AlgebraicCodebookSearchL1_G7291, AlgebraicCodebookSearchL2_G7291

Performs the fixed (algebraic) codebook search.

Syntax

IppStatus ippsAlgebraicCodebookSearchL1_G7291_16s(const Ipp16s pSrcFixedTarget[40], const Ipp16s pSrcLtpResidual[40], const Ipp16s pSrcFltAdptVector[40], Ipp16s pSrcDstImpulseResponse[40], Ipp16s pitchLag, Ipp16s pitchGain, Ipp16s pDstFixedVector[40], Ipp16s pDstFltFixedVector[40], Ipp16s pDstCodebookIdx[2]);

IppStatus ippsAlgebraicCodebookSearchL2_G7291_16s(const Ipp16s pSrcFixedTarget[40], const Ipp16s pSrcLtpResidual[40], Ipp16s pSrcDstImpulseResponse[40], Ipp16s voiceFactor, Ipp16s pDstFixedVector[40], Ipp16s pDstFltFixedVector[40], Ipp16s pDstCodebookIdx[2]);

Parameters

pSrcFixedTarget

Pointer to the input updated target speech vector.

pSrcLtpResidual

Pointer to the input residual vector after long term prediction.

pSrcFltAdptFixedVector

Pointer to the input filtered adaptive fixed-codebook vector.

pSrcDstImpulseResponse

Pointer to the output LP synthesis filter.

pitchLag

Value of the pitch lag.

pitchGain

Gain value of the last quantized pitch.

pDstFixedVector

Pointer to the fixed-codebook vector.

pDstFltFixedVector

Pointer to the output filtered fixed-codebook vector.

pDstCodebookIndex

Pointer to the fixed-codebook index.

voiceFactor

Voicing factor value.

Description

The functions ippsAlgebraicCodebookSearchL1_G7291 and ippsAlgebraicCodebookSearchL2_G7291 are declared in the ippsc.h file. The ippsAlgebraicCodebookSearchL1_ G7291 function searches the fixed-codebook vector and index at 8 kbps rate similar to the G.729 fixed-codebook search. The difference is that for some parts this function uses the orthogonal search procedure and global pulse replacement method described in [ITU7291] section 6.3.7.

The ippsAlgebraicCodebookSearchL2_G7291 function searches the fixed-codebook vector and index at 12 kbps. The 12 kbit/s enhancement layer relies on the extra fixed codebook; that, when combined with the 8 kbit/s core layer excitation, offers a richer excitation signal. In particular this extra fixed codebook better represents high frequencies of the LP excitation. This benefit is increased by the use of a modified perceptual filter to stress high frequencies. See more details in [ITU7291] section 6.3.9.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error when one of the specified pointers is NULL.

ippStsRangeErr

Indicates an error when pitchLag is less than 19 or greater than 144.

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