Implements stage 1 of MP3 hybrid analysis filterbank.
Syntax
IppStatus ippsAnalysisPQMF_MP3_16s32s(const Ipp16s* pSrcPcm, Ipp32s* pDstS, int pcmMode);
Parameters
pSrcPcm |
Pointer to the start of the buffer containing the input PCM audio vector. The samples conform to the following guidelines: must be in 16-bit, signed, little-endian, Q15 format most recent 480 (512-32) samples must be contained in the vector pSrcPcm[pcmMode*i], where i = 0,1,..,479; samples associated with the current granule should be contained in the vector pSrcPcm[ pcmMode*j], where j = 480,481,..,1055. |
pcmMode |
PCM mode flag. Communicates to PQMF filterbank the type of input PCM vector organization to expect:pcmMode = 1 denotes non-interleaved PCM input samples; pcmMode = 2 denotes interleaved PCM input samples. |
pDstS |
Pointer to the start of the 576-element block PQMF analysis output vector containing 18 consecutive blocks of 32 subband samples under the following index: pDstXs[32* i + sb], where i = 0,1,...,17 is time series index sb = 0,1,...,31 is the subband index. |
Description
The function is declared in the ippac.h file. This function implements the first stage of MP3 hybrid analysis filterbank. The function applies the critically sampled block PQMF analysis bank characterized by the 512-sample prototype window to a PCM input audio vector.
Call the function ippsAnalysisPQMF_MP3 18 times per granule on each channel, that is, 36 times per channel on each frame.
Note
All coefficients are represented using the Q7.24 format
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when any of the specified pointers is NULL. |
ippStsErr |
Indicates an error when pcmMode exceeds [1,2]. |