Preemphasize

Computes pre-emphasis of a speech signal.

Syntax

IppStatus ippsPreemphasize_GSMFR_16s(const Ipp16s* pSrc, Ipp16s* pDst, int* pMem, int len);

Parameters

pSrc	Pointer to the offset-free input speech signal.
pDst	Pointer to the pre-emphasized output signal.
pMem	Pointer to the filter memory value.
len	Length of the input and output signals.

Description

The function ippsPreemphasize_GSMFR is declared in ippsc.h file. This function computes pre-emphasis of the input speech according to the difference signal pre-emphasis equation:

H(z) = 1 - γ*z^-1

for γ = -0.86 and pSrc[-1] = pMem[0].

The result of filtering is stored in pDst. The memory value pMem[0] is updated by pSrc[n-1]. For proper use of this function in GSM Full Rate codec, the memory value will be initialized to zero.

The function ippsPreemphasize_GSMFR performs NR rounding (see Rounding mode ).

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when one of the specified pointer is NULL.
ippStsSizeErr	Indicates an error when len is less than or equal to 0.