LongTermReconstruct

Uses Long Term Reconstruct (LTR) to reduce signal redundancy between successive coding frames.

Syntax

IppStatus ippsLongTermReconstruct_AAC_32s(Ipp32s* pSrcEstSpec, Ipp32s* pSrcDstSpec, int* pLtpFlag, int winSequence, int samplingFreqIndex);

Parameters

pSrcDstSpec	Pointer to spectral coefficients for LTP.
pSrcEstSpec	Pointer to the frequency domain vector.
winSequence	Window type, long or short.
samplingFreqIndex	Sampling frequency index.
pLtpFlag	Pointer to the LTP flag.

Description

This function is declared in the ippac.h file. The function uses Long Term Reconstruct (LTP) to reduce signal redundancy between successive coding frames.

LTP is a forward adaptive predictor that is inherently less sensitive to the round-off numerical errors in the decoder or bi-errors in the transmitted spectral coefficients.

You should add the vector of decoded spectral coefficients and the corresponding frequency domain vector to get the vector of reconstructed spectral coefficients.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when at least one of the specified pointers is NULL.
ippStsAacSmplRateIdxErr	Indicates an error when samplingFreqIndex exceeds [0,12].
ippStsAacWinSeqErr	Indicates an error when winSequence exceeds [0,3].