www.pudn.com > CryptoPhone-src-031122.zip > interp.c

/* Copyright 2001,2002,2003 NAH6 
 * All Rights Reserved 
 * 
 * Parts Copyright DoD, Parts Copyright Starium 
 * 
 */ 
 
#include "main.h" 
#include "interp.h" 
#include  
 
static void InterpolateSubFrame( 
float	cur_lsf[ORDER], 
float	prev_lsf[ORDER], 
float	lsfint[NUM_SF][ORDER], 
int	sf); 
 
static void AnalCheckForMonotonicity( 
float	cur_lsfint[NUM_SF][ORDER], 
float	prev_lsfint[ORDER], 
int	sf, 
int	frame_num); 
 
static void SynthCheckForMonotonicity( 
float	cur_lsf[ORDER], 
float	prev_lsf[ORDER]); 
 
/************************************************************************** 
*                                                                         * 
* ROUTINE 
*		Interpolate 
* 
* FUNCTION 
*		Interpolation of LSFs 
* SYNOPSIS 
*		Interpolate(lsf, lsfint, where, frame_num) 
* 
*   formal 
* 
*                       data    I/O 
*       name            type    type    function 
*       ------------------------------------------------------------------- 
*	lsf		float	 i	Frame of LSFs 
*	lsfint		float	 o	Frame of interpolated LSFs 
*	where		int	 i	analysis/synthesis flag 
*	frame_num	int	 i	Current frame number 
* 
************************************************************************** 
* 
* CALLED BY 
* 
*	Analysis Synthesis 
* 
**************************************************************************/ 
void Interpolate( 
float 	lsf[ORDER], 
float	lsfint[NUM_SF][ORDER], 
int 	where, 
int	frame_num) 
{ 
int		i; 
static float	prev_ana_sf_lsf[ORDER]; 
static float	prev_ana_ff_lsf[ORDER]= { 	0.03, 0.05, 0.09, 0.13, 0.19,  
						0.23, 0.29, 0.33, 0.39, 0.44 
				   	}; 
static float	prev_syn_lsf[ORDER]= 	{ 	0.03, 0.05, 0.09, 0.13, 0.19,  
						0.23, 0.29, 0.33, 0.39, 0.44 
				   	}; 
 
/*  Perform interpolation depending on whether this is analysis or synthesis */ 
switch(where)	{ 
/*  Analysis interpolation */ 
/*-----------------------------------------------------------------------*/ 
	case ANALYSIS:  
	  for(i=0;i