Directly filters a source vector through a single-rate FIR filter.
Syntax
Case 1: Not-in-place operation on integer samples
IppStatus ippsFIR_Direct_16s_Sfs(const Ipp16s* pSrc, Ipp16s* pDst, int numIters, const Ipp16s* pTapsQ15, int tapsLen, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32f_Direct_16s_Sfs(const Ipp16s* pSrc, Ipp16s* pDst, int numIters, const Ipp32f* pTaps, int tapsLen, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64f_Direct_16s_Sfs(const Ipp16s* pSrc, Ipp16s* pDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64f_Direct_32s_Sfs(const Ipp32s* pSrc, Ipp32s* pDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp32s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32fc_Direct_16sc_Sfs(const Ipp16sc* pSrc, Ipp16sc* pDst, int numIters, const Ipp32fc* pTaps, int tapsLen, Ipp16sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64fc_Direct_16sc_Sfs(const Ipp16sc* pSrc, Ipp16sc* pDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp16sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64fc_Direct_32sc_Sfs(const Ipp32sc* pSrc, Ipp32sc* pDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp32sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32s_Direct_16s_Sfs(const Ipp16s* pSrc, Ipp16s* pDst, int numIters, const Ipp32s* pTaps, int tapsLen, int tapsFactor, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32sc_Direct_16sc_Sfs(const Ipp16sc* pSrc, Ipp16sc* pDst, int numIters, const Ipp32sc* pTaps, int tapsLen, int tapsFactor, Ipp16sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
Case 2: Not-in-place operation on floating point samples
IppStatus ippsFIR_Direct_32f(const Ipp32f* pSrc, Ipp32f* pDst, int numIters, const Ipp32f* pTaps, int tapsLen, Ipp32f* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR_Direct_64f(const Ipp64f* pSrc, Ipp64f* pDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp64f* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR_Direct_32fc(const Ipp32fc* pSrc, Ipp32fc* pDst, int numIters, const Ipp32fc* pTaps, int tapsLen, Ipp32fc* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR_Direct_64fc(const Ipp64fc* pSrc, Ipp64fc* pDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp64fc* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR64f_Direct_32f(const Ipp32f* pSrc, Ipp32f* pDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp32f* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR64fc_Direct_32fc(const Ipp32fc* pSrc, Ipp32fc* pDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp32fc* pDlyLine, int* pDlyLineIndex);
Case 3: In-place operation on integer samples
IppStatus ippsFIR_Direct_16s_ISfs(Ipp16s* pSrcDst, int numIters, const Ipp16s* pTapsQ15, int tapsLen, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32f_Direct_16s_ISfs(Ipp16s* pSrcDst, int numIters, const Ipp32f* pTaps, int tapsLen, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64f_Direct_16s_ISfs(Ipp16s* pSrcDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64f_Direct_32s_ISfs(Ipp32s* pSrcDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp32s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32fc_Direct_16sc_ISfs(Ipp16sc* pSrcDst, int numIters, const Ipp32fc* pTaps, int tapsLen, Ipp16sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64fc_Direct_16sc_ISfs(Ipp16sc* pSrcDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp16sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR64fc_Direct_32sc_ISfs(Ipp32sc* pSrcDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp32sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32s_Direct_16s_ISfs(Ipp16s* pSrcDst, int numIters, const Ipp32s* pTaps, int tapsLen, int tapsFactor, Ipp16s* pDlyLine, int* pDlyLineIndex, int scaleFactor);
IppStatus ippsFIR32sc_Direct_16sc_ISfs(Ipp16sc* pSrcDst, int numIters, const Ipp32sc* pTaps, int tapsLen, int tapsFactor, Ipp16sc* pDlyLine, int* pDlyLineIndex, int scaleFactor);
Case 4: In-place operation on floating point samples
IppStatus ippsFIR_Direct_32f_I(Ipp32f* pSrcDst, int numIters, const Ipp32f* pTaps, int tapsLen, Ipp32f* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR_Direct_64f_I(Ipp64f* pSrcDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp64f* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR_Direct_32fc_I(Ipp32fc* pSrcDst, int numIters, const Ipp32fc* pTaps, int tapsLen, Ipp32fc* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR_Direct_64fc_I(Ipp64fc* pSrcDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp64fc* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR64f_Direct_32f_I(Ipp32f* pSrcDst, int numIters, const Ipp64f* pTaps, int tapsLen, Ipp32f* pDlyLine, int* pDlyLineIndex);
IppStatus ippsFIR64fc_Direct_32fc_I(Ipp32fc* pSrcDst, int numIters, const Ipp64fc* pTaps, int tapsLen, Ipp32fc* pDlyLine, int* pDlyLineIndex);
Parameters
pSrc |
Pointer to the source vector. |
pDst |
Pointer to the output array. |
pSrcDst |
Pointer to the source and destination vector for the in-place operation. |
numIters |
Number of iterations. |
pTaps |
Pointer to the array containing the tap values. The number of elements in the array is tapsLen. |
pTapsQ15 |
Pointer to the array containing the tap values, represented in Q0.15 format. The number of elements in the array is tapsLen. |
tapsLen |
Number of elements in the array containing the tap values. |
tapsFactor |
Scale factor for the integer taps. |
pDlyLine |
Pointer to the array containing the delay line values. The number of elements in the array is 2*tapsLen. Note that the delay line length is different than that for FIR filters using state structure. |
pDlyLineIndex |
Pointer to the current delay line index. |
scaleFactor |
Scale factor, refer to Integer Scaling. |
Description
The function ippsFIR_Direct is declared in the ipps.h file. This function filters an source vector pSrc or pSrcDst containing numIters samples through a single-rate filter, and stores the resulting numIters samples in pDst or pSrcDst, respectively. The results are identical to numIters consecutive calls to ippsFIROne_Direct. The values of filter coefficients (taps) are specified in the tapsLen-length array pTaps. To scale integer taps the tapsFactor value is used. The set of tapsLen input samples is copied to the 2*tapsLen-length array pDlyLine. Double length of the delay line in direct FIR filters is used to improve filter performance by decreasing the number of sample copyings. The current delay line index is specified in the pDlyLineIndex. The output of the integer sample is scaled according to scaleFactor and can be saturated.
In the following definition of the FIR filter, the sample to be filtered is denoted x(n), the taps are denoted h(i), and the return value is y(n).
The return value y(n) is defined by the formula for a single-rate filter:
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when one of the specified pointers is NULL. |
ippStsFIRLenErr |
Indicates an error when tapsLen is less than or equal to 0. |
ippStsSizeErr |
Indicates an error when numIters is less than or equal to 0. |