lflg_upd.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

/*
*****************************************************************************
*
*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
*                                R99   Version 3.3.0                
*                                REL-4 Version 4.1.0                
*
*****************************************************************************
*
*      File             : lflg_upd.c
*      Purpose          : LTP_flag update for AMR VAD option 2
*
*****************************************************************************
*/

const char lflg_upd_id[] = "@(#)$Id $";


#include "typedef.h"
#include "cnst.h"
#include "basic_op.h"
#include "oper_32b.h"
#include "count.h"

#include "vad2.h"
#include "mode.h"

/***************************************************************************
 *
 *   FUNCTION NAME: LTP_flag_update
 *
 *   PURPOSE:
 *     Set LTP_flag if the LTP gain > LTP_THRESHOLD, where the value of
 *     LTP_THRESHOLD depends on the LTP analysis window length.
 *
 *   INPUTS:
 *
 *     mode
 *                     AMR mode
 *     vadState->L_R0
 *                     LTP energy
 *     vadState->L_Rmax
 *                     LTP maximum autocorrelation
 *   OUTPUTS:
 *
 *     vadState->LTP_flag
 *                     Set if LTP gain > LTP_THRESHOLD
 *
 *   RETURN VALUE:
 *
 *     none
 *
 *************************************************************************/

void LTP_flag_update (vadState2 * st, Word16 mode)
{
	Word16 thresh;
	Word16 hi1;
	Word16 lo1;
	Word32 Ltmp;

									test(); test();
	if ((sub(mode, MR475) == 0) || (sub(mode, MR515) == 0))
	{
		thresh = (Word16)(32768.0*0.55);			move16();
	}
	else if (sub(mode, MR102) == 0)
	{
		thresh = (Word16)(32768.0*0.60);			move16();
	}
	else
	{
		thresh = (Word16)(32768.0*0.65);			move16();
	}

	L_Extract (st->L_R0, &hi1, &lo1);
	Ltmp = Mpy_32_16(hi1, lo1, thresh);				test();
	if (L_sub(st->L_Rmax, Ltmp) > 0)
	{
		st->LTP_flag = TRUE;					move16();
	}
	else
	{
		st->LTP_flag = FALSE;					move16();
	}

	return;
}