RT Audio Functions

The Intel IPP functions described in this section if properly combined can be used to construct the speech codec compliant to the Microsoft Real-Time (RT) Audio codec. The primitives are primarily designed to implement the well-defined, computationally expensive core operations that comprise the codec portion of the RT Audio system. The RT Audio codec comprises a fixed and variable rate algorithms intended for encoding 16-bit uniform PCM at the sampling rate of 8 and 16 KHz at bit rates 8800 and 18000 bps respectively.

The list of these functions is given in the table below.

Intel MSRT Audio Functions
Function Base Name	Operation
LPCToLSP_RTA	Converts LP coefficients to LSP coefficients
LSPToLPC_RTA	Converts LSP coefficients to LP coefficients
LevinsonDurbin_RTA	Calculates LP coefficients from the autocorrelation coefficients
QMFGetStateSize_RTA	Calculates the size of the QMF filter state memory
QMFInit_RTA	Initializes the QMF filter state memory
QMFDecode_RTA	Performs QMF synthesis
QMFEncode_RTA	Performs QMF analysis
PostFilterGetStateSize_RTA	Calculates the size of the post filter state memory
PostFilterInit_RTA	Initializes the post filter state memory
PostFilter_RTA	Restores speech signal from the residual
AdaptiveCodebookSearch_RTA	Searches for the adaptive codebook index and the lag, and computes the adaptive vector
FixedCodebookSearch_RTA, FixedCodebookSearchBuffer_RTA, FixedCodebookSearchRandom_RTA	Searches for the fixed codebook vector
FixedCodebookSearch_RTA_GetBufferSize	Calculates the size of the working buffer for the search function
LSPQuant_RTA	Performs quantization of LSP coefficients
HighPassFilter_RTA	Performs high-pass filtering
BandPassFilter_RTA	Performs band pass filtering