msamr/opencore-amr/opencore/codecs_v2/audio/gsm_amr/amr_nb/enc/src/cor_h_x.cpp
/* ------------------------------------------------------------------
* Copyright (C) 1998-2009 PacketVideo
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied.
* See the License for the specific language governing permissions
* and limitations under the License.
* -------------------------------------------------------------------
*/
/****************************************************************************************
Portions of this file are derived from the following 3GPP standard:
3GPP TS 26.073
ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
Available from http://www.3gpp.org
(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
Permission to distribute, modify and use this file under the standard license
terms listed above has been obtained from the copyright holder.
****************************************************************************************/
/*
------------------------------------------------------------------------------
Filename: cor_h_x.cpp
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "typedef.h"
#include "cnst.h"
#include "cor_h_x.h"
#include "basic_op.h"
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL STORE/BUFFER/POINTER DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; EXTERNAL FUNCTION REFERENCES
; Declare functions defined elsewhere and referenced in this module
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
; Declare variables used in this module but defined elsewhere
----------------------------------------------------------------------------*/
/*
------------------------------------------------------------------------------
FUNCTION NAME: cor_h_x
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
h = vector containing the impulse response of the weighted synthesis
filter; vector contents are of type Word16; vector length is
2 * L_SUBFR
x = target signal vector; vector contents are of type Word16; vector
length is L_SUBFR
dn = vector containing the correlation between the target and the
impulse response; vector contents are of type Word16; vector
length is L_CODE
sf = scaling factor of type Word16 ; 2 when mode is MR122, 1 for all
other modes
Outputs:
dn contents are the newly calculated correlation values
pOverflow = pointer of type Flag * to overflow indicator.
Returns:
None
Global Variables Used:
None
Local Variables Needed:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
This function computes the correlation between the target signal (x) and the
impulse response (h).
The correlation is given by: d[n] = sum_{i=n}^{L-1} x[i] h[i-n],
where: n=0,...,L-1
d[n] is normalized such that the sum of 5 maxima of d[n] corresponding to
each position track does not saturate.
------------------------------------------------------------------------------
REQUIREMENTS
None
------------------------------------------------------------------------------
REFERENCES
cor_h.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
void cor_h_x (
Word16 h[], // (i): impulse response of weighted synthesis filter
Word16 x[], // (i): target
Word16 dn[], // (o): correlation between target and h[]
Word16 sf // (i): scaling factor: 2 for 12.2, 1 for others
)
{
cor_h_x2(h, x, dn, sf, NB_TRACK, STEP);
}
void cor_h_x2 (
Word16 h[], // (i): impulse response of weighted synthesis filter
Word16 x[], // (i): target
Word16 dn[], // (o): correlation between target and h[]
Word16 sf, // (i): scaling factor: 2 for 12.2, 1 for others
Word16 nb_track,// (i): the number of ACB tracks
Word16 step // (i): step size from one pulse position to the next
in one track
)
{
Word16 i, j, k;
Word32 s, y32[L_CODE], max, tot;
// first keep the result on 32 bits and find absolute maximum
tot = 5;
for (k = 0; k < nb_track; k++)
{
max = 0;
for (i = k; i < L_CODE; i += step)
{
s = 0;
for (j = i; j < L_CODE; j++)
s = L_mac (s, x[j], h[j - i]);
y32[i] = s;
s = L_abs (s);
if (L_sub (s, max) > (Word32) 0L)
max = s;
}
tot = L_add (tot, L_shr (max, 1));
}
j = sub (norm_l (tot), sf);
for (i = 0; i < L_CODE; i++)
{
dn[i] = pv_round (L_shl (y32[i], j));
}
}
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
void cor_h_x(
Word16 h[], /* (i): impulse response of weighted synthesis filter */
Word16 x[], /* (i): target */
Word16 dn[], /* (o): correlation between target and h[] */
Word16 sf, /* (i): scaling factor: 2 for 12.2, 1 for others */
Flag *pOverflow /* (o): pointer to overflow flag */
)
{
register Word16 i;
register Word16 j;
register Word16 k;
Word32 s;
Word32 y32[L_CODE];
Word32 max;
Word32 tot;
Word16 *p_x;
Word16 *p_ptr;
Word32 *p_y32;
tot = 5;
for (k = 0; k < NB_TRACK; k++) /* NB_TRACK = 5 */
{
max = 0;
for (i = k; i < L_CODE; i += STEP) /* L_CODE = 40; STEP = 5 */
{
s = 0;
p_x = &x[i];
p_ptr = h;
for (j = (L_CODE - i - 1) >> 1; j != 0; j--)
{
s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
}
s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
if (!((L_CODE - i) & 1)) /* if even number of iterations */
{
s += ((Word32) * (p_x++) * *(p_ptr++)) << 1;
}
y32[i] = s;
if (s < 0)
{
s = -s;
}
if (s > max)
{
max = s;
}
}
tot += (max >> 1);
}
j = norm_l(tot) - sf;
p_ptr = dn;
p_y32 = y32;;
for (i = L_CODE >> 1; i != 0; i--)
{
s = L_shl(*(p_y32++), j, pOverflow);
*(p_ptr++) = (s + 0x00008000) >> 16;
s = L_shl(*(p_y32++), j, pOverflow);
*(p_ptr++) = (s + 0x00008000) >> 16;
}
return;
}