Audio coding method and apparatus
First Claim
1. An audio coding method comprising:
- obtaining an audio signal;
performing linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal;
determining a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition, wherein determining the first modification weight according to LSF differences of the current frame and LSF differences of the previous frame of the current frame of the audio signal comprises determining the first modification weight according to the LSF differences of the current frame and the LSF differences of the previous frame according to
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Abstract
An audio coding method and apparatus, where the method includes, for each audio frame in audio, when a signal characteristic of the audio frame and a signal characteristic of a previous audio frame meet a preset modification condition, determining a first modification weight according to linear spectral frequency (LSF) differences of the audio frame and LSF differences of the previous audio frame, modifying a linear predictive parameter of the audio frame according to the determined first modification weight, and coding the audio frame according to a modified linear predictive parameter of the audio frame. According to the present disclosure, audio having a wider bandwidth can be coded while a bit rate remains unchanged or a bit rate slightly changes and a spectrum between audio frames is steadier.
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Citations
25 Claims
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1. An audio coding method comprising:
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obtaining an audio signal; performing linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal; determining a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition, wherein determining the first modification weight according to LSF differences of the current frame and LSF differences of the previous frame of the current frame of the audio signal comprises determining the first modification weight according to the LSF differences of the current frame and the LSF differences of the previous frame according to - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An audio coding apparatus comprising:
a processor configured to; obtain an audio signal; perform linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal; determine a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition, wherein the processor is further configured to determine the first modification weight according to the LSF differences of the current frame and the LSF differences of the previous frame according to - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An audio coding apparatus comprising:
a processor configured to; obtain an audio signal; perform linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal; determine a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition; modify the linear predictive parameter of the current frame according to the first modification weight; code the current frame according to the modified linear predictive parameter; determine the first modification weight according to the LSF differences of the current frame and the LSF differences of the previous frame when the current frame is not a transition frame; determine the first modification weight according to the LSF differences of the current frame and the LSF differences of the previous frame when a spectrum tilt frequency of the previous frame is not greater than a first spectrum tilt frequency threshold or a spectrum tilt frequency of the current frame is not less than a second spectrum tilt frequency threshold; and determine a second modification weight when the spectrum tilt frequency of the previous frame is greater than the first spectrum tilt frequency threshold and the spectrum tilt frequency of the current frame is less than the second spectrum tilt frequency threshold.
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22. An audio coding apparatus comprising:
a processor configured to; obtain an audio signal; perform linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal; determine a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition; modify the linear predictive parameter of the current frame according to the first modification weight; code the current frame according to the modified linear predictive parameter; determine the first modification weight according to the LSF differences of the current frame and the LSF differences of the previous frame when the current frame is not a transition frame; determine the first modification weight according to the LSF differences of the current frame and the LSF differences of the previous frame when a spectrum tilt frequency of the previous frame is not less than a first spectrum tilt frequency threshold, or a coding type of the previous frame is not one of voiced, generic, transient, or audio, or a spectrum tilt of the current frame is not greater than a second spectrum tilt frequency threshold; and determine a second modification weight when the spectrum tilt frequency of the previous frame is less than the first spectrum tilt frequency threshold, the coding type of the previous frame is one of voiced, generic, transient, or audio, and the spectrum tilt frequency of the current frame is greater than the second spectrum tilt frequency threshold.
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23. An audio coding method comprising:
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obtaining an audio signal; performing linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal; determining a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition; modifying the linear predictive parameter of the current frame according to the determined first modification weight; and coding the current frame according to the modified linear predictive parameter, wherein the signal characteristic of the current frame and the signal characteristic of the previous frame meet a preset modification condition when the current frame is not a transition frame, wherein the transition frame comprises a transition from a non-fricative to a fricative or a transition from the fricative to the non-fricative, and wherein the current frame is the transition frame from the fricative to the non-fricative when a spectrum tilt frequency of the previous frame is greater than a first spectrum tilt frequency threshold and a coding type of the current frame is transient.
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24. An audio coding method comprising:
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obtaining an audio signal; performing linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal; determining a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition; modifying the linear predictive parameter of the current frame according to the determined first modification weight; and coding the current frame according to the modified linear predictive parameter, wherein the signal characteristic of the current frame and the signal characteristic of the previous frame meet a preset modification condition when the current frame is not a transition frame, wherein the transition frame comprises a transition from a non-fricative to a fricative or a transition from the fricative to the non-fricative, and wherein the current frame is the transition frame from the fricative to the non-fricative when a spectrum tilt frequency of the previous frame is greater than a first spectrum tilt frequency threshold and the spectrum tilt frequency of the current frame is less than a second spectrum tilt frequency threshold.
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25. An audio coding method comprising:
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obtaining an audio signal; performing linear prediction analysis on the audio signal to obtain a linear predictive parameter of a current frame of the audio signal; determining a first modification weight according to linear spectral frequency (LSF) differences of the current frame of the audio signal and LSF differences of a previous frame of the current frame of the audio signal, when a signal characteristic of the current frame and a signal characteristic of the previous frame meet a preset modification condition; modifying the linear predictive parameter of the current frame according to the determined first modification weight; and coding the current frame according to the modified linear predictive parameter, wherein the signal characteristic of the current frame and the signal characteristic of the previous frame meet a preset modification condition when the current frame is not a transition frame, wherein the transition frame comprises a transition from a non-fricative to a fricative or a transition from the fricative to the non-fricative, wherein the current frame is the transition frame from the non-fricative to the fricative when a spectrum tilt frequency of the previous frame is less than a first spectrum tilt frequency threshold, wherein a coding type of the previous frame is one of voiced, generic, transient, or audio, and wherein the spectrum tilt frequency of the current frame is greater than a second spectrum tilt frequency threshold.
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Specification