msamr/opencore-amr/opencore/codecs_v2/audio/gsm_amr/amr_nb/dec/src/bgnscd.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: bgnscd.cpp
Functions:
Bgn_scd_reset
Bgn_scd
------------------------------------------------------------------------------
MODULE DESCRIPTION
Background noise source characteristic detector (SCD)
------------------------------------------------------------------------------
*/
/*----------------------------------------------------------------------------
; INCLUDES
----------------------------------------------------------------------------*/
#include "bgnscd.h"
#include "typedef.h"
#include "basic_op.h"
#include "cnst.h"
#include "gmed_n.h"
#include "sqrt_l.h"
#include "oscl_mem.h"
/*----------------------------------------------------------------------------
; MACROS
; Define module specific macros here
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; DEFINES
; Include all pre-processor statements here. Include conditional
; compile variables also.
----------------------------------------------------------------------------*/
#define TRUE 1
#define FALSE 0
/*----------------------------------------------------------------------------
; LOCAL FUNCTION DEFINITIONS
; Function Prototype declaration
----------------------------------------------------------------------------*/
/*----------------------------------------------------------------------------
; LOCAL VARIABLE DEFINITIONS
; Variable declaration - defined here and used outside this module
----------------------------------------------------------------------------*/
/*
------------------------------------------------------------------------------
FUNCTION NAME: Bgn_scd_reset
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
state = points to memory of type Bgn_scdState.
Outputs:
The memory of type Bgn_scdState pointed to by state is set to all
zeros.
Returns:
Returns 0 if memory was successfully initialized,
otherwise returns -1.
Global Variables Used:
None.
Local Variables Needed:
None.
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
Resets state memory.
------------------------------------------------------------------------------
REQUIREMENTS
None
------------------------------------------------------------------------------
REFERENCES
bgnscd.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
Word16 Bgn_scd_reset (Bgn_scdState *state)
{
if (state == (Bgn_scdState *) NULL){
fprintf(stderr, "Bgn_scd_reset: invalid parameter\n");
return -1;
}
// Static vectors to zero
Set_zero (state->frameEnergyHist, L_ENERGYHIST);
// Initialize hangover handling
state->bgHangover = 0;
return 0;
}
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
Word16 Bgn_scd_reset(Bgn_scdState *state)
{
if (state == (Bgn_scdState *) NULL)
{
/* fprintf(stderr, "Bgn_scd_reset: invalid parameter\n"); */
return(-1);
}
/* Static vectors to zero */
oscl_memset(state->frameEnergyHist, 0, L_ENERGYHIST*sizeof(Word16));
/* Initialize hangover handling */
state->bgHangover = 0;
return(0);
}
/****************************************************************************/
/*
------------------------------------------------------------------------------
FUNCTION NAME: Bgn_scd
------------------------------------------------------------------------------
INPUT AND OUTPUT DEFINITIONS
Inputs:
st = pointer to state variables of type Bgn_scdState
ltpGainHist[] = LTP gain history (Word16)
speech[] = synthesis speech frame (Word16)
voicedHangover = pointer to # of frames after last voiced frame (Word16)
pOverflow = pointer to overflow indicator (Flag)
Outputs:
st = function updates the state variables of type Bgn_scdState
pointed to by st.
voicedHangover = function updates the # of frames after last voiced
frame pointed to by voicedHangover.
pOverflow = 1 if the basic math function L_add() results in saturation.
else pOverflow is zero.
Returns:
inbgNoise = flag if background noise is present (Word16)
Global Variables Used:
None.
Local Variables Needed:
None.
------------------------------------------------------------------------------
FUNCTION DESCRIPTION
Characterize synthesis speech and detect background noise.
------------------------------------------------------------------------------
REQUIREMENTS
None
------------------------------------------------------------------------------
REFERENCES
bgnscd.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
------------------------------------------------------------------------------
PSEUDO-CODE
Word16 Bgn_scd (Bgn_scdState *st, // i : State variables for bgn SCD
Word16 ltpGainHist[], // i : LTP gain history
Word16 speech[], // o : synthesis speech frame
Word16 *voicedHangover // o : # of frames after last
voiced frame
)
{
Word16 i;
Word16 prevVoiced, inbgNoise;
Word16 temp;
Word16 ltpLimit, frameEnergyMin;
Word16 currEnergy, noiseFloor, maxEnergy, maxEnergyLastPart;
Word32 s;
// Update the inBackgroundNoise flag (valid for use in next frame if BFI)
// it now works as a energy detector floating on top
// not as good as a VAD.
currEnergy = 0;
s = (Word32) 0;
for (i = 0; i < L_FRAME; i++)
{
s = L_mac (s, speech[i], speech[i]);
}
s = L_shl(s, 2);
currEnergy = extract_h (s);
frameEnergyMin = 32767;
for (i = 0; i < L_ENERGYHIST; i++)
{
if (sub(st->frameEnergyHist[i], frameEnergyMin) < 0)
frameEnergyMin = st->frameEnergyHist[i];
}
noiseFloor = shl (frameEnergyMin, 4); // Frame Energy Margin of 16
maxEnergy = st->frameEnergyHist[0];
for (i = 1; i < L_ENERGYHIST-4; i++)
{
if ( sub (maxEnergy, st->frameEnergyHist[i]) < 0)
{
maxEnergy = st->frameEnergyHist[i];
}
}
maxEnergyLastPart = st->frameEnergyHist[2*L_ENERGYHIST/3];
for (i = 2*L_ENERGYHIST/3+1; i < L_ENERGYHIST; i++)
{
if ( sub (maxEnergyLastPart, st->frameEnergyHist[i] ) < 0)
{
maxEnergyLastPart = st->frameEnergyHist[i];
}
}
inbgNoise = 0; // false
// Do not consider silence as noise
// Do not consider continuous high volume as noise
// Or if the current noise level is very low
// Mark as noise if under current noise limit
// OR if the maximum energy is below the upper limit
if ( (sub(maxEnergy, LOWERNOISELIMIT) > 0) &&
(sub(currEnergy, FRAMEENERGYLIMIT) < 0) &&
(sub(currEnergy, LOWERNOISELIMIT) > 0) &&
( (sub(currEnergy, noiseFloor) < 0) ||
(sub(maxEnergyLastPart, UPPERNOISELIMIT) < 0)))
{
if (sub(add(st->bgHangover, 1), 30) > 0)
{
st->bgHangover = 30;
} else
{
st->bgHangover = add(st->bgHangover, 1);
}
}
else
{
st->bgHangover = 0;
}
// make final decision about frame state , act somewhat cautiosly
if (sub(st->bgHangover,1) > 0)
inbgNoise = 1; // true
for (i = 0; i < L_ENERGYHIST-1; i++)
{
st->frameEnergyHist[i] = st->frameEnergyHist[i+1];
}
st->frameEnergyHist[L_ENERGYHIST-1] = currEnergy;
// prepare for voicing decision; tighten the threshold after some
time in noise
ltpLimit = 13926; // 0.85 Q14
if (sub(st->bgHangover, 8) > 0)
{
ltpLimit = 15565; // 0.95 Q14
}
if (sub(st->bgHangover, 15) > 0)
{
ltpLimit = 16383; // 1.00 Q14
}
// weak sort of voicing indication.
prevVoiced = 0; // false
if (sub(gmed_n(<pGainHist[4], 5), ltpLimit) > 0)
{
prevVoiced = 1; // true
}
if (sub(st->bgHangover, 20) > 0) {
if (sub(gmed_n(ltpGainHist, 9), ltpLimit) > 0)
{
prevVoiced = 1; // true
}
else
{
prevVoiced = 0; // false
}
}
if (prevVoiced)
{
*voicedHangover = 0;
}
else
{
temp = add(*voicedHangover, 1);
if (sub(temp, 10) > 0)
{
*voicedHangover = 10;
}
else
{
*voicedHangover = temp;
}
}
return inbgNoise;
}
------------------------------------------------------------------------------
CAUTION [optional]
[State any special notes, constraints or cautions for users of this function]
------------------------------------------------------------------------------
*/
Word16 Bgn_scd(Bgn_scdState *st, /* i : State variables for bgn SCD */
Word16 ltpGainHist[], /* i : LTP gain history */
Word16 speech[], /* o : synthesis speech frame */
Word16 *voicedHangover,/* o : # of frames after last
voiced frame */
Flag *pOverflow
)
{
Word16 i;
Word16 prevVoiced, inbgNoise;
Word16 temp;
Word16 ltpLimit, frameEnergyMin;
Word16 currEnergy, noiseFloor, maxEnergy, maxEnergyLastPart;
Word32 s, L_temp;
/* Update the inBackgroundNoise flag (valid for use in next frame if BFI) */
/* it now works as a energy detector floating on top */
/* not as good as a VAD. */
s = (Word32) 0;
for (i = L_FRAME - 1; i >= 0; i--)
{
L_temp = ((Word32) speech[i]) * speech[i];
if (L_temp != (Word32) 0x40000000L)
{
L_temp = L_temp << 1;
}
else
{
L_temp = MAX_32;
}
s = L_add(s, L_temp, pOverflow);
}
/* s is a sum of squares, so don't need to check for neg overflow */
if (s > (Word32)0x1fffffffL)
{
currEnergy = MAX_16;
}
else
{
currEnergy = (Word16)(s >> 14);
}
frameEnergyMin = 32767;
for (i = L_ENERGYHIST - 1; i >= 0; i--)
{
if (st->frameEnergyHist[i] < frameEnergyMin)
{
frameEnergyMin = st->frameEnergyHist[i];
}
}
/* Frame Energy Margin of 16 */
L_temp = (Word32)frameEnergyMin << 4;
if (L_temp != (Word32)((Word16) L_temp))
{
if (L_temp > 0)
{
noiseFloor = MAX_16;
}
else
{
noiseFloor = MIN_16;
}
}
else
{
noiseFloor = (Word16)(L_temp);
}
maxEnergy = st->frameEnergyHist[0];
for (i = L_ENERGYHIST - 5; i >= 1; i--)
{
if (maxEnergy < st->frameEnergyHist[i])
{
maxEnergy = st->frameEnergyHist[i];
}
}
maxEnergyLastPart = st->frameEnergyHist[2*L_ENERGYHIST/3];
for (i = 2 * L_ENERGYHIST / 3 + 1; i < L_ENERGYHIST; i++)
{
if (maxEnergyLastPart < st->frameEnergyHist[i])
{
maxEnergyLastPart = st->frameEnergyHist[i];
}
}
/* Do not consider silence as noise */
/* Do not consider continuous high volume as noise */
/* Or if the current noise level is very low */
/* Mark as noise if under current noise limit */
/* OR if the maximum energy is below the upper limit */
if ((maxEnergy > LOWERNOISELIMIT) &&
(currEnergy < FRAMEENERGYLIMIT) &&
(currEnergy > LOWERNOISELIMIT) &&
((currEnergy < noiseFloor) ||
(maxEnergyLastPart < UPPERNOISELIMIT)))
{
if ((st->bgHangover + 1) > 30)
{
st->bgHangover = 30;
}
else
{
st->bgHangover += 1;
}
}
else
{
st->bgHangover = 0;
}
/* make final decision about frame state , act somewhat cautiosly */
if (st->bgHangover > 1)
{
inbgNoise = TRUE;
}
else
{
inbgNoise = FALSE;
}
for (i = 0; i < L_ENERGYHIST - 1; i++)
{
st->frameEnergyHist[i] = st->frameEnergyHist[i+1];
}
st->frameEnergyHist[L_ENERGYHIST-1] = currEnergy;
/* prepare for voicing decision; tighten the threshold after some
time in noise */
if (st->bgHangover > 15)
{
ltpLimit = 16383; /* 1.00 Q14 */
}
else if (st->bgHangover > 8)
{
ltpLimit = 15565; /* 0.95 Q14 */
}
else
{
ltpLimit = 13926; /* 0.85 Q14 */
}
/* weak sort of voicing indication. */
prevVoiced = FALSE;
if (gmed_n(<pGainHist[4], 5) > ltpLimit)
{
prevVoiced = TRUE;
}
if (st->bgHangover > 20)
{
if (gmed_n(ltpGainHist, 9) > ltpLimit)
{
prevVoiced = TRUE;
}
else
{
prevVoiced = FALSE;
}
}
if (prevVoiced)
{
*voicedHangover = 0;
}
else
{
temp = *voicedHangover + 1;
if (temp > 10)
{
*voicedHangover = 10;
}
else
{
*voicedHangover = temp;
}
}
return(inbgNoise);
}