Obtains a prediction filter coefficient using covariance method.
Syntax
IppStatus ippsPredictOneCoef_SBRHQ_32sc_D2L(const Ipp32sc* pSrc[], Ipp32sc* pAlpha0, Ipp32sc* pAlpha1, int k, int lenCorr);
IppStatus ippsPredictOneCoef_SBRLP_32s_D2L(const Ipp32s* pSrc[], Ipp32s* pAlpha0, Ipp32s* pAlpha1, Ipp32s* pRefCoef, int k, int lenCorr, int flag);
Parameters
pSrc |
Array of pointers to the source real or complex matrix holding the low frequency QMF-processed subband signals. |
pAlpha0, pAlpha1 |
Pointers to the prediction filter coefficients used by high frequency filter. |
pRefCoef |
Pointer to the reflection coefficient that is used by the aliasing detection algorithm (LP mode only). |
k |
Number of the input matrix column. This parameter is used for calculating prediction coefficients. |
lenCorr |
Aautocorrelation size, this parameter is used for calculating prediction coefficients. |
flag |
Flag that specifies the result of calculation (LP mode only). If it is NULL (0), then only the reflection coefficient is calculated. Otherwise both prediction and reflection coefficients are calculated. |
Description
These functions are declared in the ippac.h file and obtain a prediction filter coefficient using covariance method. The ippsPredictOneCoef_SBRHQ_32sc_D2L function is used in high quality SBR mode and the ippsPredictOneCoef_SBRLP_32s_D2L function is used in low power SBR mode.
Prediction and reflection coefficients have the same position of decimation point (Q format), independent of Q format of pSrc. It is Q(29). Q format of pSrc can be arbitrary but the recommended value is Q(5).
The prediction filter coefficient is obtained with the covariance method using the following formula:
The functions ippsPredictOneCoef_SBRHQ_32sc_D2L and ippsPredictOneCoef_SBRLP_32s_D2L are used in the fixed-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. |