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/* ------------------------------------------------------------------
* 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.
****************************************************************************************/
/*
------------------------------------------------------------------------------
Pathname: ./audio/gsm-amr/c/src/d2_11pf.c
Functions:
Date: 01/28/2002
------------------------------------------------------------------------------
REVISION HISTORY
Description: Modified to place file in the correct template format. Eliminated
use of special functions to perform simple mathematical operations.
Description: Per review comments...
(1) Removed include of "count.h" and "basic_op.h"
Description: Replaced "int" and/or "char" with OSCL defined types.
Description:
------------------------------------------------------------------------------
MODULE DESCRIPTION
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "d2_11pf.h"
#include "typedef.h"
#include "cnst.h"
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
#define NB_PULSE 2
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL VARIABLE DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
/*
------------------------------------------------------------------------------
FUNCTION NAME: decode_2i40_11bits
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
sign -- Word16 -- signs of 2 pulses.
index -- Word16 -- Positions of the 2 pulses.
Outputs:
cod[] -- array of type Word16 -- algebraic (fixed) codebook excitation
Returns:
None
Global Variables Used:
None
Local Variables Needed:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
------------------------------------------------------------------------------
REQUIREMENTS
None
------------------------------------------------------------------------------
REFERENCES
d2_11pf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
------------------------------------------------------------------------------
RESOURCES USED [optional]
When the code is written for a specific target processor the
the resources used should be documented below.
HEAP MEMORY USED: x bytes
STACK MEMORY USED: x bytes
CLOCK CYCLES: (cycle count equation for this function) + (variable
used to represent cycle count for each subroutine
called)
where: (cycle count variable) = cycle count for [subroutine
name]
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
void decode_2i40_11bits(
Word16 sign, /* i : signs of 2 pulses. */
Word16 index, /* i : Positions of the 2 pulses. */
Word16 cod[] /* o : algebraic (fixed) codebook excitation */
)
{
Word16 i;
Word16 j;
Word16 pos[NB_PULSE];
/* Decode the positions */
j = index & 0x1;
index >>= 1;
i = index & 0x7;
pos[0] = i * 5 + j * 2 + 1;
index >>= 3;
j = index & 0x3;
index >>= 2;
i = index & 0x7;
if (j == 3)
{
pos[1] = i * 5 + 4;
}
else
{
pos[1] = i * 5 + j;
}
/* decode the signs and build the codeword */
for (i = 0; i < L_SUBFR; i++)
{
cod[i] = 0;
}
for (j = 0; j < NB_PULSE; j++)
{
i = sign & 1;
/* This line is equivalent to...
*
*
* if (i == 1)
* {
* cod[pos[j]] = 8191;
* }
* if (i == 0)
* {
* cod[pos[j]] = -8192;
* }
*/
cod[pos[j]] = i * 16383 - 8192;
sign >>= 1;
}
return;
}
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