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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.
****************************************************************************************/
/*
Filename: lflg_upd.cpp
Functions: LTP_flag_update
------------------------------------------------------------------------------
MODULE DESCRIPTION
LTP_flag update for AMR VAD option 2
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "typedef.h"
#include "cnst.h"
#include "l_extract.h"
#include "mpy_32_16.h"
#include "vad2.h"
#include "mode.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 VARIABLE DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
/*
------------------------------------------------------------------------------
FUNCTION NAME:
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
st -- Pointer to vadState2
mode -- Word16 -- AMR mode
Outputs:
st -- Pointer to vadState2
pOverflow -- Pointer to Flag -- overflow indicator
Returns:
None
Global Variables Used:
None
Local Variables Needed:
None
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
LTP_flag update for AMR VAD option 2
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
------------------------------------------------------------------------------
REQUIREMENTS
None
------------------------------------------------------------------------------
REFERENCES
lflg_upd.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
void LTP_flag_update(
vadState2 * st,
Word16 mode,
Flag *pOverflow)
{
Word16 thresh;
Word16 hi1;
Word16 lo1;
Word32 Ltmp;
if ((mode == MR475) || (mode == MR515))
{
thresh = 18022; /* (Word16)(32768.0*0.55); */
}
else if (mode == MR102)
{
thresh = 19660; /* (Word16)(32768.0*0.60); */
}
else
{
thresh = 21299; /* (Word16)(32768.0*0.65); */
}
L_Extract(st->L_R0, &hi1, &lo1, pOverflow);
Ltmp = Mpy_32_16(hi1, lo1, thresh, pOverflow);
if (st->L_Rmax > Ltmp)
{
st->LTP_flag = TRUE;
}
else
{
st->LTP_flag = FALSE;
}
return;
}
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