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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/bgnscd.c
+ Functions:
+ Bgn_scd_reset
+ Bgn_scd
+
+------------------------------------------------------------------------------
+ MODULE DESCRIPTION
+
+ Background noise source characteristic detector (SCD)
+
+------------------------------------------------------------------------------
+*/
+
+
+/*----------------------------------------------------------------------------
+; INCLUDES
+----------------------------------------------------------------------------*/
+#include <string.h>
+
+#include "bgnscd.h"
+#include "typedef.h"
+#include "basic_op.h"
+#include "cnst.h"
+#include "copy.h"
+#include "gmed_n.h"
+#include "sqrt_l.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;
+}
+
+------------------------------------------------------------------------------
+ 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]
+
+------------------------------------------------------------------------------
+*/
+
+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 */
+ 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(&ltpGainHist[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;
+}
+
+------------------------------------------------------------------------------
+ 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]
+
+------------------------------------------------------------------------------
+*/
+
+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(&ltpGainHist[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);
+}
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