mediaLib Library Functions  mlibSignalLPCPitchAnalyzeS16(3MLIB)



NAME
     mlibSignalLPCPitchAnalyzeS16  -  perform  open-loop  pitch
     analysis

SYNOPSIS
     cc [ flag... ] file... -lmlib [ library... ]
     #include 

     mlibstatus mlibSignalLPCPitchAnalyzeS16(mlibs32 *pitch,
          const mlibs16 *sigwgt, const mlibs32 *region,
          mlibs32 length);


DESCRIPTION
     The   mlibSignalLPCPitchAnalyzeS16()   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  deter-
     mined as following.

            Topt = T0



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mediaLib Library Functions  mlibSignalLPCPitchAnalyzeS16(3MLIB)



            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  avail-
               able 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 MLIBSUCES if  successful.  Otherwise
     it returns MLIBFAILURE.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:















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mediaLib Library Functions  mlibSignalLPCPitchAnalyzeS16(3MLIB)



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Committed                   
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     mlibSignalLPCPitchAnalyzeF32(3MLIB), attributes(5)












































SunOS 5.11           Last change: 2 Mar 2007                    3