and a synthesis subunit, configured to obtain the high frequency band signal according to the high frequency energy and the high band excitation signal.
    [28] With reference to the first way of implementing the second aspect, in a second way of implementing the second aspect, the high frequency energy includes a high frequency gain; and the forecast subunit is specifically configured to: predict the high frequency gain according to the LPC; and adaptively predict the high band excitation signal according to the LSF parameter, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [29] With reference to the first way of implementing the second aspect, in a third way of implementing the second aspect, high frequency energy includes a high frequency gain; and the forecast subunit is specifically configured to: predict the high frequency gain according to the LPC; and adaptively predict the high band excitation signal according to the decoding rate, the LSF parameter, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [30] With reference to the first way of implementing the second aspect, in a fourth way of implementing the second aspect, high frequency energy includes a high frequency gain; and the forecast subunit is specifically configured to: predict the high frequency gain according to the LPC; and adaptively predicting the high band excitation signal according to the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [31] With reference to the first way of implementing the second aspect, in a fifth way of implementing the second aspect, high frequency energy includes a high frequency gain; and the forecast subunit is specifically configured to: predict the high frequency gain according to the LPC; and adaptively predicting the high band excitation signal according to the decoding rate, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [32] With reference to the first way of implementing the second aspect, in a sixth way of implementing the second aspect, the high frequency energy includes a high frequency envelope; and the prediction subunit is specifically configured to: predict the high frequency envelope according to the low frequency decoded signal; and predicting the high-band excitation signal according to the low-frequency decoded signal or a low-frequency excitation signal, where the low-frequency excitation signal is the sum of the adaptive codebook contribution and the contribution of the algebraic code book.
    [33] With reference to the sixth mode of implementation of the second aspect, in a seventh mode of implementation of the second aspect, the forecast subunit is specifically configured to: predict the high frequency envelope according to the low frequency decoded signal; and predicting the high band excitation signal according to the decoding rate and the low frequency excitation signal.
    [34] With reference to the sixth mode of implementation of the second aspect, in an eighth mode of implementation of the second aspect, the forecast subunit is specifically configured to: predict the high frequency envelope according to the decoded low frequency signal; and predicting the high band excitation signal according to the decoding rate and the low frequency decoding signal.
    [35] With reference to the first to eighth modes of implementation of the second aspect, in a ninth mode of implementation of the second aspect, the bandwidth extension unit additionally includes: a first correction subunit, configured for: after power high frequency and high band excitation signal are predicted according to the bandwidth extension parameter, determine a first correction factor according to at least one of the bandwidth extension parameter and the decoded signal of low frequency, where the first correction factor includes one or more of the following parameters: a voice factor, a noise gate factor and a spectrum slope factor; and correcting the high frequency energy according to the first correction factor.
    [36] With reference to the ninth mode of implementation of the second aspect, in a tenth mode of implementation of the second aspect, the first correction subunit is specifically configured to: determine the first correction factor according to the interval period, the contribution the adaptive codebook and the contribution of the algebraic codebook; and correcting the high frequency energy according to the first correction factor.
    [37] With reference to the ninth mode of implementation of the second aspect, in an eleventh mode of implementation of the second aspect, the first correction subunit is specifically configured to: determine the first correction factor according to the low frequency decoded signal ; and correcting the high frequency energy according to the first correction factor.
    [38] With reference to the ninth mode of implementation of the second aspect, in a twelfth mode of implementation of the second aspect, the first correction subunit is specifically configured to: determine the first correction factor according to the interval period, the contribution of the adaptive codebook, the contribution of the algebraic codebook and the low-frequency decoded signal; and correcting the high frequency energy according to the first correction factor.
    [39] With reference to the ninth to twelfth modes of implementation of the second aspect, in a thirteenth mode of implementation of the second aspect, the bandwidth extension unit additionally includes: a second correction subunit, configured to correct power high frequency according to the interval period.
    [40] With reference to the ninth to thirteenth modes of implementation of the second aspect, in a fourteenth mode of implementation of the second aspect, the bandwidth extension unit additionally includes: a third correction subunit, configured to determine a second correction factor according to at least one of the bandwidth extension parameter and the low-frequency decoded signal, wherein the second correction factor includes at least one among a classification parameter and a signal type; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [41] With reference to the fourteenth mode of implementation of the second aspect, in a fifteenth mode of implementation of the second aspect, the third correction subunit is specifically configured to: determine the second correction factor according to the extension parameter of bandwidth; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [42] With reference to the fourteenth implementation mode of the second aspect, in a sixteenth implementation mode of the second aspect, the third correction subunit is specifically configured to: determine the second correction factor according to the decoded low signal frequency; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [43] With reference to the fourteenth mode of implementation of the second aspect, in a seventeenth mode of implementation of the second aspect, the third correction subunit is specifically configured to: determine the second correction factor according to the extension parameter of bandwidth and low frequency decoded signal; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [44] With reference to the ninth to seventeenth modes of implementation of the second aspect, in an eighteenth mode of implementation of the second aspect, the bandwidth extension unit additionally includes: a weighting subunit, configured to weight the expected signal high band excitation and a random noise signal, to obtain a final high band excitation signal, in which a weight of the weight is determined according to a value of a classification parameter and / or a signal factor of the signal low frequency decoded.
    [45] With reference to the first to the eighteenth implementation modes of the second aspect, in a nineteenth implementation mode of the second aspect, the synthesis subunit is specifically configured to: synthesize the high frequency energy and the band excitation signal high, to obtain the high frequency band signal; or synthesize the high frequency energy, the high band excitation signal and a predicted LPC, to obtain the high frequency band signal, where the predicted LPC includes a predicted high frequency band LPC or a predicted band LPC broad and the expected LPC is obtained based on the LPC.
    [46] In the modalities of the present invention, bandwidth extension is performed, using a bandwidth extension parameter and using the bandwidth extension parameter, on a low frequency decoded signal. thereby recovering a high frequency band signal. The high frequency band signal recovered using the bandwidth extension method and apparatus in the embodiments of the present invention is close to an original high frequency band signal, and the quality is satisfactory. BRIEF DESCRIPTION OF THE DRAWINGS
    [47] To describe the technical solutions in the modalities of the present invention more clearly, the following briefly introduces the accompanying drawings required to describe the modalities of the present invention. Apparently, the accompanying drawings in the description below show merely some embodiments of the present invention, and a person of ordinary skill in the art can still derive other designs from these attached drawings without creative efforts.
    [48] Figure 1 is a flow chart of a bandwidth extension method according to an embodiment of the present invention;
    [49] Figure 2 is a block diagram of an implementation of a bandwidth extension method according to an embodiment of the present invention;
    [50] Figure 3 is a block diagram of an implementation of a method of extending bandwidth over a time domain and a frequency domain according to an embodiment of the present invention;
    [51] Figure 4 is a block diagram of an implementation of a method of extending bandwidth in a frequency domain according to an embodiment of the present invention;
    [52] Figure 5 is a block diagram of an implementation of a method of extending bandwidth in a time domain according to an embodiment of the present invention;
    [53] Figure 6 is a schematic structural diagram of a bandwidth extension apparatus according to an embodiment of the present invention;
    [54] Figure 7 is a schematic structural diagram of a bandwidth extension unit in a bandwidth extension apparatus according to an embodiment of the present invention;
    [55] Figure 8 is a schematic structural diagram of a bandwidth extension unit in a bandwidth extension apparatus according to another embodiment of the present invention;
    [56] Figure 9 is a schematic structural diagram of a bandwidth extension unit in a bandwidth extension apparatus according to another embodiment of the present invention;
    [57] Figure 10 is a schematic structural diagram of a bandwidth extension unit in a bandwidth extension apparatus according to another embodiment of the present invention;
    [58] Figure 11 is a schematic structural diagram of a bandwidth extension unit in a bandwidth extension apparatus according to another embodiment of the present invention; and
    [59] Figure 12 is a schematic structural diagram of a decoder according to an embodiment of the present invention. DESCRIPTION OF THE MODALITIES
    [60] The following clearly describes technical solutions in the modalities of the present invention with reference to the accompanying drawings in the modalities of the present invention. Apparently, the described modalities are some, but not all, of the present invention. All other modalities obtained by individuals of ordinary skill in the art based on the modalities of the present invention without creative efforts should fall within the scope of protection of the present invention.
    [61] In the modalities of the present invention, the bandwidth extension is performed on a low frequency signal according to any one of a combination of some among a decoding rate, an LPC coefficient (an LSF parameter) and a interval period that are obtained by directly decoding a code stream, an adaptive codebook contribution and an algebraic codebook contribution that are obtained by intermediate decoding, and a low frequency signal obtained by final decoding, retrieving, thus, a high frequency band signal.
    [62] The following describes in detail a method of extending bandwidth according to an embodiment of the present invention with reference to Figure 1, which may include the steps to follow.
    [63] S11: A decoder acquires a bandwidth extension parameter, where the bandwidth extension parameter includes one or more of the following parameters: a linear prediction coefficient (LPC), a spectral frequency parameter in line (LSF), an interval period, a contribution from the adaptive codebook and a contribution from the algebraic codebook; and
    [64] The decoder may be arranged on a hardware device such as a mobile phone, a tablet computer, a computer, a television set, a converter or a game console on which a decoding operation needs to be performed, and operate under the control of processors on these hardware devices. The decoder can also be an independent hardware device, where the hardware device includes a processor and the hardware device operates under the control of the processor.
    [65] Specifically, the LPC is a coefficient of a linear prediction filter and the linear prediction filter can describe a basic feature of a sound channel model and the LPC also reflects a trend of changing energy from a signal to a frequency domain. The LSF parameter is a way of representing the frequency domain of the LPC.
    [66] In addition, when a person produces a voice sound, an air flow passes through a glottis, and causes the vocal cords to produce an oscillatory relaxation vibration, thereby creating an almost periodic pulse air flow. This airflow excites a sound channel and then the voice sound is produced, which is also referred to as a speech. Voice speech carries most of the energy in a speech. Such a frequency at which the vocal cords vibrate is referred to as a fundamental frequency, and a corresponding period is referred to as the interval period.
    [67] The decoding rate refers to the fact that, in a speech encoding algorithm, both encoding and decoding are processed according to a rate (a bit rate) that is defined in advance, and for different rates of decoding, processing modes or parameters may be different.
    [68] The adaptive codebook contribution is an almost periodic portion of a residual signal after a speech signal is analyzed using LPC. The contribution of the algebraic code book refers to a portion of near noise in the residual signal after the speech signal is analyzed using the LPC.
    [69] In this document, the LPC and the LSF parameter can be obtained by directly decoding the code flow; the contribution of the adaptive codebook and the contribution of the algebraic codebook can be combined to obtain a low frequency excitation signal.
    [70] The adaptive codebook contribution reflects an almost periodic constituent of the signal, and the algebraic codebook contribution reflects an almost noise constituent of the signal.
    [71] S12: The decoder performs, according to the bandwidth extension parameter, bandwidth extension on a low frequency decoded signal, to obtain a high frequency band signal.
    [72] For example, first, high frequency energy and a high band excitation signal are predicted according to the bandwidth extension parameter, where high frequency energy can include a high frequency envelope or a high frequency gain; then, the high frequency band signal is obtained according to the high frequency energy and the high band excitation signal.
    [73] Additionally, for a difference between a time domain and a frequency domain, the bandwidth extension parameter involved in predicting high frequency energy or the high band excitation signal may be different.
    [74] If the bandwidth extension is performed in the time domain and the frequency domain, the high frequency energy forecast and a high band excitation signal according to the bandwidth extension parameter can include : predict the high frequency gain according to the LPC; and adaptively predict the high band excitation signal according to the LSF parameter, the contribution of the adaptive codebook and the contribution of the algebraic codebook. In addition, the high band excitation signal can be additionally predicted in an adaptable way according to the decoding rate, the LSF parameter, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [75] Optionally, if the bandwidth extension is performed in the time domain, the high frequency energy forecast and a high band excitation signal according to the bandwidth extension parameter can include: predict the high frequency gain according to the LPC; and adaptively predicting the high band excitation signal according to the contribution of the adaptive codebook and the contribution of the algebraic codebook. In addition, the high band excitation signal can be additionally predicted in an adaptable manner according to the decoding rate, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [76] Optionally, if the bandwidth extension is performed in the frequency domain, the high frequency energy forecast and a high band excitation signal according to the bandwidth extension parameter can include: predict the high frequency envelope according to the low frequency decoded signal; and predicting the high band excitation signal according to the low frequency decoded signal or a low frequency excitation signal. In this document, the low-frequency excitation signal is the sum of the contribution of the adaptive codebook and the contribution of the algebraic codebook. In addition, the high band excitation signal can also be predicted according to the decoding rate and the low frequency decoded signal; or the high band excitation signal can also be predicted according to the decoding rate and the low frequency excitation signal.
    [77] In addition, after predicting high frequency energy and a high band excitation signal according to the bandwidth extension parameter, the bandwidth extension method in this embodiment of the present invention may additionally include: determine a first correction factor according to at least one of the bandwidth extension parameter and the low-frequency decoded signal, where the first correction factor includes one or more of the following parameters: a voice factor, a noise gate factor and a spectrum skew factor; and correcting the high frequency energy according to the first correction factor. For example, the speech factor or the noise gate factor can be determined according to the bandwidth extension parameter, and the spectrum slope factor can be determined according to the low frequency decoded signal.
    [78] The determination of a first correction factor according to the bandwidth extension parameter and the low frequency decoded signal may include: determining the first correction factor according to the low frequency decoded signal; or, determine the first correction factor according to the interval period, the contribution of the adaptive codebook and the contribution of the algebraic codebook; or, determine the first correction factor according to the interval period, the contribution of the adaptive codebook, the contribution of the algebraic codebook and the low-frequency decoded signal.
    [79] In addition, the bandwidth extension method in this embodiment of the present invention may additionally include: correcting the high frequency energy according to the interval period.
    [80] Additionally, the bandwidth extension method in this embodiment of the present invention may additionally include: determining a second correction factor according to at least one of the bandwidth extension parameter and the low frequency decoded signal , in which the second correction factor includes at least one of a classification parameter and a signal type; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [81] Specifically, determining a second correction factor according to at least one of the bandwidth extension parameter and the low frequency decoded signal may include: determining the second correction factor according to the bandwidth extension; or, determine the second correction factor according to the low frequency decoded signal; or, determine the second correction factor according to the bandwidth extension parameter and the low frequency decoded signal.
    [82] Furthermore, the method of extending bandwidth in this embodiment of the present invention may additionally include: correcting the high-band excitation signal according to a random noise signal and the decoding rate.
    [83] In addition, obtaining the high frequency band signal according to the high frequency energy and the high band excitation signal may include: synthesizing the high frequency energy and the high band excitation signal, for obtain the high frequency band signal; or synthesize the high frequency energy, the high band excitation signal and a predicted LPC, to obtain the high frequency band signal, where the predicted LPC includes a predicted high frequency band LPC or a predicted band LPC broad and the expected LPC is obtained based on the LPC. The "broadband" in the broadband LPC in this document includes a low frequency band and a high frequency band.
    [84] It can be seen from the above that, in this modality of the present invention, bandwidth extension is performed, using a bandwidth extension parameter, in a low frequency decoded signal, recovering from that mode, a high frequency band signal. The high frequency band signal recovered using the bandwidth extension method in this embodiment of the present invention is close to an original high frequency band signal, and the quality is satisfactory.
    [85] That is, in the bandwidth extension method in this modality of the present invention, the high frequency energy is predicted with the complete use of a low frequency parameter obtained by direct coding of a code stream, a decoded parameter intermediate, or the low frequency signal obtained by final decoding; a high band excitation signal is adaptably predicted according to a low frequency excitation signal, so that the high frequency band signal that is finally produced is close to the original high frequency band signal, thereby improving mode, the quality of the signal produced.
    [86] The following describes specific embodiments of the present invention in detail with reference to the accompanying drawings.
    [87] First, Figure 2 shows a schematic flowchart of a bandwidth extension method according to an embodiment of the present invention.
    [88] As shown in Figure 2, first, any of or a combination of some of a speech factor, a noise gate factor, a spectrum skew factor and a value of a classification parameter is calculated accordingly with any of or a combination of any of a decoding rate, an LPC (or an LSF parameter) and an interval period that are obtained by directly decoding a code stream, parameters as a contribution from the adaptive codebook and a contribution from the algebraic code book that are obtained by intermediate decoding and a low frequency signal obtained by final decoding. The voice factor is a ratio between the contribution of the adaptive codebook and the contribution of the algebraic codebook, the noise gate factor is a parameter used to represent the magnitude of a signal background noise, and the spectrum skew factor is used to represent a degree of signal spectrum skew or a tendency for a signal to change energy between different frequency bands, where the classification parameter is a parameter used to differentiate signal types. After that, a high frequency band LPC or a broad band LPC, high frequency energy (for example, a high frequency gain or a high frequency envelope) and a high band excitation signal are provided. Finally, a high frequency band signal is synthesized using the predicted high frequency energy and the high band excitation signal, or using the predicted high frequency energy and the high band excitation signal and the LPC foreseen.
    [89] Specifically, the high frequency band LPC or the broadband LPC can be predicted according to the LPC obtained by decoding.
    [90] The high frequency envelope or the high frequency gain can be predicted as follows:
    [91] For example, the high frequency gain or the high frequency envelope is predicted using the predicted LPC and the LPC obtained by decoding, or a relationship between high and low frequencies of the low frequency decoded signal.
    [92] Alternatively, for example, for different types of signals, different correction factors are calculated to correct the expected high frequency gain or high frequency envelope. For example, the expected high frequency envelope or high frequency gain can be corrected using a weighted value or weighted values of any or some of the classification parameters, the spectrum skew factor, the voice factor and the noise gate factor of the low frequency decoded signal. Alternatively, for a signal whose interval period is stable, the predicted high-frequency envelope can be further corrected using the interval period.
    [93] The high band excitation signal can be predicted as follows:
    [94] For example, for different decoding rates or different types of signals, high band excitation signals are provided by selecting adaptively low frequency signals with different frequency bands and obtained by decoding, or by using different forecasting algorithms.
    [95] In addition, the predicted high band excitation signal and a random noise signal are weighted to obtain a final high band excitation signal, where a weight is determined according to the value of the classification parameter and / or the voice factor of the low-frequency decoded signal.
    [96] Finally, the high frequency band signal is synthesized using predicted high frequency energy and the high band excitation signal, or using the predicted high frequency energy and high band excitation signal. and the predicted LPC.
    [97] It can be seen from the aforementioned that, in the bandwidth extension method in this modality of the present invention, the high frequency energy is predicted with the complete use of a low frequency parameter obtained by direct coding of a flow codes, an intermediate decoded parameter, or a low frequency signal obtained by final decoding; a high band excitation signal is adaptively predicted according to a low frequency excitation signal, so that a high frequency band signal that is finally produced is close to an original high frequency band signal, improving, thus, the quality of the signal produced.
    [98] For a difference between a time domain and a frequency domain, a specific implementation process for the bandwidth extension method in this embodiment of the present invention may vary. The following describes separately the specific modalities for the time domain and the frequency domain, for the frequency domain and for the time domain with reference from Figure 3 to Figure 5.
    [99] As shown in Figure 3, in a specific implementation process of performing bandwidth extension in a time domain and a frequency domain:
    [100] First, a broadband LPC is predicted according to an LPC obtained by decoding.
    [101] Thereafter, a high frequency gain is predicted using a relationship between the predicted broadband LPC and the LPC obtained by decoding. In addition, for different types of signals, different correction factors are calculated to correct the predicted high frequency gain. For example, the predicted high frequency gain is corrected using a classification parameter, a spectrum slope factor, a voice factor and a noise gate factor of a low frequency decoded signal. A corrected high frequency gain is proportional to a minimum noise gate factor ng_min, proportional to a fmerit value of the classification parameter, proportional to an opposite number of the tilt spectrum slope factor and inversely proportional to the voice_fac voice factor. In this case, a higher high frequency gain indicates a smaller spectrum skew factor; a higher background noise indicates a higher noise gate factor; a stronger speech characteristic indicates a higher value of the classification parameter. For example, the corrected high frequency gain = gain * (1-tilt) * fmerit * (30 + ng_min) * (1.6-voice_fac). In the present document, a noise gate factor evaluated in each frame needs to be compared to a given threshold; therefore, when the noise gate factor evaluated in each frame is less than the given threshold, the minimum noise gate factor is equal to the noise gate factor evaluated in each frame; otherwise, the minimum noise gate factor is equal to the given threshold.
    [102] Furthermore, for different decoding rates or different types of signals, high-band excitation signals are provided by selecting adaptively low-frequency signals with different frequency bands and obtained by decoding, or by using different forecasting algorithms. For example, when a decoding rate is greater than a given value, a low frequency excitation signal (the sum of the adaptive codebook contribution and the algebraic codebook contribution) with a frequency band adjacent to the high frequency band is used as the high band excitation signal; otherwise, a signal with a frequency band whose coding quality is better (that is, a difference value between LSF parameters is lower) is adaptively selected from low frequency excitation signals as the high band excitation using the difference value between the LSF parameters. It can be understood that different decoders can select different data values. For example, a broadband codec with multiple adaptive rates (AMR-WB) supports decoding rates such as 12.65 kbps, 15.85 kbps, 18.25 kbps, 19.85 kbps, 23.05 kbps and 23.85 kbps, and then the AMR-WB codec can select 19.85 kbps as the given value.
    [103] An ISF parameter (the ISF parameter is a group of numbers, and is the same as an order and an LPC coefficient) is a mode of representing a frequency domain of the LPC coefficient and reflects a change in energy of a speech / audio signal in the frequency domain. An ISF value corresponds approximately to an entire frequency band from a low frequency to a high frequency of the speech / audio signal, and each value of the ISF parameter corresponds to a corresponding frequency value.
    [104] In an embodiment of the present invention, in which a signal with a frequency band whose coding quality is better (that is, a difference value between LSF parameters is lower) is selected adaptively from low frequency excitation as the high band excitation signal using the difference value between the LSF parameters can include: a difference value between each two LSF parameters to be calculated, to obtain a group of difference values of the parameters LSF; a minimum difference value is sought, and a frequency bin corresponding to the LSF parameter is determined according to the minimum difference value; and a frequency domain excitation signal with a frequency band is selected from frequency domain excitation signals according to the frequency bin, and is used as an excitation signal with a high frequency band. There are multiple selection modes. If the frequency bin is F1, a signal with a frequency band of a required length can be selected from an F1-F frequency pin, and is used as the high-band excitation signal, where F> = 0, and the specifically selected length is determined according to the bandwidth and a signal resource of a high frequency band signal that needs to be retrieved.
    [105] In addition, when the frequency band whose coding quality is best is adaptively selected from low frequency excitation signals, to a music signal or a speech signal, a minimum selection frequency bin different start is selected. For example, for the speech signal, the selection can be made adaptably from a range of 2 to 6 kHz; for the music signal, the selection can be made adaptively from a range of 1 to 6 kHz. The predicted high band excitation signal and a random noise signal can be additionally weighted to obtain a final high band excitation signal, where a weight of the weight is determined according to a value of a classification parameter and / or a voice factor of the low-frequency decoded signal:
    where exc [n] is the predicted high band excitation signal, random [n] is the random noise signal, α is a weight of the predicted high band excitation signal, β is a weight of the random noise signal, Y is a value that is predefined when the weight of the predicted high band excitation signal is calculated to be α, fmerit is the value of the classification parameter, and voice_fac is the voice factor.
    [106] It is easy to understand that signal classification methods are different and, therefore, high band excitation signals are predicted by selecting adaptively low frequency signals with different frequency bands and obtained by decoding or using decoding. different forecasting algorithms. For example, the signals can be classified into speech signals and music signals, where the speech signals can be further classified into muted sounds, beeps and transition sounds. Alternatively, the signals can be further classified into transient and non-transient signals and so on.
    [107] Finally, the high frequency band signal is synthesized using the predicted high frequency gain and the high band excitation signal and the predicted LPC. The high band excitation signal is corrected using the predicted high frequency gain, and then a high band excitation corrected signal passes through an LPC synthesis filter to obtain a high frequency band signal that is finally, produced; or the high band excitation signal passes through an LPC synthesis filter to obtain a high frequency band signal, and then the high frequency band signal is corrected using the high frequency gain to obtain a high frequency band signal that is finally produced. The LPC synthesis filter is a linear filter, and therefore a correction before synthesis is the same as a correction after synthesis. That is, a result of correction of the high band excitation signal before synthesis with the use of high frequency gain is the same as a result of correction of the high band excitation signal after synthesis with the use of high gain frequency and, therefore, there is no sequential order for correction.
    [108] In this document, in a synthesis process, the high band excitation signal obtained from the frequency domain is converted into the high band excitation signal from the time domain, the high band excitation signal from the time domain. and the high frequency gain of the time domain are used as synthesis filter inputs, and the predicted LPC coefficient is used as a synthesis filter coefficient, which thereby obtains the synthesized high frequency band signal.
    [109] It can be seen from the aforementioned that, in the bandwidth extension method in this modality of the present invention, the high frequency energy is predicted with the complete use of a low frequency parameter obtained by direct coding of a flow codes, an intermediate decoded parameter, or a low frequency signal obtained by final decoding; a high band excitation signal is adaptively predicted according to a low frequency excitation signal, so that a high frequency band signal that is finally produced is close to an original high frequency band signal, improving, thus, the quality of the signal produced.
    [110] As shown in Figure 4, in a specific implementation process of extending bandwidth in a frequency domain:
    [111] First, a high frequency band LPC is predicted according to an LPC obtained by decoding.
    [112] After that, a high-frequency band signal that needs to be extended is divided into M sub-bands, and high-frequency envelopes from the M sub-bands are provided. For example, N frequency bands adjacent to the high frequency band signal are selected from a low frequency decoded signal, the energy or amplitude of the N frequency bands is calculated, and the high frequency envelopes of the M sub- bands are predicted according to a size relationship between the energy or the amplitude of the N frequency bands. In this document, M and N are both default values. For example, the high-frequency band signal is divided into M = 2 sub-bands, and N = 2 or 4 sub-bands adjacent to the high-frequency band signal are selected.
    [113] Additionally, the predicted high frequency envelopes are corrected using a low frequency decoded signal classification parameter, an interval period, an energy or an amplitude ratio between high and low frequencies of the low frequency signal. , a voice factor and a noise gate factor. In this document, high frequencies and low frequencies can be divided differently for different low frequency signals. For example, if the bandwidth of a low frequency signal is 6 kHz, 0 to 3 kHz and 3 to 6 kHz can be used respectively as low frequencies and high frequencies of the low frequency signal, or 0 to 4 kHz and 4 to 6 kHz can be used respectively as low frequencies and high frequencies of the low frequency signal.
    [114] A corrected high-frequency envelope is proportional to a minimum noise gate factor ng_min, proportional to a fmerit value of the classification parameter, proportional to the opposite number of the tilt spectrum slope factor and inversely proportional to the voice_fac voice factor . In addition, for a signal whose pitch interval period is stable, a corrected high frequency envelope is proportional to the interval period. In this case, the higher high frequency energy indicates a smaller spectrum skew factor; a higher background noise indicates a higher noise gate factor; a stronger speech characteristic indicates a higher value of the classification parameter. For example, the corrected high-frequency envelope gain * = (1-tilt) * fmerit * (30 + ng_min) * (1,6-voice_fac) * (pitch / 100).
    [115] Then, when the decoding rate is greater than or equal to a given threshold, a frequency band of a low frequency signal adjacent to the high frequency band signal is selected to predict a high band excitation signal; or, when a decoding rate is less than a given threshold, a subband whose encoding quality is better is selected in an adaptive way to predict a high band excitation signal. In this document, the threshold data can be an empirical value.
    [116] In addition, the predicted high band excitation signal is weighted using a random noise signal, and a weighted value is determined by the low frequency signal rating parameter. A weight of the random noise signal is proportional to a size of a low frequency signal rating parameter:
    where exc [n] is the predicted high band excitation signal, random [n] is the random noise signal, α is a weight of the predicted high band excitation signal, β is the weight of the random noise signal, Y is a value that is predefined when the weight of the predicted high band excitation signal is calculated to be α, and fmerit is a value of the rating parameter.
    [117] Finally, the high frequency band signal is synthesized using the predicted high frequency envelope and the high band excitation signal.
    [118] In this document, a synthesis process can directly multiply the high frequency excitation signal of the frequency domain by the high frequency envelope of the frequency domain, to obtain the synthesized high frequency band signal.
    [119] It can be seen from the aforementioned that, in the bandwidth extension method in this modality of the present invention, the high frequency energy is predicted with the complete use of a low frequency parameter obtained by direct coding of a flow codes, an intermediate decoded parameter, or a low frequency signal obtained by final decoding; a high band excitation signal is adaptively predicted according to a low frequency excitation signal, so that a high frequency band signal that is finally produced is close to an original high frequency band signal, improving, thus, the quality of the signal produced.
    [120] As shown in Figure 5, in a specific implementation process of extending bandwidth in a time domain:
    [121] First, a broadband LPC is predicted according to an LPC obtained by decoding.
    [122] Thereafter, a high frequency band signal that needs to be extended is divided into M subframes, and high frequency gains from the M subframes are predicted using a relationship between the predicted broadband LPC and the obtained LPC by decoding.
    [123] Thereafter, a high frequency gain from a current subframe is predicted using a low frequency signal or a low frequency excitation signal from the current subframe or a current frame.
    [124] Additionally, the predicted high frequency gain is corrected using a low frequency decoded signal rating parameter, an interval period, an energy or an amplitude ratio between high and low frequencies of the low frequency signal , a voice factor and a noise gate factor. A corrected high frequency gain is proportional to a minimum noise gate factor ng_min, proportional to a fmerit value of the classification parameter, proportional to the opposite number of the tilt spectrum slope factor and inversely proportional to the voice_fac voice factor. In addition, for a signal whose pitch interval period is stable, a corrected high frequency gain is proportional to the interval period. In this case, the higher high frequency energy indicates a smaller spectrum skew factor; a higher background noise indicates a higher noise gate factor; a stronger speech characteristic indicates a higher value of the classification parameter. For example, the corrected high frequency gain gain * = (1-tilt) * fmerit * (30 + ng_min) * (1,6-voice_fac) * (pitch / 100), where tilt is the spectrum skew factor , fmerit is the value of the classification parameter, ng_min is the minimum noise gate factor, voice_fac is the voice factor and pitch is the interval period.
    [125] Then, when the decoding rate is greater than or equal to a given threshold, a frequency band of the low frequency decoded signal adjacent to the high frequency band signal is selected to predict a high band excitation signal; or, when a decoding rate is less than a given threshold, the frequency range whose encoding quality is best is adaptively selected to predict a high-band excitation signal. That is, a low frequency excitation signal (a contribution from the adaptive codebook and a contribution from the algebraic codebook) with a frequency band adjacent to the high frequency band signal can be used as the band excitation signal. high.
    [126] In addition, the predicted high band excitation signal is weighted using a random noise signal, and a weighted value is determined by the low frequency signal rating parameter and a weighted voice factor value.
    [127] Finally, the high frequency band signal is synthesized using the predicted high frequency gain and the high band excitation signal and the predicted LPC.
    [128] In this document, a synthesis process can be to use the high band excitation signal of the time domain and the high frequency gain of the time domain as inputs of a synthesis filter, and use the predicted LPC coefficient as a coefficient of the synthesis filter, which thereby obtains the synthesized high frequency band signal.
    [129] It can be seen from the above that, in the method of extending bandwidth in this modality of the present invention, high frequency energy is predicted with the complete use of a low frequency parameter obtained by direct coding of a stream codes, an intermediate decoded parameter, or a low frequency signal obtained by final decoding; a high band excitation signal is adaptively predicted according to a low frequency excitation signal, so that a high frequency band signal that is finally produced is close to an original high frequency band signal, improving, thus, the quality of the signal produced.
    [130] From Figure 6 to Figure 11, schematic structural diagrams of a bandwidth extension apparatus according to an embodiment of the present invention are shown. As shown in Figure 6, a bandwidth extension device 60 includes an acquisition unit 61 and a bandwidth extension unit 62. Acquisition unit 61 is configured to acquire a bandwidth extension parameter, where the bandwidth extension parameter includes one or more of the following parameters: a linear prediction coefficient (LPC), an in-line spectral frequency parameter (LSF), an interval period, a decoding rate, a contribution adaptive codebook and a contribution from the algebraic codebook. The bandwidth extension unit 62 is configured to perform, according to the bandwidth extension parameter acquired by the acquisition unit 61, bandwidth extension on a low frequency decoded signal, to obtain a high frequency band.
    [131] Additionally, as shown in Figure 7, the bandwidth extension unit 62 includes a forecast subunit 621 and a synthesis subunit 622. The forecast subunit 621 is configured to predict high frequency energy and a high band excitation according to the bandwidth extension parameter. The synthesis subunit 622 is configured to obtain the high frequency band signal according to the high frequency energy and the high band excitation signal. Specifically, the synthesis subunit 622 is configured to: synthesize the high frequency energy and the high band excitation signal, to obtain the high frequency band signal; or synthesize the high frequency energy, the high band excitation signal and a predicted LPC, to obtain the high frequency band signal, where the predicted LPC includes a predicted high frequency band LPC or a predicted band LPC broad and the expected LPC is obtained based on the LPC.
    [132] Specifically, high frequency energy includes a high frequency gain; and the forecast subunit 621 is configured to: predict the high frequency gain according to the LPC; and adaptively predict the high band excitation signal according to the LSF parameter, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [133] Alternatively, high frequency energy includes a high frequency gain; and the forecast subunit 621 is configured to: predict the high frequency gain according to the LPC; and adaptively predict the high band excitation signal according to the decoding rate, the LSF parameter, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [134] Alternatively, high frequency energy includes a high frequency gain; and the forecast subunit 621 is configured to: predict the high frequency gain according to the LPC; and adaptively predicting the high band excitation signal according to the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [135] Alternatively, high frequency energy includes a high frequency gain; and the forecast subunit 621 is configured to: predict the high frequency gain according to the LPC; and adaptively predicting the high band excitation signal according to the decoding rate, the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [136] Alternatively, high frequency energy includes a high frequency envelope; and the forecast subunit 621 is configured to: predict the high frequency envelope according to the low frequency decoded signal; and predicting the high-band excitation signal according to the low-frequency decoded signal or a low-frequency excitation signal, where the low-frequency excitation signal is the sum of the adaptive codebook contribution and the contribution of the algebraic code book.
    [137] Alternatively, high frequency energy includes a high frequency envelope; the forecast subunit 621 is configured to predict the high frequency envelope according to the low frequency decoded signal, and predict the high band excitation signal according to the decoding rate and the low frequency decoded signal.
    [138] Alternatively, high frequency energy includes a high frequency envelope; the forecast subunit 621 is configured to predict the high frequency envelope according to the low frequency decoded signal, and to predict the high band excitation signal according to the decoding rate and the low frequency excitation signal.
    [139] In addition, the bandwidth extension unit 62 additionally includes a first correction subunit 623, as shown in Figure 8. The first correction subunit 26 is configured for: after the high frequency energy and the high band excitation are predicted according to the bandwidth extension parameter, determine a first correction factor according to at least one of the bandwidth extension parameter and the low frequency decoded signal; and correcting the high frequency energy according to the first correction factor, where the first correction factor includes one or more of the following parameters: a voice factor, a noise gate factor and a spectrum slope factor.
    [140] Specifically, the first correction subunit 623 is configured to determine the first correction factor according to the interval period, the contribution of the adaptive codebook and the contribution of the algebraic codebook; and correcting the high frequency energy according to the first correction factor. Alternatively, the first correction subunit is specifically configured to: determine the first correction factor according to the low frequency decoded signal; and correcting the high frequency energy according to the first correction factor. Alternatively, the first correction subunit is specifically configured to: determine the first correction factor according to the interval period, the contribution of the adaptive codebook, the contribution of the algebraic codebook and the low-frequency decoded signal; and correcting the high frequency energy according to the first correction factor.
    [141] In addition, the bandwidth extension unit 62 additionally includes a second correction subunit 624, as shown in Figure 9, configured to correct the high frequency energy according to the interval period.
    [142] In addition, the bandwidth extension unit 62 additionally includes a third correction subunit 625, as shown in Figure 10, configured to determine a second correction factor according to at least one of the extension parameter of bandwidth and the low frequency decoded signal, where the second correction factor includes at least one of a classification parameter and a type of signal; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [143] Specifically, the third correction subunit 625 is configured to determine the second correction factor according to the bandwidth extension parameter; and correcting the high frequency energy and the high band excitation signal according to the second correction factor. Alternatively, the third correction subunit 625 is configured to determine the second correction factor according to the low frequency decoded signal; and correcting the high frequency energy and the high band excitation signal according to the second correction factor. The third correction subunit 625 is configured to determine the second correction factor according to the bandwidth extension parameter and the low frequency decoded signal; and correcting the high frequency energy and the high band excitation signal according to the second correction factor.
    [144] Additionally, the bandwidth extension unit 62 additionally includes a weighting subunit 626, as shown in Figure 11, configured to weight the predicted high band excitation signal and a random noise signal to obtain a signal high band excitation end, where a weighting weight is determined according to a value of a classification parameter and / or a voice factor of the low frequency decoded signal.
    [145] In one embodiment of the present invention, the bandwidth extension apparatus 60 may additionally include a processor, wherein the processor is configured to control units included in the bandwidth extension apparatus.
    [146] It can be seen from the above that the bandwidth extension apparatus in this embodiment of the present invention provides for high frequency energy with the complete use of a low frequency parameter obtained by direct coding of a code stream, an intermediate decoded parameter, or a low frequency signal obtained by final decoding; adaptively provides for a high-band excitation signal according to a low-frequency excitation signal, so that a high-frequency band signal that is finally produced is close to an original high-frequency band signal, thereby improving mode, the quality of the signal produced.
    [147] Figure 12 shows a schematic structural diagram of a decoder 120 according to an embodiment of the present invention. Decoder 120 includes processor 121 and memory 122.
    [148] Processor 121 implements a method of extending bandwidth in one embodiment of the present invention. That is, processor 121 is configured to: acquire a bandwidth extension parameter, where the bandwidth extension parameter includes one or more of the following parameters: a linear prediction coefficient (LPC), a parameter of in-line spectral frequency (LSF), an interval period, a decoding rate, an adaptive codebook contribution and an algebraic codebook contribution; and performing, according to the bandwidth extension parameter, the bandwidth extension on a low frequency decoded signal, to obtain a high frequency band signal. Memory 122 is configured to store instructions to be executed by processor 121.
    [149] It should be understood that a solution described in each claim of the present invention should also be considered as a modality and is a feature in the claim and can be combined. For example, different branching steps performed after the determination steps in the present invention can be used as different modalities.
    [150] A person of ordinary skill in the art may be aware that, in combination with the examples described in the modalities disclosed in this specification, unit steps and algorithms can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are performed by hardware or software depends on model limitation conditions and particular requests for technical solutions. A person skilled in the art may use different methods to implement the functions described for each particular request, but the implementation should not be considered to be beyond the scope of the present invention.
    [151] It can be clearly understood by a person skilled in the art that, for the purpose of a brief and convenient description, for a detailed work process of the aforementioned system, apparatus and unit, reference can be made to a corresponding process in the modalities of previously mentioned methods, and the details are not described again in this document.
    [152] In some modalities provided in the present application, it should be understood that the revealed system, apparatus and method can be implemented in other ways. For example, the described apparatus modalities are merely exemplary. For example, the unit division is merely a logical function division and can be another division in an actual implementation. For example, a plurality of units or components can be combined or integrated into another system, or some characteristics can be ignored or not realized. In addition, mutual couplings or direct couplings or communication connections displayed or discussed can be implemented using some interfaces. Indirect couplings or communication connections between devices or units can be implemented in electronic, mechanical or other ways.
    [153] The units described as separate parts may or may not be physically separated, and the parts displayed as units may or may not be physical units, may be located in one position, or may be distributed in a plurality of network units. Some or all of the units can be selected according to real needs to achieve the objectives of the modalities solutions.
    [154] In addition, functional units in the embodiments of the present invention can be integrated into a processing unit, or each of the units can physically exist alone, or two or more units are integrated into one unit.
    [155] When functions are implemented as a functional software unit and sold or used as a standalone product, the functions can be stored on a computer-readable storage medium. Based on such an understanding, essentially the technical solutions of the present invention, or the part that contributes to the prior art, or some of the technical solutions can be deployed in the form of a software product. The computer software product is stored on a storage medium, and includes some instructions for instructing a computer device (which may be a personal computer, a server or a network device) to perform all or some of the steps in the methods described in the modalities of the present invention. The aforementioned storage medium includes: any medium that can store a program code, such as a USB flash drive, a removable hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disc.
    [156] The aforementioned descriptions are merely specific modes of implementation of the present invention, however, they are not intended to limit the scope of protection of the present invention. Any variation or substitution readily understood by a person skilled in the art that falls within the scope of the technique disclosed in the present invention must fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention must be subject to the scope of protection of the claims.
    权利要求:
    Claims (10)
    [0001]
    1. Bandwidth extension method, CHARACTERIZED by the fact that it comprises: acquiring (S11) a bandwidth extension parameter, in which the bandwidth extension parameter comprises the following parameters: a linear forecast coefficient , LPC, in-line spectral frequency parameters, LSF, an adaptive codebook contribution, and an algebraic codebook contribution; and performing (S12), according to the bandwidth extension parameter, bandwidth extension on a low frequency decoded signal, to obtain a high frequency band signal; wherein the realization, according to the bandwidth extension parameter, of bandwidth extension on a low frequency decoded signal, to obtain a high frequency band signal comprises: predicting high frequency energy and a signal high band excitation according to the bandwidth extension parameter; and obtaining the high frequency signal according to the high frequency energy and the high band excitation signal; where high frequency energy is a high frequency gain; and the prediction of high frequency energy and a high band excitation signal according to the bandwidth extension parameter comprises: predicting the high frequency gain according to the LPC; and adaptively predict the high band excitation signal by selecting a frequency band from a low frequency excitation signal according to the difference in values between the LSF parameters, in which the low excitation signal frequency is a sum of the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [0002]
    2. Method, according to claim 1, CHARACTERIZED by the fact that the adaptive prediction of the high band excitation signal comprises: when the decoding rate is not greater than a given value, selectively adapt a signal with a frequency band whose coding quality is better from the low frequency excitation signal as the high band excitation signal using the difference in values between the LSF parameters.
    [0003]
    3. Method according to claim 1 or 2, CHARACTERIZED by the fact that after the prediction of a high frequency energy and a high band excitation signal according to the bandwidth extension parameter, the method additionally comprises: correcting the high frequency energy using a spectrum slope factor of the low frequency decoded signal.
    [0004]
    4. Method, according to claim 1, CHARACTERIZED by the fact that it additionally comprises: weighting the predicted high band excitation signal and a random noise signal, to obtain a final high band excitation signal, in which a weight weighting is determined according to a value of a voice factor of the low-frequency decoded signal.
    [0005]
    5. Method according to any one of claims 1 to 4, CHARACTERIZED by the fact that obtaining the high frequency band signal according to the high frequency energy and the high band excitation signal comprises: correcting the high band excitation signal using the predicted high frequency gain to obtain a high band excitation corrected signal, and passing the high band excitation corrected signal through an LPC synthesis filter to obtain the high frequency signal.
    [0006]
    6. Bandwidth extension device, CHARACTERIZED by the fact that it comprises: an acquisition unit (61), configured to acquire a bandwidth extension parameter, in which the bandwidth extension parameter comprises the following parameters: a linear prediction coefficient, LPC, in-line spectral frequency parameters, LSF, an adaptive codebook contribution, and an algebraic codebook contribution; and a bandwidth extension unit (62), configured to perform, according to the bandwidth extension parameter acquired by the acquisition unit, bandwidth extension on a low frequency decoded signal, to obtain a high frequency band signal; wherein the bandwidth extension unit comprises: a forecast subunit (621), configured to predict high frequency energy and a high band excitation signal according to the bandwidth extension parameter; and a synthesis subunit (622), configured to obtain the high frequency band signal according to the high frequency energy and the high band excitation signal; where high frequency energy is a high frequency gain; and the forecast subunit (621) is specifically configured to: predict the high frequency gain according to the LPC; and adaptively predict the high band excitation signal by selecting a frequency band from a low frequency excitation signal according to the difference in values between the LSF parameters, in which the low excitation signal frequency is a sum of the contribution of the adaptive codebook and the contribution of the algebraic codebook.
    [0007]
    7. Apparatus, according to claim 6, CHARACTERIZED by the fact that the forecast subunit (621) is specifically configured to: predict the high frequency gain according to the LPC; and when a decoding rate is not greater than a given value, adaptively select a signal with a frequency band whose coding quality is better from the low frequency excitation signal as the high band excitation signal using the difference in values between the LSF parameters.
    [0008]
    8. Apparatus according to claim 6 or 7, CHARACTERIZED by the fact that the bandwidth extension unit (62) additionally comprises: a first correction subunit (623), configured for: after high frequency energy and the high band excitation signal is predicted according to the bandwidth extension parameter, correcting the high frequency energy using a spectrum slope factor of the low frequency decoded signal.
    [0009]
    9. Apparatus according to claim 6, CHARACTERIZED by the fact that the bandwidth extension unit (62) additionally comprises: a weighting subunit (626), configured to weight the expected high band excitation signal and a random noise signal, to obtain a final high-band excitation signal, in which a weight of the weight is determined according to the value of a voice factor of the low-frequency decoded signal.
    [0010]
    10. Apparatus according to any one of claims 6 to 9, CHARACTERIZED by the fact that the synthesis subunit (622) is specifically configured to: correct the high band excitation signal using the predicted high frequency gain to obtain a corrected high band excitation signal, and passing the corrected high band excitation signal through an LPC synthesis filter to obtain the high frequency band signal.
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    法律状态:
    2018-11-13| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2020-05-12| B15K| Others concerning applications: alteration of classification|Free format text: A CLASSIFICACAO ANTERIOR ERA: G10L 21/02 Ipc: G10L 21/038 (2013.01) |
    2020-05-19| B07A| Technical examination (opinion): publication of technical examination (opinion) [chapter 7.1 patent gazette]|
    2020-09-08| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2020-12-08| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 15/04/2014, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    CN201310444398.3|2013-09-26|
    CN201310444398.3A|CN104517610B|2013-09-26|2013-09-26|The method and device of bandspreading|
    PCT/CN2014/075420|WO2015043161A1|2013-09-26|2014-04-15|Method and device for bandwidth extension|
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