synths.c

this the source code of audio compression standard LPC. It is coded by C.

/******************************************************************
*
*	SYNTHS Version 48
*
******************************************************************
*
*  NOTE: There is excessive buffering here, BSYNZ and DEEMP should be
*        changed to operate on variable positions within SOUT.  Also,
*        the output length parameter is bogus, and PITSYN should be
*        rewritten to allow a constant frame length output
*/

#include "config.ch"
#include "lpcdefs.h"
#include "contrl.ch"

extern int ipiti[11], ivuv[11];
extern float rci[MAXORD][11], rmsi[11], pc[MAXORD];
extern float exc[MAXPIT+MAXORD], exc2[MAXPIT+MAXORD], noise[MAXPIT+MAXORD];

synths(voice, pitch, rms, rc, speech, k )
int voice[], *pitch;
float  rc[], *rms;  
float speech[];
int *k;
{
int i, j, nout;
float ratio, g2pass;
static float sout[MAXFRM];
float gprime=0.7;


*pitch = mmax(mmin(*pitch,156),20);
for (i = 1; i<=ORDER;i++)
  rc[i] = mmax(mmin(rc[i],.99),-.99);

*k = 0;
pitsyn(voice, pitch, rms, rc, ivuv-1, ipiti-1, rmsi-1, rci, &nout, &ratio );

if(nout>0) {
	for(j=0;j<nout;j++)	{
      irc2pc( rci, pc, gprime, &g2pass, j);
	
      bsynz(pc, ipiti[j], ivuv[j], sout, rmsi[j], ratio, g2pass);
		
	  deemp0( sout-1, ipiti[j] );
	  for(i=1;i<=ipiti[j];i++)	{
			(*k)++;
			speech[*k] = sout[i-1]* 0.000244140625;
	  }
	}
}



}