NoiselessDecode

Performs noiseless decoding.

Syntax

IppStatus ippsNoiselessDecode_AAC(Ipp8u** ppBitStream, int* pOffset, IppAACMainHeader* pAACMainHeader, Ipp16s* pDstScaleFactor, Ipp32s* pDstQuantizedSpectralCoef, Ipp8u* pDstSfbCb, Ipp8s* pDstTnsFiltCoef, IppAACChanInfo* pChanInfo, int winSequence, int maxSfb, int commonWin, int scaleFlag, int audioObjectType);

Parameters

ppBitStream	Double pointer to the bitstream to be parsed. It is updated after decoding.
pOffset	Pointer to the offset in one byte. It is updated after decoding.
pAACMainHeader	Pointer to main header information. Not used for scalable objects.
	When commonWin== 0 && scaleFlag ==0, you need to decode LTP information and save it in pAACMainHeader-> pLtpInfo[].
pChanInfo	Pointer to channel information structure.
windowSequence	Window type, short or long.
maxSfb	Number of scale factor bands.
commonWin	Indicates if the channel pair uses the same ICS information.
scaleFlag	Flag indicating whether the scalable type is used.
audioObjectType	Audio object type indicator: 1 indicates the main type, 2 indicates the LC type, 6 indicates the scalable mode.
pDstScaleFactor	Pointer to the parsed scalefactor.
pDstQuantizedSpectralCoef	Pointer to the quantized spectral coefficients after Huffman decoding.
pDstSfbCb	Pointer to the scale factor codebook index.
pDstTnsFiltCoef	Pointer to TNS filter coefficients. Not used for scalable objects.

Description

This function is declared in the ippac.h file. This is a general noiseless decoding module for MPEG-2 and MPEG-4 objects.

In case one scale factor band uses PNS in MPEG-4 AAC scalable object, pDstScaleFactor contains the noise energy for this scale factor band and pDstSfbCb[sfb] must be NOISE_HCB(13). The spectrum in this scale factor band is not necessarily Huffman-decoded, and the pDstQuantizedSpectralCoef of this scale factor band can be zero.

In AAC scalable object, pDstTnsFiltCoef and pAACMainHeader are not used.

Return Values

ippStsNoErr	Indicates no error.
ippStsNullPtrErr	Indicates an error when at least one of the pointers is NULL.
ippStsAacBitOffsetErr	Indicates an error when pOffset is out of the range [0,7].
ippStsAacComWinErr	Indicates an error when commonWin exceeds [0,1].
ippStsAacMaxSfbErr	Indicates an error when maxSfb exceeds [0,IPP_AAC_MAX_SFB].
ippStsAacSmplRateIdxErr	Indicates an error when pChanInfo-> samplingRateIndex exceeds [0,11].
ippStsAacCoefValErr	Indicates an error when the quantized coefficients value pointed to by pDstCoef exceeds the range of [-8191,8191].