intanaly.h

g729 coding ipaddressing

/**************************************************************************
*
* ROUTINE
*				intanaly
*
* FUNCTION
*				Linearly interpolate between transmitted LSPs
*				to generate nn (=4) intermediate sets of LSP
*				frequencies for subframe analysis. 
*				
*
* SYNOPSIS
*				subroutine intanaly(lspnew, nn, lsp)
*
*	formal 
*
*						data	I/O
*		name			type	type	function
*		-------------------------------------------------------------------
*		lspnew			float	i		new frequency array
*		nn				int 	i		number of segments/frame
*		lsp 			float	o		interpolated frequency matrix
*
*	external 
*						data	I/O
*		name			type	type	function
*		-------------------------------------------------------------------
*		no				int 	i
*		frame			int 	i
*
***************************************************************************
*
* DESCRIPTION
*               This routine linearly interpolates lsp's for analysis in
*		nn (=4) subframes.	This is a combination of inter- and 
*		intra-frame interpolation.	There are two routines, one for the 
*		analyzer and one for the synthesizer.
*
*				The lsps are interpolated from two transmitted frames,
*		 old and new.  The lsp interpolation is calculated as follows:
*
*		superframe: 	  old				   new
*
*				|					  | 					|
*				|---------------------|---------------------|
*				|					  | 					|
*
*                \                                         /
*                 \                                       /
*
*		subframe:		  1 	  2 	   3		4
*					 |									 |
*			   ...---|--------|--------|--------|--------|
*					 |									 |
*						  v 	  v 	   v		v
*
*		weighting:
*				old:	 7/8	  5/8	   3/8		1/8
*				new:	 1/8	  3/8	   5/8		7/8
*
*		Note: This is dependent on nn = ll/l = 4!
*		
***************************************************************************
*
* CALLED BY
*
*		celp
*
* CALLS
*
*
*
**************************************************************************/

#ifdef CELP_USE_CONTEXT
#define	tempfreq	(ctx->INTANALY_tempfreq)
#else
static float tempfreq;
#endif
static const float w[2][4] =   { {0.875, 0.625, 0.375, 0.125},
								{0.125, 0.375, 0.625, 0.875}};

static void intanaly(float lspnew[], int nn, float a_lsp[][MAXNO])
{
  int i, j, nonmono;
#ifdef CELP_USE_CONTEXT
#define	lspold	(ctx->INTANALY_lspold)
#define	oldlsp	(ctx->INTANALY_oldlsp)
#else
  static float lspold[MAXNO] = {.03f, .05f, .09f, .13f, .19f, .23f, .29f, .33f, .39f, .44f};
  static float oldlsp[MAXNO];
#endif

  for (i = 0; i < nn; i++)

  /* *interpolate lsp's                                          */

  {
	for (j = 0; j < no; j++)
	  a_lsp[i][j] = w[0][i]*lspold[j] + w[1][i]*lspnew[j];

	/* *OPTIONAL bug checker
       *check for monotonically increasing lsp's
	   *swap crossed LSPs										*/
  
	for (j = 1; j < no; j++)
	{
	  if (a_lsp[i][j] < a_lsp[i][j - 1])
	  {
#ifdef CELPDIAG
        fprintf(stderr, "intanaly: Swapping nonmono lsps @ frame %d\n", frame);
#endif
		tempfreq = a_lsp[i][j];
		a_lsp[i][j] = a_lsp[i][j - 1];
		a_lsp[i][j - 1] = tempfreq;
	  }
	}

    /* *recheck for monotonically increasing lsp's
	   *substitute old LSPs (they must be really messed up!)	*/
  
	nonmono = FALSE;
	for (j = 1; j < no; j++)
	{
	  if (a_lsp[i][j] < a_lsp[i][j - 1]) 
		nonmono = TRUE;
	}
	if (nonmono)
	{
#ifdef CELPDIAG
        fprintf(stderr, "intanaly: Resetting interp LSP at frame %d\n", frame);
#endif
	  for (j = 0; j < no; j++)
	  {
		if (i == 0)
		  a_lsp[i][j] = oldlsp[j];
		else
		  a_lsp[i][j] = a_lsp[i - 1][j];
	  }
	}
  }
  
  /*            *save lsp's for next pass                               */
  
  for (j = 0; j < no; j++)
  {
	lspold[j] = lspnew[j];
	oldlsp[j] = a_lsp[nn][j];
  }
}
#ifdef CELP_USE_CONTEXT
#undef	tempfreq
#undef	lspold
#undef	oldlsp
#endif