TiltCompensation

Compensates for the tilt in the short-term filter.

Syntax

IppStatus ippsTiltCompensation_G729_16s(const Ipp16s* pSrcImpulseResponse, Ipp16s* pSrcDstSpch);

IppStatus ippsTiltCompensation_G729A_16s(const Ipp16s* pSrcLPC, Ipp16s* pSrcDstFltResidual);

IppStatus ippsTiltCompensation_G729E_16s(Ipp16s val, const Ipp16s* pSrc, Ipp16s* pDst);

Parameters

pSrcImpulseResponse	Pointer to the impulse response `h`_f(n) vector [20], in Q12.
pSrcLPC	Pointer to the gamma weighted LP coefficients vector [22], in Q12. The first 11 elements refer to `γ`_n and the next 11 elements refer to `γ`_d.
pSrcDstSpch	Pointer to the present and tilt-compensated speech x(n), in Q15. Elements pSrcDstSpch[0...39] are the present speech signals, element pSrcDstSpch[-1] is the history that will be used.
pSrcDstFltResidual	Pointer to the long-term filtered LP residual, in Q15. Elements pSrcDstFltResidual[0...39] are the present long-term filtered LP residual signals, element pSrcDstFltResidual[-1] is the history that will be used.
val	The input tilt factor.
pSrc	Pointer to the source vector [41].
pDst	Pointer to the output filtered residual vector [40]

Description

These functions are declared in the ippsc.h file. These FIR filters compensate for the tilt in the short-term filter. They are applied in subframes.

The function ippsTiltCompensation_G729 is designed for G.729/B codec [ITU729, ITU729B].

The function ippsTiltCompensation_G729E is similar but it does not calculate the tilt factor and performs the operation for a given input tilt factor val and filter memory specified by pSrc[0].

The function ippsTiltCompensation_G729A is designed for G.729A codec [ITU729A].

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when one of the specified pointers is NULL.