AdaptiveCodebookSearch

Performs the adaptive codebook search.

Syntax

IppStatus ippsAdaptiveCodebookSearch_GSMAMR_16s(const Ipp16s* pSrcTarget, const Ipp16s* pSrcImpulseResponse, Ipp16s* pSrcOpenLoopLag, Ipp16s* pValResultPrevIntPitchLag, Ipp16s* pSrcDstExcitation, Ipp16s* pResultFracPitchLag, Ipp16s* pResultAdptIndex, Ipp16s* pDstAdptVector, Ipp16s subFrame, IppSpchBitRate mode);

Parameters

pSrcTarget	Pointer to the 40-element adaptive target signal vector, represented using Q15.0. This should be aligned on an 8‑byte boundary.
pSrcImpulseResponse	Pointer to the 40-element impulse response of the weighted synthesis filter, represented using Q3.12. This should be aligned on an 8‑byte boundary.
pSrcOpenLoopLag	Pointer to a two-element vector of OLP lags. For 5.15 and 4.75 kbps frames, only the first vector element contains a valid lag value, since only one lag is estimated. For all other bit rates, both vector elements contain valid pitch lag values.
pValResultPrevIntPitchLag	Pointer to the previous integral pitch lag.
pSrcDstExcitation	Pointer to the 194-element excitation vector. Elements 0 ~ 153 contain the past excitation, represented using Q15.0. Elements 154 ~ 193 are used as a buffer whenever the subframe length exceeds the pitch lag. On output, elements 154 - 193 are updated to contain the adaptive codebook vector.
pResultFracPitchLag	Pointer to the fractional pitch lag obtained during the adaptive codebook search.
pResultAdptIndex	Pointer to the coded closed-loop pitch index.
pDstAdptVector	Pointer to the 40-sample adaptive codebook vector, represented using Q15.0.
subFrame	Subframe index.
mode	Bit rate specifier. Values between IPP_SPCHBR_4750 and IPP_SPCHBR_12200 are valid.

Description

The function ippsAdaptiveCodebookSearch_GSMAMR is declared in ippsc.h file. This function performs the adaptive codebook search. The adaptive codebook search consists of a closed-loop pitch search followed by computation of an adaptive excitation vector. The adaptive excitation vector is obtained by interpolating the past excitation at the fractional pitch lag obtained during the closed-loop pitch search. The adaptive codebook is searched on every subframe.

Return Values

ippStsNoErr	Indicates no error.
IppStsNullPtrErr	Indicates an error when one of the specified pointers is NULL.
ippStsRangeErr	Indicates an error when mode is not a valid element of the enumerated type IppSpchBitRate.
ippStsSizeErr	Indicates an error when subFrame is not in the range [0, 3].