PostFilterLowBand_AMRWBE

Post-processes the low-band decoded signal.

Syntax

IppStatus ippsPostFilterLowBand_AMRWBE_16s(const Ipp16s* pSrcOldPitchLag, const Ipp16s* pSrcOldPitchGain, Ipp16s* pSrcDstSignal, Ipp16s* pOldSynth, Ipp16s* pOldNoise, Ipp16s* pFilterScale, Ipp32s pitchAdjust);

Parameters

pSrcOldPitchLag

Pointer to the previous pitch periods for all subframes [16]

pSrcOldPitchGain

Pointer to the previous pitch gains for all subframes [16]

pSrcDstSignal

Pointer to the proceeding signal [1024].

pOldSynth

Pointer to the synthesis memory of post-filter [503].

pOldNoise

Pointer to the noise memory of post-filter [24].

pFilterScale

Pointer to the noise memory of post-filter scale factor.

pitchAdjust

Pitch adjustment flag, if it is NULL, then pitch adjustment is not implemented.

Description

The function ippsPostFilterLowBand_AMRWBE is declared in ippsc.h file. The decoded signal is first processed by an adaptive pitch enhancer, and then filtered through a long-term prediction filter. Then the obtained long term error signal is low-pass filtered and subtracted from the input signal.

See also 3GPP TS 26.290: “Extended AMR Wideband Speech Codec; Transcoding functions", clauses 6.1.3 [AMRWB+].

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

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

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