QMFDecode

Performs QMF synthesis filtering.

Syntax

IppStatus ippsQMFDecode_G7291_16s (const Ipp16s* pSrcLowBand, const Ipp16s* pSrcHighBand, Ipp16s valGainSwitching, int len, Ipp16s* pDst, IppsQMFState_G7291_16s* pState);

Parameters

pSrcLowBand	Pointer to the input lower-band vector [len].
pSrcHighBand	Pointer to the input higher-band vector [len].
valGainSwitching	Gain attenuation factor.
len	Number of samples.
pDst	Pointer to the output vector [len*2].
pState	Pointer to the memory supplied for QMF decode.

Description

The function ippsQMFDecode_G7291 is declared in the ippsc.h file. This function is used to obtain the output signal sampled at 16000 Hz from two input signals sampled at 8000 Hz: a lower band signal and a higher band signal. Note that the QMF synthesis filterbank performs an additional signal upscaling (by 2) to compensate the signal downscaling (by 2) done through the encoding. The description of the QMF synthesis algorithm can be found in [ITU7291] section 7.5.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when one of the specified pointers is NULL.
ippStsSizeErr	Indicates an error when len is less than or equal to 0, or greater than 320.