mlib_SignalLPCPitchAnalyzemediaLibILibrarmlib_SignalLPCPitchAnalyze_S16(3MLIB)NAMEmlib_SignalLPCPitchAnalyze_S16 - perform open-loop pitch analysis
SYNOPSIS
cc [ flag... ] file... -lmlib [ library... ]
#include <mlib.h>
mlib_status mlib_SignalLPCPitchAnalyze_S16(mlib_s32 *pitch,
const mlib_s16 *sigwgt, const mlib_s32 *region,
mlib_s32 length);
DESCRIPTION
The mlib_SignalLPCPitchAnalyze_S16() function performs open-loop pitch
analysis.
The open-loop pitch analysis uses perceptual weighted signal and is
done with following steps.
In the first step, three maxima of the correlation
N-1
R(k) = SUM sw(j) * sw(j-k)
j=0
where N = length, is located for each of the three search regions.
In the second step, the retained maxima R(Ti), i=0,1,2 are normalized
as following.
R(Ti)Rn(ti) = ---------------------, i=0,1,2
N-1 2
SQRT(SUM sw(j-Ti) )
j=0
where N = length.
In the third step, the best open-loop delay Topt is determined as fol‐
lowing.
Topt = T0
if (Rn(t1) ≥ (0.85 * Rn(Topt))
Topt = t1
if (Rn(t2) ≥ (0.85 * Rn(Topt))
Topt = t2
See G.729, G.729A, GSM EFR standards.
PARAMETERS
The function takes the following arguments:
pitch The speech pitch estimated.
sigwgt The weighted signal vector with samples in Q15 format. sigwgt
points to the current sample of the weighted signal vector,
length samples must be availabe after this point, and
MAX{region[i],i=0,1,...,5} samples must be available before
this point.
region The lower/upper boundaries of the three search regions, where
region[2*i] is the lower boundary of search region i and
region[2*i+1] is the upper boundary of search region i.
length The length of the signal vectors over which the correlation
is calculated.
RETURN VALUES
The function returns MLIB_SUCCESS if successful. Otherwise it returns
MLIB_FAILURE.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOmlib_SignalLPCPitchAnalyze_F32(3MLIB), attributes(5)SunOS 5.10 2 Mar 2mlib_SignalLPCPitchAnalyze_S16(3MLIB)
