RTL271_1/evrcc/code/apf.c

/**********************************************************************
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even though this Publication may contain the Contribution or a derivative 
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the Source's rights to license as herein provided.

When a Contribution is submitted by the Source(s) to assist the 
formulating groups of 3GPP2 or any of its Organizational Partners, it 
is proposed to the Committee as a basis for discussion and is not to 
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specifically reserve(s) the right to amend or modify the material 
contained in the Contribution. Nothing contained in the Contribution 
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With respect to the Software necessary for the practice of any or 
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*******************************************************************/
 
/*======================================================================*/
/*     Enhanced Variable Rate Codec - Bit-Exact C Specification         */
/*     Copyright (C) 1997-1998 Telecommunications Industry Association. */
/*     All rights reserved.                                             */
/*----------------------------------------------------------------------*/
/* Note:  Reproduction and use of this software for the design and      */
/*     development of North American Wideband CDMA Digital              */
/*     Cellular Telephony Standards is authorized by the TIA.           */
/*     The TIA does not authorize the use of this software for any      */
/*     other purpose.                                                   */
/*                                                                      */
/*     The availability of this software does not provide any license   */
/*     by implication, estoppel, or otherwise under any patent rights   */
/*     of TIA member companies or others covering any use of the        */
/*     contents herein.                                                 */
/*                                                                      */
/*     Any copies of this software or derivative works must include     */
/*     this and all other proprietary notices.                          */
/*======================================================================*/
/*  Memory Usage:                           */
/*      ROM:                            */
/*      Static/Global RAM:                      */
/*      Stack/Local RAM:                    */
/*----------------------------------------------------------------------*/

/* Adaptive post filter */

//#include "mathevrc.h"
#include "dsp_math.h"
#include "mathdp31.h"
#include "mathadv.h"
#include "macro.h"
#include "d_globs.h"


void    apf(INT16 *in, INT16 *coeff, INT16 *out, INT32 delayi, INT16 alpha,
	    INT16 beta, INT16 u, INT16 agc, INT16 ltgain, INT16 order, INT16 length, INT16 br)
{

	static int FirstTime = 1;

	static INT16 FIRmem[ORDER];	/* FIR filter memory */
	static INT16 IIRmem[ORDER];	/* IIR filter memory */
	static INT16 last;
	static INT16 Residual[ACBMemSize + SubFrameSize];	/* local residual */

	INT16   wcoef1[ORDER];
	INT16   wcoef2[ORDER];
	INT16   scratch[SubFrameSize];
	INT16   temp[SubFrameSize];
	INT16   mem[ORDER];
	INT32	sum1, sum2;
	INT32    gamma, APFgain;
	INT16   i, j, n, best;
	INT16	Stemp, shift1, shift2;
	INT32	Ltemp;


	/* initialization -- should be done in init routine for implementation */
	if (FirstTime)
	{
		FirstTime = 0;
		for (i = 0; i < ORDER; i++)
			FIRmem[i] = 0;
		for (i = 0; i < ORDER; i++)
			IIRmem[i] = 0;
		for (i = 0; i < ACBMemSize; i++)
			Residual[i] = 0;
		last = 0;
	}

	/* Compute weighted LPC coefficients */
	weight(wcoef1, coeff, alpha, order);
	weight(wcoef2, coeff, beta, order);


	/* Tilt speech  */

	/*...no tilt in non-voiced regions...*/
	for (i = 0, sum2 = 0; i < length - 1; i++)
		sum2 = L_mac(sum2, in[i], in[i + 1]);
	if (sum2 < 0)
		u = 0;		/*...no tilt...*/

	for (i = 0; i < length; i++)
	{
		scratch[i] = msu_r(L_deposit_h(in[i]), u, last);
		last = in[i];
	}

	/* Compute  residual */
	fir(scratch, scratch, wcoef1, FIRmem, order, length);

	for (i = 0; i < SubFrameSize ; i++)
	  Residual[ACBMemSize+i] = scratch[i];

	/* INT32 term filtering */
	/* Find best integer delay around delayi */
	j = extract_h(L_add(delayi, 32768));
	sum1 = 0;
        shift1 = 1;
	best = j;
	for (i = Max(DMIN, j - 3); i <= Min(DMAX, j + 3); i++)
	{
                shift2 = 1;
		for (n = ACBMemSize, sum2 = 0; n < ACBMemSize + length; n++)
		{
			Ltemp = L_mult(Residual[n], Residual[n - i]);
			Ltemp = L_shr(Ltemp, shift2);
			sum2 = L_add(sum2, Ltemp);
			if (sum2 >= 0x40000000)
			{
				sum2 = L_shr(sum2, 1);
				shift2++;
			}
		}

                if( ((shift1 >= shift2) && (L_shr(sum2,sub(shift1,shift2)) > sum1))
                   || ((shift1 < shift2) && (sum2 > L_shr(sum1,sub(shift2,shift1)))))
		{
			sum1 = sum2;
			shift1 = shift2;
			best = i;
		}
	}

	/* Get beta for delayi */
	shift1 = 1;
	for (i = ACBMemSize, sum1 = 0; i < ACBMemSize + length; i++)
	{
		Ltemp = L_mult(Residual[i - best], Residual[i - best]);
		Ltemp = L_shr(Ltemp, shift1);
		sum1 = L_add(sum1, Ltemp);
		if (sum1 >= 0x40000000)
		{
			sum1 = L_shr(sum1, 1);
			shift1++;
		}
	}
	shift2 = 1;
	for (i = ACBMemSize, sum2 = 0; i < ACBMemSize + length; i++)
	{
		Ltemp = L_mult(Residual[i], Residual[i - best]);
		Ltemp = L_shr(Ltemp, shift2);
		sum2 = L_add(sum2, Ltemp);
		if (sum2 >= 0x40000000)
		{
			sum2 = L_shr(sum2, 1);
			shift2++;
		}
	}
	if (shift1 > shift2)
	{
		shift1 = sub(shift1, shift2);
		sum2 = L_shr(sum2, shift1);
	}
	else if (shift1 < shift2)
	{
		shift2 = sub(shift2, shift1);
		sum1 = L_shr(sum1, shift2);
	}

	if ((sum2 == 0) || (sum1 == 0) || (br == 1))
		for (i = 0; i < length; i++)
			temp[i] = Residual[i + ACBMemSize];
	else
	{
		if (sum2 >= sum1)
			gamma = 0x7fffffff;		/* Clip gamma at 1.0 */
		else if (sum2 < 0)
			gamma = 0;
		else
		{
			shift1 = norm_l(sum1);
			sum1 = L_shl(sum1, shift1);
			sum2 = L_shl(sum2, shift1);
			gamma = L_divide(sum2, sum1);
		}

		if (gamma < 0x40000000)
			for (i = 0; i < length; i++)
				temp[i] = Residual[i + ACBMemSize];
		else
		{
			/* Do actual filtering */
			for (i = 0; i < length; i++)
			{
				Ltemp = L_mpy_ls(gamma, ltgain);
				Ltemp = L_mpy_ls(Ltemp, Residual[ACBMemSize + i - best]);
				temp[i] = add(Residual[ACBMemSize + i], round32(Ltemp));
			}
		}

	}


	/* iir INT16 term filter - first run */
	for (i = 0; i < length; i++)
		scratch[i] = temp[i];
	for (i = 0; i < order; i++)
		mem[i] = IIRmem[i];
	iir(scratch, scratch, wcoef2, mem, order, length);


	/* Get filter gain */
	shift1 = 1;
	for (i = 0, sum1 = 0; i < length; i++)
	{
		Ltemp = L_mult(in[i], in[i]);
		Ltemp = L_shr(Ltemp, shift1);
		sum1 = L_add(sum1, Ltemp);
		if (sum1 >= 0x40000000)
		{
			sum1 = L_shr(sum1, 1);
			shift1++;
		}
	}
	shift2 = 1;
	for (i = 0, sum2 = 0; i < length; i++)
	{
		Ltemp = L_mult(scratch[i], scratch[i]);
		Ltemp = L_shr(Ltemp, shift2);
		sum2 = L_add(sum2, Ltemp);
		if (sum2 >= 0x40000000)
		{
			sum2 = L_shr(sum2, 1);
			shift2++;
		}
	}
	if (shift1 > shift2)
	{
		shift1 = sub(shift1, shift2);
		sum2 = L_shr(sum2, shift1);
	}
	else if (shift1 < shift2)
	{
		shift2 = sub(shift2, shift1);
		sum1 = L_shr(sum1, shift2);
	}

	if (sum2 != 0)
	{
		shift1 = norm_l(sum2);
		sum2 = L_shl(sum2, shift1);
		shift1 = sub(shift1, 2);	/* For (1. < APFgain < 2.) */
		sum1 = L_shl(sum1, shift1);
		Ltemp = L_divide(sum1, sum2);
		shift1 = norm_l(Ltemp);
		Ltemp = L_shl(Ltemp, shift1);
		Stemp = sqroot(Ltemp);
		if (shift1 & 1)
			APFgain = L_mult(0x5a82, Stemp);
		else
			APFgain = L_deposit_h(Stemp);
		shift1 = shr(shift1, 1);
		APFgain = L_shr(APFgain, shift1);

		/* Re-normalize the speech signal */
		for (i = 0; i < length; i++)
		{
			Ltemp = L_mpy_ls(APFgain, temp[i]);
			Ltemp = L_shl(Ltemp, 1);  /* For (1. < APFgain < 2.) */
			temp[i] = round32(Ltemp);
		}
	}
	else
		APFgain = 0x40000000;


	/* iir INT16 term filter - second run */
	iir(out, temp, wcoef2, IIRmem, order, length);

	/* Update residual buffer */
	for (i = 0; i < ACBMemSize; i++)
		Residual[i] = Residual[i + length];
}