Signal Classification Method and Device, and Encoding and Decoding Methods and Devices

Abstract

Embodiments of the present invention provide a signal classification method and device, and encoding and decoding methods and devices. The encoding method includes dividing a current frame into a low-frequency band signal and a high-frequency band signal, attenuating the high-frequency band signal or a to-be-encoded characteristic parameter of the high-frequency band signal according to an energy attenuation value of the low-frequency band signal, where the energy attenuation value indicates energy attenuation of the low-frequency band signal caused by encoding of the low-frequency band signal, and encoding the attenuated high-frequency band signal or the attenuated to-be-encoded characteristic parameter of the high-frequency band signal. The technical solutions according to the embodiments of the present invention can improve the effect of combining the low-frequency band signal and the high-frequency band signal at the decoder.

What is claimed is: 
     
         1 . An encoding method for processing speech/audio signals, comprising:
 dividing, by an encoder, a current frame into a low-frequency band signal and a high-frequency band signal, wherein the encoder comprises a processor;   attenuating, by the encoder, a one of the group consisting of the high-frequency band signal and a to-be-encoded characteristic parameter of the high-frequency band signal, the attenuating being according to an energy attenuation value of the low-frequency band signal, and wherein the energy attenuation value indicates energy attenuation of the low-frequency band signal caused by encoding of the low-frequency band signal; and   encoding, by the encoder, the one of the group consisting of the attenuated high-frequency band signal and the attenuated to-be-encoded characteristic parameter of the high-frequency band signal.   
     
     
         2 . The method according to  claim 1 , further comprising:
 determining a signal class of the high-frequency band signal; and   wherein the attenuating the one of the group consisting of the high-frequency band signal and the to-be-encoded characteristic parameter of the high-frequency band signal according to the energy attenuation value of the low-frequency band signal comprises:   attenuating the one of the group consisting of the high-frequency band signal and the to-be-encoded characteristic parameter of the high-frequency band signal according to the energy attenuation value and the signal class of the high-frequency band signal.   
     
     
         3 . The method according to  claim 2 , wherein
 the attenuating the one of the group consisting of the high-frequency band signal and the to-be-encoded characteristic parameter of the high-frequency band signal according to the energy attenuation value and the signal class of the high-frequency band signal comprises conditionally executing the following:   when the signal class of the high-frequency band signal is a transient class, attenuating a one of the group consisting of a high-frequency band time-domain signal and a to-be-encoded time domain envelope of the high-frequency band signal according to the energy attenuation value;   and,   when the signal class of the high-frequency band signal is a one of the group consisting of a fricative class, a harmonic class and a normal class, attenuating one of the group consisting of a high-frequency band frequency-domain signal and a to-be-encoded frequency domain envelope of the high-frequency band signal according to the energy attenuation value.   
     
     
         4 . The method according to  claim 1 , further comprising:
 encoding the low-frequency band signal and locally decoding a result of encoding the low-frequency band signal; and   using a ratio of energy of the low-frequency band signal to energy of a signal obtained by the locally decoding as the energy attenuation value.   
     
     
         5 . The method according to  claim 1 , wherein
 the energy attenuation value is a preset value, and the energy attenuation value is obtained according to ratios of energy of multiple low-frequency band signals of a same-class frame to energy of signals obtained by decoding encoding results of the low-frequency band signals of the same-class frame, wherein the same-class frame is a data frame of a same signal class as the high-frequency band signal of the current frame.   
     
     
         6 . A decoding method for processing speech/audio signals, comprising:
 decoding, by a decoder, a bit stream to obtain a one of the group consisting of (a) a high-frequency band signal of a current frame and (b) a characteristic parameter of the high-frequency band signal of the current frame, wherein the decoder comprises a processor; and   attenuating, by the decoder, the one of the group consisting of (a) the high-frequency band signal and (b) the characteristic parameter of the high-frequency band signal according to an energy attenuation value of a low-frequency band signal of the current frame, wherein the energy attenuation value indicates energy attenuation of the low-frequency band signal caused by encoding of the low-frequency band signal.   
     
     
         7 . The method according to  claim 6 , further comprising:
 decoding the bit stream to obtain a signal class of the high-frequency band signal of the current frame; and   wherein the attenuating the one of the group consisting of the high-frequency band signal and the characteristic parameter of the high-frequency band signal according to the energy attenuation value of the low-frequency band signal of the current frame comprises:   attenuating the one of the group consisting of the high-frequency band signal and the characteristic parameter of the high-frequency band signal according to the energy attenuation value and the signal class of the high-frequency band signal of the current frame.   
     
     
         8 . The method according to  claim 7 , wherein
 the attenuating the one of the group consisting of the high-frequency band signal and the characteristic parameter of the high-frequency band signal according to the energy attenuation value and the signal class of the high-frequency band signal of the current frame comprises conditionally executing the following:   when the signal class of the high-frequency band signal of the current frame is one of the group consisting of a transient class, attenuating a high-frequency band time-domain signal and a time-domain envelope of the high-frequency band signal according to the energy attenuation value;   and   when the signal class of the high-frequency band signal of the current frame is one of the group consisting of a fricative class, a harmonic class and a normal class, attenuating one of the group consisting of a high-frequency band frequency-domain signal and a frequency-domain envelope of the high-frequency band signal according to the energy attenuation value.   
     
     
         9 . The method according to  claim 6 , further comprising:
 decoding the bit stream to obtain the energy attenuation value, wherein the energy attenuation value indicates a ratio of energy of the low-frequency band signal of the current frame to energy of a signal obtained by locally decoding a result of encoding, by an encoder, the low-frequency band signal of the current frame.   
     
     
         10 . The method according to  claim 6 , wherein
 the energy attenuation value is a preset value, and the energy attenuation value is obtained according to a ratio of energy of a low-frequency band signal of a same-class frame to energy of a signal obtained by decoding a result of encoding the low-frequency band signal of the same-class frame, wherein the same-class frame is a data frame of a same signal class as the high-frequency band signal of the current frame.   
     
     
         11 . An encoding device for processing speech/audio signals, comprising:
 a processor;   a division unit controlled by the processor, configured to divide a current frame into a low-frequency band signal and a high-frequency band signal;   a correction unit controlled by the processor, configured to attenuate a one of the group consisting of the high-frequency band signal and a to-be-encoded characteristic parameter of the high-frequency band signal according to an energy attenuation value of the low-frequency band signal, wherein the energy attenuation value indicates energy attenuation of the low-frequency band signal caused by encoding of the low-frequency band signal of the current frame; and   an encoding unit controlled by the processor, configured to encode the one of the group consisting of the attenuated high-frequency band signal and the attenuated to-be-encoded characteristic parameter of the high-frequency band signal.   
     
     
         12 . The device according to  claim 11 , further comprising:
 a signal class determining unit, configured to determine a signal class of the high-frequency band signal;   wherein the correction unit is configured to attenuate the one of the group consisting of the high-frequency band signal and the to-be-encoded characteristic parameter of the high-frequency band signal according to the energy attenuation value and the signal class of the high-frequency band signal.   
     
     
         13 . The device according to  claim 12 , wherein the correction unit is configured to conditionally:
 attenuate the one of the group consisting of a high-frequency band time-domain signal and a to-be-encoded time domain envelope of the high-frequency band signal according to the energy attenuation value when the signal class of the high-frequency band signal is a transient class;   and   attenuate the one of the group consisting of a high-frequency band frequency-domain signal and a to-be-encoded frequency domain envelope of the high-frequency band signal according to the energy attenuation value when the signal class of the high-frequency band signal is one of the group consisting of a fricative class, a harmonic class and a normal class.   
     
     
         14 . The device according to  claim 11 , further comprises:
 an energy attenuation value obtaining unit configured to encode the low-frequency band signal and locally decode a result of encoding the low-frequency band signal, and use a ratio of energy of the low-frequency band signal to energy of a signal obtained by the local decoding as the energy attenuation value.   
     
     
         15 . The device according to  claim 11 , further comprises:
 an energy attenuation value setting unit configured to set the energy attenuation value, wherein the energy attenuation value is obtained according to ratios of energy of multiple low-frequency band signals of a same-class frame to energy of signals obtained by decoding results of encoding the low-frequency band signals of the same-class frame, wherein the same-class frame is a data frame of a same signal class as the high-frequency band signal of the current frame.   
     
     
         16 . A decoding device for processing speech/audio signals, comprising:
 a processor;   a decoding unit controlled by the processor, configured to decode a bit stream to obtain a one of the group consisting of a high-frequency band signal of a current frame and a characteristic parameter of the high-frequency band signal of the current frame; and   a correction unit controlled by the processor, configured to attenuate the one of the group consisting of the high-frequency band signal and the characteristic parameter of the high-frequency band signal according to an energy attenuation value of a low-frequency band signal of the current frame, wherein the energy attenuation value indicates energy attenuation of the low-frequency band signal caused by encoding of the low-frequency band signal of the current frame.   
     
     
         17 . The device according to  claim 16 , wherein
 the decoding unit is further configured to decode the bit stream to obtain a signal class of the high-frequency band signal of the current frame; and   the correction unit is configured to attenuate the one of the group consisting of the high-frequency band signal and the characteristic parameter of the high-frequency band signal according to the energy attenuation value and the signal class of the high-frequency band signal of the current frame.   
     
     
         18 . The device according to  claim 17 , wherein
 the correction unit is configured to conditionally execute the following:   attenuating one of the group consisting of a high-frequency band time-domain signal and a time-domain envelope of the high-frequency band signal according to the energy attenuation value when the signal class of the high-frequency band signal of the current frame is a transient class;   and   attenuating one of the group consisting of a high-frequency band frequency-domain signal and a frequency-domain envelope of the high-frequency band signal according to the energy attenuation value when the signal class of the high-frequency band signal of the current frame is one of the group consisting of a fricative class, a harmonic class and a normal class.   
     
     
         19 . The device according to  claim 16 , wherein
 the decoding unit is further configured to decode the bit stream to obtain the energy attenuation value, wherein the energy attenuation value indicates a ratio of energy of the low-frequency band signal of the current frame to energy of a signal obtained by locally decoding a result of encoding, by an encoder, the low-frequency band signal of the current frame.   
     
     
         20 . The device according to  claim 16 , further comprising:
 an energy attenuation value setting unit configured to set the energy attenuation value of the current frame, wherein the energy attenuation value is obtained according to a ratio of energy of a low-frequency band signal of a same-class frame to energy of a signal obtained by decoding a result of encoding the low-frequency band signal of the same-class frame, and the same-class frame is a data frame of a same signal class as the high-frequency band signal of the current frame.   
     
     
         21 . A signal classification method for processing speech/audio signals, comprising:
 dividing, by an encoder, a current frame into a low-frequency band signal and a high-frequency band signal, wherein the encoder comprises a processor;   determining, by the encoder, according to a value requirement of a preset encoding/decoding characteristic parameter corresponding to a signal class, whether an encoding/decoding characteristic parameter of the current frame corresponding to the signal class meets the value requirement of the encoding/decoding characteristic parameter; and   determining, by the encoder, a signal class of the high-frequency band signal of the current frame according to a determining result.   
     
     
         22 . The method according to  claim 21 , wherein
 the preset encoding/decoding characteristic parameter corresponding to the signal class comprises an encoding/decoding characteristic parameter corresponding to a noise class; and   the encoding/decoding characteristic parameter corresponding to the noise class is one of the group consisting of: a correlation parameter between an amplitude of a low-frequency band frequency-domain signal and an amplitude of a high-frequency band frequency-domain signal, and a correlation parameter between energy of the low-frequency band frequency-domain signal and energy of the high-frequency band frequency-domain signal.   
     
     
         23 . The method according to  claim 22 , further comprising:
 determining whether a number of sub-bands having a peak-to-average ratio smaller than a second threshold is greater than a second predetermined number; and   wherein the determining the signal class of the high-frequency band signal of the current frame comprises:   when the number of sub-bands having a peak-to-average ratio smaller than the second threshold is greater than the second predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the noise class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the noise class, determining that the signal class of the high-frequency band signal of the current frame is the noise class.   
     
     
         24 . The method according to  claim 21 , wherein
 the preset encoding/decoding characteristic parameter corresponding to the signal class comprises a one of the group consisting of an encoding/decoding characteristic parameter corresponding to a predicted class, and an encoding/decoding characteristic parameter corresponding to a harmonic class; and   the encoding/decoding characteristic parameter corresponding to the predicted class and the encoding/decoding characteristic parameter corresponding to the harmonic class are one of the group consisting of: a correlation parameter between a frequency-domain coefficient of the low-frequency band signal and a frequency-domain coefficient of the high-frequency band signal, a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band signal and an absolute value of the frequency-domain coefficient of the high-frequency band signal, a correlation parameter between a frequency-domain coefficient of a low-frequency band excitation spectrum and a frequency-domain coefficient of a high-frequency band excitation spectrum, and a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band excitation spectrum and an absolute value of the frequency-domain coefficient of the high-frequency band excitation spectrum.   
     
     
         25 . The method according to  claim 24 , further comprising:
 determining whether a number of sub-bands having a peak-to-average ratio greater than a first threshold is greater than a first predetermined number; and   when the preset encoding/decoding characteristic parameter corresponding to the signal class comprises the encoding/decoding characteristic parameter corresponding to the harmonic class, the determining the signal class of the high-frequency band signal of the current frame comprises:   when the number of sub-bands having a peak-to-average ratio greater than the first threshold is greater than the first predetermined number and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the harmonic class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the harmonic class, determining that the signal class of the high-frequency band signal of the current frame is the harmonic class.   
     
     
         26 . The method according to  claim 24 , further comprising:
 determining whether a number of sub-bands having a peak-to-average ratio greater than a first threshold is greater than a first predetermined number; and   when the preset encoding/decoding characteristic parameter corresponding to the signal class comprises the encoding/decoding characteristic parameter corresponding to the predicted class, the determining the signal class of the high-frequency band signal of the current frame comprises:   when the number of sub-bands having a peak-to-average ratio greater than the first threshold is not greater than the first predetermined number and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the predicted class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the predicted class, determining that the signal class of the high-frequency band signal of the current frame is the predicted class.   
     
     
         27 . The method according to  claim 21 , wherein
 the preset encoding/decoding characteristic parameter corresponding to the signal class further comprises an encoding/decoding characteristic parameter corresponding to a predicted class, and an encoding/decoding characteristic parameter corresponding to a harmonic class;   each of the encoding/decoding characteristic parameter corresponding to the predicted class and the encoding/decoding characteristic parameter corresponding to the harmonic class is one of the group consisting of: a correlation parameter between a frequency-domain coefficient of the low-frequency band signal and a frequency-domain coefficient of the high-frequency band signal, a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band signal and an absolute value of the frequency-domain coefficient of the high-frequency band signal, a correlation parameter between a frequency-domain coefficient of a low-frequency band excitation spectrum and a frequency-domain coefficient of a high-frequency band excitation spectrum, and a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band excitation spectrum and an absolute value of the frequency-domain coefficient of the high-frequency band excitation spectrum; and   the method further comprises determining whether a number of sub-bands having a peak-to-average ratio greater than a first threshold is greater than a first predetermined number; and determining whether the number of sub-bands having a peak-to-average ratio smaller than a second threshold is greater than a second predetermined number; and   wherein the determining the signal class of the high-frequency band signal of the current frame comprises conditionally executing the following:   when the number of sub-bands having a peak-to-average ratio greater than the first threshold is greater than the first predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the harmonic class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the harmonic class, determining that the signal class of the high-frequency band signal of the current frame is the harmonic class; and   when the number of sub-bands having a peak-to-average ratio greater than the first threshold is not greater than the first predetermined number, the number of sub-bands having a peak-to-average ratio smaller than the second threshold is not greater than the second predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the predicted class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the predicted class, determining that the signal class of the high-frequency band signal of the current frame is the predicted class.   
     
     
         28 . The method according to  claim 21 , further comprising:
 dividing a full-frequency time-domain signal of the current frame into N sub-frames, and when energy of one sub-frame is greater than a predetermined number of times of energy of a previous sub-frame of the sub-frame, determining that the signal class of the high-frequency band signal of the current frame is a transient class.   
     
     
         29 . A signal classification device for processing speech/audio signals, comprising:
 a processor;   a division unit controlled by the processor, configured to divide a current frame into a low-frequency band signal and a high-frequency band signal;   a judgment unit controlled by the processor, configured to determine, according to a value requirement of a preset encoding/decoding characteristic parameter corresponding to a signal class, whether an encoding/decoding characteristic parameter of the current frame corresponding to the signal class meets the value requirement of the encoding/decoding characteristic parameter; and   a determination unit controlled by the processor, configured to determine a signal class of the high-frequency band signal of the current frame according to a determining result.   
     
     
         30 . The device according to  claim 29 , wherein
 the preset encoding/decoding characteristic parameter corresponding to the signal class comprises an encoding/decoding characteristic parameter corresponding to a noise class; and   the encoding/decoding characteristic parameter corresponding to the noise class is one of the group consisting of: a correlation parameter between an amplitude of a low-frequency band frequency-domain signal and an amplitude of a high-frequency band frequency-domain signal, and a correlation parameter between energy of the low-frequency band frequency-domain signal and energy of the high-frequency band frequency-domain signal.   
     
     
         31 . The device according to  claim 30 , wherein
 the device further comprises a second peak-to-average ratio judgment unit, configured to determine whether a number of sub-bands having a peak-to-average ratio smaller than a second threshold in the high-frequency band signal of the current frame is greater than a second predetermined number; and   the determination unit comprises:   a noise class determining unit, configured to determine that the signal class of the high-frequency band signal of the current frame is the noise class, when the number of sub-bands having a peak-to-average ratio smaller than the second threshold is greater than the second predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the noise class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the noise class.   
     
     
         32 . The device according to  claim 29 , wherein
 the preset encoding/decoding characteristic parameter corresponding to the signal class comprises an encoding/decoding characteristic parameter corresponding to a predicted class, or an encoding/decoding characteristic parameter corresponding to a harmonic class; and   each of the encoding/decoding characteristic parameter corresponding to the predicted class and the encoding/decoding characteristic parameter corresponding to the harmonic class is one of the group consisting of: a correlation parameter between a frequency-domain coefficient of the low-frequency band signal and a frequency-domain coefficient of the high-frequency band signal, a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band signal and an absolute value of the frequency-domain coefficient of the high-frequency band signal, a correlation parameter between a frequency-domain coefficient of a low-frequency band excitation spectrum and a frequency-domain coefficient of a high-frequency band excitation spectrum, and a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band excitation spectrum and an absolute value of the frequency-domain coefficient of the high-frequency band excitation spectrum.   
     
     
         33 . The device according to  claim 29 , wherein
 the device further comprises a first peak-to-average ratio judgment unit, configured to determine whether a number of sub-bands having a peak-to-average ratio greater than a first threshold in the high-frequency band signal of the current frame is greater than a first predetermined number; and   when the preset encoding/decoding characteristic parameter corresponding to the signal class comprises the encoding/decoding characteristic parameter corresponding to a harmonic class, the determination unit comprises:   a harmonic class determining unit, configured to determine that the signal class of the high-frequency band signal of the current frame is the harmonic class, when the number of sub-bands having a peak-to-average ratio greater than the first threshold is greater than the first predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the harmonic class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the harmonic class.   
     
     
         34 . The device according to  claim 29 , wherein
 the device further comprises a first peak-to-average ratio judgment unit, configured to determine whether a number of sub-bands having a peak-to-average ratio greater than a first threshold in the high-frequency band signal of the current frame is greater than a first predetermined number; and   when the preset encoding/decoding characteristic parameter corresponding to the signal class comprises the encoding/decoding characteristic parameter corresponding to a predicted class, the determination unit comprises:   a predicted class determining unit, configured to determine that the signal class of the high-frequency band signal of the current frame is the predicted class, when the number of sub-bands having a peak-to-average ratio greater than the first threshold is not greater than the first predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the predicted class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the predicted class.   
     
     
         35 . The device according to  claim 29 , wherein
 the preset encoding/decoding characteristic parameter corresponding to the signal class comprises an encoding/decoding characteristic parameter corresponding to a predicted class, and an encoding/decoding characteristic parameter corresponding to a harmonic class;   each of the encoding/decoding characteristic parameter corresponding to the predicted class and the encoding/decoding characteristic parameter corresponding to the harmonic class is one of the group consisting of: a correlation parameter between a frequency-domain coefficient of the low-frequency band signal and a frequency-domain coefficient of the high-frequency band signal, a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band signal and an absolute value of the frequency-domain coefficient of the high-frequency band signal, a correlation parameter between a frequency-domain coefficient of a low-frequency band excitation spectrum and a frequency-domain coefficient of a high-frequency band excitation spectrum, and a correlation parameter between an absolute value of the frequency-domain coefficient of the low-frequency band excitation spectrum and an absolute value of the frequency-domain coefficient of the high-frequency band excitation spectrum;   the device further comprises a first peak-to-average ratio judgment unit, configured to determine whether a number of sub-bands having a peak-to-average ratio greater than a first threshold in the high-frequency band signal of the current frame is greater than a first predetermined number; and a second peak-to-average ratio judgment unit, configured to determine whether the number of sub-bands having a peak-to-average ratio smaller than a second threshold in the high-frequency band signal of the current frame is greater than a second predetermined number; and   the determination unit comprises:   a harmonic class determining unit, configured to determine that the signal class of the high-frequency band signal of the current frame is the harmonic class, when the number of sub-bands having a peak-to-average ratio greater than the first threshold is greater than the first predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the harmonic class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the harmonic class; and   a predicted class determining unit, configured to determine that the signal class of the high-frequency band signal of the current frame is the predicted class, when the number of sub-bands having a peak-to-average ratio greater than the first threshold is greater than the first predetermined number, the number of sub-bands having a peak-to-average ratio smaller than the second threshold is not greater than the second predetermined number, and a value of the encoding/decoding characteristic parameter of the current frame corresponding to the predicted class meets the value requirement of the preset encoding/decoding characteristic parameter corresponding to the predicted class.   
     
     
         36 . The device according to  claim 29 , wherein
 the device further comprises:   a transient class determining unit, configured to divide a full-frequency band time-domain signal of the current frame into N sub-frames, and when energy of one sub-frame is greater than a predetermined number of times of energy of a previous sub-frame of the sub-frame, determine that the signal class of the high-frequency band signal of the current frame is a transient class.