1mlib_SignalLPCPitchAnalyze_mSe1d6i(a3LMiLbIBL)ibrarymlFiubn_cStiigonnaslLPCPitchAnalyze_S16(3MLIB)
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NAME

6       mlib_SignalLPCPitchAnalyze_S16 - perform open-loop pitch analysis
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SYNOPSIS

9       cc [ flag... ] file... -lmlib [ library... ]
10       #include <mlib.h>
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12       mlib_status mlib_SignalLPCPitchAnalyze_S16(mlib_s32 *pitch,
13            const mlib_s16 *sigwgt, const mlib_s32 *region,
14            mlib_s32 length);
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DESCRIPTION

18       The  mlib_SignalLPCPitchAnalyze_S16() function performs open-loop pitch
19       analysis.
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22       The open-loop pitch analysis uses perceptual  weighted  signal  and  is
23       done with following steps.
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26       In the first step, three maxima of the correlation
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28                     N-1
29              R(k) = SUM sw(j) * sw(j-k)
30                     j=0
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34       where N = length, is located for each of the three search regions.
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37       In  the  second step, the retained maxima R(Ti), i=0,1,2 are normalized
38       as following.
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40                                R(Ti)
41              Rn(ti) = ---------------------, i=0,1,2
42                             N-1         2
43                        SQRT(SUM sw(j-Ti) )
44                             j=0
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48       where N = length.
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51       In the third step, the best open-loop delay Topt is determined as  fol‐
52       lowing.
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54              Topt = T0
55              if (Rn(t1) ≥ (0.85 * Rn(Topt))
56                   Topt = t1
57              if (Rn(t2) ≥ (0.85 * Rn(Topt))
58                   Topt = t2
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62       See G.729, G.729A, GSM EFR standards.
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PARAMETERS

65       The function takes the following arguments:
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67       pitch     The speech pitch estimated.
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70       sigwgt    The weighted signal vector with samples in Q15 format. sigwgt
71                 points to the current sample of the weighted  signal  vector,
72                 length  samples  must  be  availabe  after  this  point,  and
73                 MAX{region[i],i=0,1,...,5} samples must be  available  before
74                 this point.
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77       region    The lower/upper boundaries of the three search regions, where
78                 region[2*i] is the lower boundary  of  search  region  i  and
79                 region[2*i+1] is the upper boundary of search region i.
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82       length    The  length  of the signal vectors over which the correlation
83                 is calculated.
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RETURN VALUES

87       The function returns MLIB_SUCCESS if successful. Otherwise  it  returns
88       MLIB_FAILURE.
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ATTRIBUTES

91       See attributes(5) for descriptions of the following attributes:
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96       ┌─────────────────────────────┬─────────────────────────────┐
97       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
98       ├─────────────────────────────┼─────────────────────────────┤
99       │Interface Stability          │Committed                    │
100       ├─────────────────────────────┼─────────────────────────────┤
101       │MT-Level                     │MT-Safe                      │
102       └─────────────────────────────┴─────────────────────────────┘
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SEE ALSO

105       mlib_SignalLPCPitchAnalyze_F32(3MLIB), attributes(5)
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109SunOS 5.11                        2 Mar 20m0l7ib_SignalLPCPitchAnalyze_S16(3MLIB)