Manual Pages for UNIX Operating System command usage for man mlib_SignalLPCPitchAnalyze_S16

mediaLib Library Functions  mlib_SignalLPCPitchAnalyze_S16(3MLIB)



NAME
     mlib_SignalLPCPitchAnalyze_S16  -  perform  open-loop  pitch
     analysis

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

     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  deter-
     mined as following.

            Topt = T0



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mediaLib Library Functions  mlib_SignalLPCPitchAnalyze_S16(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 MLIB_SUCCESS if  successful.  Otherwise
     it returns MLIB_FAILURE.

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















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mediaLib Library Functions  mlib_SignalLPCPitchAnalyze_S16(3MLIB)



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     mlib_SignalLPCPitchAnalyze_F32(3MLIB), attributes(5)












































SunOS 5.11           Last change: 2 Mar 2007                    3