Create and initialize modified discrete cosine transform specification structure.
Syntax
IppStatus ippsMDCTFwdInitAlloc_32f(IppsMDCTFwdSpec_32f** ppMDCTSpec, int len);
IppStatus ippsMDCTFwdInitAlloc_16s(IppsMDCTFwdSpec_32s** ppMDCTSpec, int len);
IppStatus ippsMDCTInvInitAlloc_32f(IppsMDCTInvSpec_32f** ppMDCTSpec, int len);
Parameters
ppMDCTSpec |
Pointer to pointer to MDCT specification structure to be created. |
len |
Number of samples in MDCT. Since this set of functions was designed specially for audio coding, only the following values of length are supported: 12, 36, and 2k, where k ≥ 5. These values are the only values that appear in audio coding. |
Description
These functions are declared in the ippac.h header file. The functions ippsMDCTFwdInitAlloc and ippsMDCTInvInitAlloc create and initialize MDCT specification structure pMDCTSpec with the specified transform length len.
The function ippsMDCTFwdInitAlloc initializes the forward MDCT specification structure. The function ippsMDCTInvInitAlloc initializes the inverse MDCT specification structure.
ippsMDCTFwdInitAlloc_32f is used in the float-point versions of AAC decoder, AAC and MP3 encoders, ippsMDCTFwdInitAlloc_16s is used in the fixed-point version of AAC encoder, ippsMDCTInvInitAlloc_32f is used in the float-point versions of AC3, AAC, and MP3 decoders included into Intel IPP Samples. See introduction to this section.
Return Values
ippStsNoErr |
Indicates no error. |
ippStsNullPtrErr |
Indicates an error when the ppMDCTSpec pointer is NULL. |
ippStsSizeErr |
Indicates an error when len does not belong to the above set of admissible values. |
ippStsMemAllocErr |
Indicates an error when no memory is allocated. |
Note
ippsMDCTFwd_16s_Sfs does not support the length values of 12 and 36.