Calculates adaptive gain control.
Syntax
IppStatus ippsGainControl_G729_16s_I (const Ipp16s* pSrc, Ipp16s* pSrcDst, Ipp16s* pGain);
IppStatus ippsGainControl_G729A_16s_I (const Ipp16s* pSrc, Ipp16s* pSrcDst, Ipp16s* pGain);
IppStatus ippsGainControl_G729_32f_I (Ipp32f gainScalingFactor, Ipp32f gainFactor, Ipp32f* pSrcDst, Ipp32f* pGain);
Parameters
pSrc |
Pointer to the source reconstructed speech vector [40]. |
gainScalingFactor |
Gain scaling factor, which is the ratio of energies of the reconstructed speech signal and post-filtered output signal. |
gainFactor |
Gain adjustment factor. |
pSrcDst |
Pointer to the input post-filtered signal and output gain-compensated signal vector [40]. |
pGain |
Pointer to the output adaptive gain. |
Description
These functions are declared in the ippsc.h file. The function ippsGainControl_G729 compensates the gain difference between the reconstructed speech signal sr, given by pSrc , and the filtered signal sf, given by pSrcDst. First, the gain factor G is calculated as follows:
The output gain spf for the post-filtered signal pSrcDst is calculated as:
spf = g(n) * sf(n) , n = 0,..., 39 ,
where
g(n) = 0.85*g(n-1) + 0.15*G , n = 0,..., 39 , g(-1) = 1.0 .
The function returns g(39) in pGain.
For the function ippsGainControl_G729A_16s, the gain factor G and factors g(n) are calculated differently as given by:
g(n) = 0.9*g(n-1) + 0.1*G
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when one of the specified pointers is NULL. |