ResamplePolyphase

Upsamples or downsamples the input signal to or from the upper frequency (44.1/48 khz).

Syntax

IppStatus ippsResamplePolyphase_AMRWBE_16s(const Ipp16s* pSrcSignal, int lenSrc, Ipp16s upFactor, Ipp16s downFactor, Ipp16s* pInterpFracMem, Ipp16s* pMem, Ipp16s* pDstSignal, int lenDst);

Parameters

pSrcSignal	Pointer to the source signal.
lenSrc	Length of the input vector.
upFactor	Upsampling factor.
downFactor	Downsampling factor.
pInterpFracMem	Pointer to the memory for interpolating fraction.
pMem	Pointer to the memory for resampling, [144] for downsampling, or [44] for upsampling.
pDstSignal	Pointer to the destination resampled signal.
lenDst	Length of the destination vector.

Description

The function ippsResamplePolyphase_AMRWBE is declared in ippsc.h file. This function performs resampling of the input signal in accordance with the values of the resampling factors upFactor (upsampling factor) and downFactor (downsampling factor). If upFactor < downFactor, the function downsamples the input 44.1/48 kHz signal, if upFactor > downFactor, the function upsamples the input signal to the 44.1/48 kHz signal. The possible combinations of the input/output frequencies and corresponding values of resampling factors are listed in the tables below.

See also 3GPP TS 26.290: “Extended AMR Wideband Speech Codec; Transcoding functions", clauses 5.1, 6.6 [AMRWB+].

Upsampling Mode
Input frequency, kHz	Upsampling factor	Downsampling factor	Output frequency, kHz
8	12	2	48
16	12	4	48
24	12	6	48
32	12	8	48
11.025	12	3	44.1
22.05	12	6	44.1

Downsampling Mode
Input frequency, kHz	Upsampling factor	Downsampling factor	Output frequency, kHz
48	2	12	8
48	4	12	16
48	6	12	24
48	8	12	32
44.1	3	12	11.025
44.1	6	12	22.05

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when one of the specified pointer is NULL.
ippStsSizeErr	Indicates an error when lenDst has an illegal value.