Speech decoder with high-band generation and temporal envelope shaping

A speech decoding device for decoding an encoded speech signal, the speech decoding device comprising:

• a processor;
• a bit stream separating unit executable by the processor to separate a bit stream that includes the encoded speech signal into an encoded bit stream and temporal envelope supplementary information, the bit stream received from outside the speech decoding device;
• a core decoding unit executable by the processor to decode the encoded bit stream to obtain a low frequency component;
• a frequency transform unit executable by the processor to transform the low frequency component into a frequency domain;
• a high frequency generating unit executable by the processor to generate a high frequency component by copying the low frequency component from a low frequency band to a high frequency band;
• a high frequency adjusting unit executable by the processor to adjust the high frequency component generated by the high frequency generating unit to generate an adjusted high frequency component;
• a low frequency temporal envelope analysis unit executable by the processor to analyze the low frequency component transformed into the frequency domain by the frequency transform unit to obtain temporal envelope information, the low frequency temporal envelope analysis unit executable to obtain the temporal envelope information by obtaining power of each quadrature mirror filter (QMF) subband sample of the low frequency component transformed into the frequency domain by the frequency transform unit;
• supplementary information converting unit executable by the processor to convert the temporal envelope supplementary information into a parameter for adjustment of the temporal envelope information;
• a temporal envelope adjusting unit executable by the processor to adjust the temporal envelope information obtained by the low frequency temporal envelope analysis unit to generate adjusted temporal envelope information, the temporal envelope adjusting unit executable to use the parameter to adjust the temporal envelope information;
• and
• a temporal envelope shaping unit executable to shape a temporal envelope of the adjusted high frequency component using the adjusted temporal envelope information.

A speech decoding device for decoding an encoded speech signal, the speech decoding device comprising:

• a processor;
• a core decoding unit executable to decode a bit stream that includes the encoded speech signal to obtain a low frequency component, the bit stream received from outside the speech decoding device;
• a frequency transform unit executable by the processor to transform the low frequency component into a frequency domain;
• a high frequency generating unit executable by the processor to generate a high frequency component by copying the low frequency component from a low frequency band to a high frequency band;
• a high frequency adjusting unit executable with the processor to adjust the high frequency component to generate an adjusted high frequency component;
• a low frequency temporal envelope analysis unit executable by the processor to analyze the low frequency component transformed into the frequency domain by the frequency transform unit to obtain temporal envelope information, the low frequency temporal envelope analysis unit executable to obtain the temporal envelope information by obtaining a power value of each quadrature mirror filter (QMF) subband sample of the low frequency component transformed into the frequency domain by the frequency transform unit;
• a temporal envelope supplementary information generating unit executable by the processor to analyze the bit stream to generate a parameter for adjustment of the temporal envelope information;
• a temporal envelope adjusting unit executable by the processor to adjust the temporal envelope information to generate adjusted temporal envelope information, the temporal envelope adjusting unit executable to use the parameter to adjust the temporal envelope information;
• and
• a temporal envelope shaping unit executable by the processor to shape a temporal envelope of the adjusted high frequency component using the adjusted temporal envelope information.

A speech decoding method using a speech decoding device for decoding an encoded speech signal, the speech decoding method comprising:

• a bit stream separating step in which the speech decoding device separates a bit stream that includes the encoded speech signal into an encoded bit stream and temporal envelope supplementary information, the bit stream received from outside the speech decoding device;
• a core decoding step in which the speech decoding device obtains a low frequency component by decoding the encoded bit stream separated in the bit stream separating step;
• a frequency transform step in which the speech decoding device transforms the low frequency component obtained in the core decoding step into a frequency domain;
• a high frequency generating step in which the speech decoding device generates a high frequency component by copying the low frequency component transformed into the frequency domain in the frequency transform step from a low frequency band to a high frequency band;
• a high frequency adjusting step in which the speech decoding device adjusts the high frequency component generated in the high frequency generating step to generate an adjusted high frequency component;
• a low frequency temporal envelope analysis step in which the speech decoding device obtains temporal envelope information by analyzing the low frequency component transformed into the frequency domain in the frequency transform step, wherein the temporal envelope information is obtained by obtaining a power of each quadrature mirror filter (QMF) subband sample of the low frequency component transformed into the frequency domain in the frequency transform step;
• a supplementary information converting step in which the speech decoding device converts the temporal envelope supplementary information into a parameter for adjusting the temporal envelope information;
• a temporal envelope adjusting step in which the speech decoding device adjusts the temporal envelope information obtained in the low frequency temporal envelope analysis step to generate adjusted temporal envelope information, wherein the parameter is utilized in said adjusting of the temporal envelope information;
• and
• a temporal envelope shaping step in which the speech decoding device shapes a temporal envelope of the adjusted high frequency component using the adjusted temporal envelope information.

A speech decoding method using a speech decoding device for decoding an encoded speech signal, the speech decoding method comprising:

• a core decoding step in which the speech decoding device decodes a bit stream that includes the encoded speech signal to obtain a low frequency component, the bit stream received from outside the speech decoding device a frequency transform step in which the speech decoding device transforms the low frequency component obtained in the core decoding step into a frequency domain;
• a high frequency generating step in which the speech decoding device generates a high frequency component by copying the low frequency component transformed into the frequency domain in the frequency transform step from a low frequency band to a high frequency band;
• a high frequency adjusting step in which the speech decoding device adjusts the high frequency component generated in the high frequency generating step to generate an adjusted high frequency component;
• a low frequency temporal envelope analysis step in which the speech decoding device obtains temporal envelope information by analyzing the low frequency component transformed into the frequency domain in the frequency transform step, wherein the temporal envelope information is obtained by obtaining a power value of each quadrature mirror filter (QMF) subband sample of the low frequency component transformed into the frequency domain in the frequency transform step;
• a temporal envelope supplementary information generating step in which the speech decoding device analyzes the bit stream to generate a parameter for adjusting the temporal envelope information;
• a temporal envelope adjusting step in which the speech decoding device adjusts the temporal envelope information obtained in the low frequency temporal envelope analysis step to generate adjusted temporal envelope information, wherein the parameter is utilized in said adjusting of the temporal envelope information;
• and
• a temporal envelope shaping step in which the speech decoding device shapes a temporal envelope of the adjusted high frequency component using the adjusted temporal envelope information.

A non-transitory storage medium that stores instructions executable by a processor to decode an encoded speech signal, the storage medium comprising:

• instructions executable by the processor to separate a bit stream that includes the encoded speech signal into an encoded bit stream and temporal envelope supplementary information;
• instructions executable by the processor to decode the encoded bit stream to obtain a low frequency component;
• instructions executable by the processor to transform the low frequency component into a frequency domain;
• instructions executable by the processor to generate a high frequency component by copying the low frequency component transformed into the frequency domain from a low frequency band to a high frequency band;
• instructions executable by the processor to adjust the high frequency component to generate an adjusted high frequency component;
• instructions executable by the processor to analyze the low frequency component transformed into the frequency domain to obtain temporal envelope information by determination of a power of each quadrature mirror filter (QMF) subband sample of the low frequency component transformed into the frequency domain by the frequency transform means;
• instructions executable by the processor to convert the temporal envelope supplementary information into a parameter for adjusting the temporal envelope information;
• instructions executable by the processor to adjust the temporal envelope information to generate adjusted temporal envelope information using the parameter;
• and
• instructions executable by the processor to shape a temporal envelope of the adjusted high frequency component using the adjusted temporal envelope information.

A non-transitory storage medium that stores instructions executable by a processor to decode an encoded speech signal, the storage medium comprising:

• instructions executable by the processor to decode a bit stream that includes the encoded speech signal to obtain a low frequency component;
• instructions executable by the processor to transform the low frequency component into a frequency domain;
• instructions executable by the processor to generate a high frequency component by copying the low frequency component transformed into the frequency domain from a low frequency band to a high frequency band;
• instructions executable by the processor to adjust the high frequency component to generate an adjusted high frequency component;
• instructions executable by the processor to analyze the low frequency component transformed into the frequency domain to obtain temporal envelope information by determination of a power value of each QMF subband sample of the low frequency component transformed into the frequency domain;
• instructions executable by the processor to analyze the bit stream to generate a parameter for adjustment of the temporal envelope information;
• instructions executable by the processor to adjust the temporal envelope information to generate adjusted temporal envelope information using the parameter;
• and
• instructions executable by the processor to shape a temporal envelope of the adjusted high frequency component using the adjusted temporal envelope information.