CPC G10L 19/03 (2013.01) [G10L 19/12 (2013.01); G10L 19/26 (2013.01); G10L 19/265 (2013.01); G10L 21/038 (2013.01); G10L 2019/0016 (2013.01); G10L 19/0204 (2013.01)] | 14 Claims |
1. An encoding method, comprising:
dividing an input time domain signal into a low band signal and a high band signal;
encoding, using an algebraic code excited linear prediction (ACELP) encoder, the low band signal to obtain a low frequency encoding parameter;
obtaining an excitation signal according to the low frequency encoding parameter;
encoding the high band signal to obtain a high frequency encoding parameter;
obtaining, by passing the excitation signal through a linear predictive coding (LPC) synthesis filter, a synthesized high band signal, wherein coefficients of the LPC synthesis filter are based on the high frequency encoding parameter;
performing, using a short-term post-filter, filtering processing on the synthesized high band signal to obtain a short-time filtered signal, wherein the short-term post-filter comprises a pole-zero filter, and wherein a coefficient of the pole-zero filter is based on the high frequency encoding parameter;
calculating a z-domain transfer function of the pole-zero filter using the following formula:
![]() wherein Hs(z) is the z-domain transfer function, wherein a1, a2, . . . aM is an LPC coefficient, wherein M represents a quantity of the LPC coefficient, and wherein β and γ are constants that satisfy a condition 0<β<γ<1; and
calculating a high frequency gain based on the high band signal and the short-time filtered signal.
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