Obtains prediction filter coefficients using covariance method.
Syntax
IppStatus ippsPredictCoef_SBR_C_32fc_D2L(const Ipp32fc* pSrc[], Ipp32fc* pAlpha0, Ipp32fc* pAlpha1, int k0, int len);
IppStatus ippsPredictCoef_SBR_C_32f_D2L(const Ipp32f* pSrcRe[], const Ipp32f* pSrcIm[], Ipp32f* pAlpha0Re, Ipp32f* pAlpha0Im, Ipp32f* pAlpha1Re, Ipp32f* pAlpha1Im, int k0, int len);
IppStatus ippsPredictCoef_SBR_R_32f_D2L(const Ipp32f* pSrc[], Ipp32f* pAlpha0, Ipp32f* pAlpha1, int k0, int len);
Parameters
pSrc |
Array of pointers to the source real or complex matrix ([40][32]) holding the low frequency QMF-processed subband signals. |
pSrcRe |
Array of pointers ([40][32]) that contains real parts of the low frequency SBR-processed subband signals. |
pSrcIm |
Array of pointers ([40][32]) that contains imaginary parts of the low frequency SBR-processed subband signals. |
pAlpha0, pAlpha1 |
Pointers to the prediction filter coefficients used by high frequency filter. |
pAlpha0Re, pAlpha1Re |
Pointers to the arrays that contain real parts of the corresponding complex filter coefficients. |
pAlpha0Im, pAlpha1Im |
Pointers to the arrays that contain imaginary parts of the corresponding complex filter coefficients. |
k0 |
First QMF subband in the f_master table. |
len |
Autocorrelation size. |
Description
These functions are declared in the ippac.h file. The function ippsPredictCoef_SBR obtains prediction filter coefficients using covariance method.
The function ippsPredictCoef_SBR_C_32fc uses the complex input data type and complex output data type, processes the input complex matrix pSrc and stores the result in complex arrays pAlpha0 and pAlpha1.
The function ippsPredictCoef_SBR_C_32f uses the real input and output data type, storing the complex input data separately in matrices pSrcRe and pSrcIm and stores complex output data separately in pAlpha0Re, pAlpha0Im, pAlpha1Re, pAlpha1Im.
The functions ippsPredictCoef_SBR_C_32fc and ippsPredictCoef_SBR_C_32f are used in high quality SBR mode.
The function ippsPredictCoef_SBR_R_32f uses the real input and output data type. This function is used in low power SBR mode.
The prediction filter coefficients are obtained with the covariance method using the following formula:
The coefficients pAlpha0( k) and pAlpha1 (k) are calculated as follows:
The functions ippsPredictCoef_SBR_C_32f_D2L and ippsPredictCoef_SBR_R_32f_D2L are used in the float-point version of AAC decoder included into Intel IPP Samples. See introduction to this section.
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when at least one of the specified pointers is NULL. |