G.723.1 Functions

The Intel IPP functions described in this section implement building blocks that can be used to create speech codecs compliant with the ITU-T Recommendation G.723.1 (see [ITU723], [ITU723A]). The list of these functions is given in the table below.

Intel IPP G.723.1 Functions
Function Base Name	Operation
Linear Prediction Analysis Functions
AutoCorr_G723	Estimates the autocorrelation of a vector.
AutoCorr_NormE_G723	Estimates normal autocorrelation of a vector.
LevinsonDurbin_G723	Calculates the LP coefficients from the autocorrelation coefficients.
LPCToLSF_G723	Converts LP coefficients to LSF coefficients.
LSFToLPC_G723	Converts LSF coefficients to the LP coefficients.
LSFDecode_G723	Performs inverse quantization of LSFs.
LSFQuant_G723	Quantizes LSF coefficients.
Codebook Search Functions
OpenLoopPitchSearch_G723	Searches for an optimal pitch value.
ACELPFixedCodebookSearch_G723	Searches the ACELP fixed codebook for the excitation.
AdaptiveCodebookSearch_G723	Searches for the close loop pitch and the adaptive gain index.
MPMLQFixedCodebookSearch_G723	Searches the MP-MLQ fixed codebook for the excitation.
ToeplizMatrix_G723	Calculates 416 elements of the Toepliz matrix for fixed codebook search.
Gain Quantization Functions
GainQuant_G723	Implements MP-MLQ gain estimation and quantization.
GainControl_G723	Extracts delayed pitch contribution.
Filter Functions
HighPassFilter_G723	Performs high-pass filtering of the input signal.
IIR16s_G723	Performs IIR filtering.
SynthesisFilter_G723	Computes the speech signal by filtering the input speech through the synthesis filter 1/A(z).
TiltCompensation_G723	Computes tilt compensation filter.
HarmonicSearch_G723	Searches for the harmonic delay and gain for the harmonic noise shaping filter.
HarmonicNoiseSubtract_G723	Performs harmonic noise shaping.
DecodeAdaptiveVector_G723	Restores the adaptive codebook vector from excitation, pitch, and adaptive gain.
PitchPostFilter_G723	Calculates coefficients of the pitch post filter.

These functions are used in the Intel IPP G.723.1 Speech Encoder-Decoder sample downloadable from http://www.intel.com/cd/software/products/asmo-na/eng/220046.htm.