| /* ------------------------------------------------------------------ |
| * 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/agc.c |
| Funtions: energy_old |
| energy_new |
| agc_init |
| agc_reset |
| agc_exit |
| agc |
| agc2 |
| |
| ------------------------------------------------------------------------------ |
| MODULE DESCRIPTION |
| |
| This set of modules scale the excitation level and output of the speech |
| signals. |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| |
| /*---------------------------------------------------------------------------- |
| ; INCLUDES |
| ----------------------------------------------------------------------------*/ |
| |
| #include "agc.h" |
| #include "cnst.h" |
| #include "inv_sqrt.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 VARIABLE DEFINITIONS |
| ; Variable declaration - defined here and used outside this module |
| ----------------------------------------------------------------------------*/ |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: energy_old |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| in = input signal (Word16) |
| l_trm = input signal length (Word16) |
| pOverflow = address of overflow (Flag) |
| |
| Outputs: |
| pOverflow -> 1 if the energy computation saturates |
| |
| Returns: |
| s = return energy of signal (Word32) |
| |
| Global Variables Used: |
| None. |
| |
| Local Variables Needed: |
| None. |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Returns the energy of the signal. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None. |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| agc.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| static Word32 energy_old( // o : return energy of signal |
| Word16 in[], // i : input signal (length l_trm) |
| Word16 l_trm // i : signal length |
| ) |
| { |
| Word32 s; |
| Word16 i, temp; |
| |
| temp = shr (in[0], 2); |
| s = L_mult (temp, temp); |
| |
| for (i = 1; i < l_trm; i++) |
| { |
| temp = shr (in[i], 2); |
| s = L_mac (s, temp, temp); |
| } |
| |
| return s; |
| } |
| |
| ------------------------------------------------------------------------------ |
| 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] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| static Word32 energy_old( /* o : return energy of signal */ |
| Word16 in[], /* i : input signal (length l_trm) */ |
| Word16 l_trm, /* i : signal length */ |
| Flag *pOverflow /* overflow: flag to indicate overflow */ |
| ) |
| |
| { |
| Word32 s = 0; |
| Word16 i; |
| Word16 temp; |
| |
| for (i = 0; i < l_trm; i++) |
| { |
| temp = in[i] >> 2; |
| s = L_mac(s, temp, temp, pOverflow); |
| } |
| |
| return(s); |
| } |
| |
| /*----------------------------------------------------------------------------*/ |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: energy_old__Wrapper |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| in = input signal (Word16) |
| l_trm = input signal length (Word16) |
| pOverflow = address of overflow (Flag) |
| Outputs: |
| pOverflow -> 1 if the energy computation saturates |
| |
| Returns: |
| s = return energy of signal (Word32) |
| |
| Global Variables Used: |
| None. |
| |
| Local Variables Needed: |
| None. |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function provides external access to the static function energy_old. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| CALL energy_old ( in = in |
| l_trm = l_trm |
| pOverflow = pOverflow ) |
| MODIFYING(nothing) |
| RETURNING(energy_old_value = s) |
| |
| ------------------------------------------------------------------------------ |
| 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] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| Word32 energy_old_Wrapper(Word16 in[], Word16 l_trm, Flag *pOverflow) |
| { |
| Word32 energy_old_value; |
| |
| /*---------------------------------------------------------------------------- |
| CALL energy_old ( in = in |
| l_trm = l_trm |
| pOverflow = pOverflow ) |
| |
| MODIFYING(nothing) |
| RETURNING(energy_old_value = s) |
| ----------------------------------------------------------------------------*/ |
| energy_old_value = energy_old(in, l_trm, pOverflow); |
| return(energy_old_value); |
| } |
| /*--------------------------------------------------------------------------*/ |
| |
| /* |
| ----------------------------------------------------------------------------- |
| FUNCTION NAME: energy_new |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| in = input signal |
| l_trm = input signal length |
| pOverflow = address of overflow (Flag) |
| |
| Outputs: |
| pOverflow -> 1 if the energy computation saturates |
| |
| Returns: |
| s = return energy of signal |
| |
| Global Variables Used: |
| None. |
| |
| Local Variables Needed: |
| None. |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Returns the energy of the signal. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None. |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| agc.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| static Word32 energy_new( // o : return energy of signal |
| Word16 in[], // i : input signal (length l_trm) |
| Word16 l_trm ) // i : signal length |
| |
| { |
| Word32 s; |
| Word16 i; |
| Flag ov_save; |
| |
| ov_save = Overflow; //save overflow flag in case energy_old |
| // must be called |
| s = L_mult(in[0], in[0]); |
| for (i = 1; i < l_trm; i++) |
| { |
| s = L_mac(s, in[i], in[i]); |
| } |
| |
| // check for overflow |
| if (L_sub (s, MAX_32) == 0L) |
| { |
| Overflow = ov_save; // restore overflow flag |
| s = energy_old (in, l_trm); // function result |
| } |
| else |
| { |
| s = L_shr(s, 4); |
| } |
| |
| return(s); |
| } |
| |
| ------------------------------------------------------------------------------ |
| 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] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| static Word32 energy_new( /* o : return energy of signal */ |
| Word16 in[], /* i : input signal (length l_trm) */ |
| Word16 l_trm, /* i : signal length */ |
| Flag *pOverflow /* i : overflow flag */ |
| ) |
| |
| { |
| Word32 s = 0; |
| Word16 i; |
| Flag ov_save; |
| |
| ov_save = *(pOverflow); /* save overflow flag in case energy_old */ |
| /* must be called */ |
| |
| |
| for (i = 0; i < l_trm; i++) |
| { |
| s = L_mac(s, in[i], in[i], pOverflow); |
| } |
| |
| /* check for overflow */ |
| if (s != MAX_32) |
| { |
| /* s is a sum of squares, so it won't be negative */ |
| s = s >> 4; |
| } |
| else |
| { |
| *(pOverflow) = ov_save; /* restore overflow flag */ |
| s = energy_old(in, l_trm, pOverflow); /* function result */ |
| } |
| |
| return (s); |
| } |
| |
| /*--------------------------------------------------------------------------*/ |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: energy_new__Wrapper |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| in = input signal (Word16) |
| l_trm = input signal length (Word16) |
| overflow = address of overflow (Flag) |
| |
| Outputs: |
| pOverflow -> 1 if the energy computation saturates |
| |
| Returns: |
| s = return energy of signal (Word32) |
| |
| Global Variables Used: |
| None. |
| |
| Local Variables Needed: |
| None. |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| This function provides external access to the static function energy_new. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| None |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| CALL energy_new ( in = in |
| l_trm = l_trm |
| pOverflow = pOverflow ) |
| |
| MODIFYING(nothing) |
| |
| RETURNING(energy_new_value = s) |
| |
| ------------------------------------------------------------------------------ |
| 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] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| Word32 energy_new_Wrapper(Word16 in[], Word16 l_trm, Flag *pOverflow) |
| { |
| Word32 energy_new_value; |
| |
| /*---------------------------------------------------------------------------- |
| CALL energy_new ( in = in |
| l_trm = l_trm |
| pOverflow = pOverflow ) |
| |
| MODIFYING(nothing) |
| RETURNING(energy_new_value = s) |
| |
| ----------------------------------------------------------------------------*/ |
| energy_new_value = energy_new(in, l_trm, pOverflow); |
| |
| return(energy_new_value); |
| |
| } |
| |
| /*--------------------------------------------------------------------------*/ |
| |
| |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: agc_reset |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| state = pointer to a structure of type agcState |
| |
| Outputs: |
| Structure pointed to by state is initialized to zeros |
| |
| Returns: |
| Returns 0 if memory was successfully initialized, |
| otherwise returns -1. |
| |
| Global Variables Used: |
| None. |
| |
| Local Variables Needed: |
| None. |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Reset of agc (i.e. set state memory to 1.0). |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None. |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| agc.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| int agc_reset (agcState *state) |
| { |
| if (state == (agcState *) NULL) |
| { |
| fprintf(stderr, "agc_reset: invalid parameter\n"); |
| return -1; |
| } |
| |
| state->past_gain = 4096; // initial value of past_gain = 1.0 |
| |
| 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 agc_reset(agcState *state) |
| { |
| if (state == (agcState *) NULL) |
| { |
| /* fprintf(stderr, "agc_reset: invalid parameter\n"); */ |
| return(-1); |
| } |
| |
| state->past_gain = 4096; /* initial value of past_gain = 1.0 */ |
| |
| return(0); |
| } |
| |
| /*--------------------------------------------------------------------------*/ |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: agc |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| st = pointer to agc state |
| sig_in = pointer to a buffer containing the postfilter input signal |
| sig_out = pointer to a buffer containing the postfilter output signal |
| agc_fac = AGC factor |
| l_trm = subframe size |
| pOverflow = pointer to the overflow flag |
| |
| Outputs: |
| st->past_gain = gain |
| buffer pointed to by sig_out contains the new postfilter output signal |
| pOverflow -> 1 if the agc computation saturates |
| |
| Returns: |
| return = 0 |
| |
| Global Variables Used: |
| none. |
| |
| Local Variables Needed: |
| none. |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Scales the postfilter output on a subframe basis using: |
| |
| sig_out[n] = sig_out[n] * gain[n] |
| gain[n] = agc_fac * gain[n-1] + (1 - agc_fac) g_in/g_out |
| |
| where: gain[n] = gain at the nth sample given by |
| g_in/g_out = square root of the ratio of energy at |
| the input and output of the postfilter. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None. |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| agc.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| int agc ( |
| agcState *st, // i/o : agc state |
| Word16 *sig_in, // i : postfilter input signal (l_trm) |
| Word16 *sig_out, // i/o : postfilter output signal (l_trm) |
| Word16 agc_fac, // i : AGC factor |
| Word16 l_trm // i : subframe size |
| ) |
| { |
| Word16 i, exp; |
| Word16 gain_in, gain_out, g0, gain; |
| Word32 s; |
| |
| // calculate gain_out with exponent |
| s = energy_new(sig_out, l_trm); // function result |
| |
| if (s == 0) |
| { |
| st->past_gain = 0; |
| return 0; |
| } |
| exp = sub (norm_l (s), 1); |
| gain_out = pv_round (L_shl (s, exp)); |
| |
| // calculate gain_in with exponent |
| s = energy_new(sig_in, l_trm); // function result |
| |
| if (s == 0) |
| { |
| g0 = 0; |
| } |
| else |
| { |
| i = norm_l (s); |
| gain_in = pv_round (L_shl (s, i)); |
| exp = sub (exp, i); |
| |
| *---------------------------------------------------* |
| * g0 = (1-agc_fac) * sqrt(gain_in/gain_out); * |
| *---------------------------------------------------* |
| |
| s = L_deposit_l (div_s (gain_out, gain_in)); |
| s = L_shl (s, 7); // s = gain_out / gain_in |
| s = L_shr (s, exp); // add exponent |
| |
| s = Inv_sqrt (s); // function result |
| i = pv_round (L_shl (s, 9)); |
| |
| // g0 = i * (1-agc_fac) |
| g0 = mult (i, sub (32767, agc_fac)); |
| } |
| |
| // compute gain[n] = agc_fac * gain[n-1] |
| + (1-agc_fac) * sqrt(gain_in/gain_out) |
| // sig_out[n] = gain[n] * sig_out[n] |
| |
| gain = st->past_gain; |
| |
| for (i = 0; i < l_trm; i++) |
| { |
| gain = mult (gain, agc_fac); |
| gain = add (gain, g0); |
| sig_out[i] = extract_h (L_shl (L_mult (sig_out[i], gain), 3)); |
| } |
| |
| st->past_gain = gain; |
| |
| 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] |
| |
| ------------------------------------------------------------------------------ |
| */ |
| |
| void agc( |
| agcState *st, /* i/o : agc state */ |
| Word16 *sig_in, /* i : postfilter input signal (l_trm) */ |
| Word16 *sig_out, /* i/o : postfilter output signal (l_trm) */ |
| Word16 agc_fac, /* i : AGC factor */ |
| Word16 l_trm, /* i : subframe size */ |
| Flag *pOverflow /* i : overflow Flag */ |
| |
| ) |
| |
| { |
| Word16 i; |
| Word16 exp; |
| Word16 gain_in; |
| Word16 gain_out; |
| Word16 g0; |
| Word16 gain; |
| Word32 s; |
| Word32 L_temp; |
| Word16 temp; |
| |
| Word16 *p_sig_out; |
| |
| /* calculate gain_out with exponent */ |
| s = energy_new(sig_out, l_trm, pOverflow); /* function result */ |
| |
| if (s == 0) |
| { |
| st->past_gain = 0; |
| return; |
| } |
| exp = norm_l(s) - 1; |
| |
| L_temp = L_shl(s, exp, pOverflow); |
| gain_out = pv_round(L_temp, pOverflow); |
| |
| /* calculate gain_in with exponent */ |
| s = energy_new(sig_in, l_trm, pOverflow); /* function result */ |
| |
| if (s == 0) |
| { |
| g0 = 0; |
| } |
| else |
| { |
| i = norm_l(s); |
| |
| /* L_temp = L_shl(s, i, pOverflow); */ |
| L_temp = s << i; |
| |
| gain_in = pv_round(L_temp, pOverflow); |
| |
| exp -= i; |
| |
| /*---------------------------------------------------* |
| * g0 = (1-agc_fac) * sqrt(gain_in/gain_out); * |
| *---------------------------------------------------*/ |
| |
| /* s = gain_out / gain_in */ |
| temp = div_s(gain_out, gain_in); |
| |
| /* s = L_deposit_l (temp); */ |
| s = (Word32) temp; |
| s = s << 7; |
| s = L_shr(s, exp, pOverflow); /* add exponent */ |
| |
| s = Inv_sqrt(s, pOverflow); /* function result */ |
| L_temp = s << 9; |
| |
| i = (Word16)((L_temp + (Word32) 0x00008000L) >> 16); |
| |
| /* g0 = i * (1-agc_fac) */ |
| temp = 32767 - agc_fac; |
| |
| g0 = (Word16)(((Word32) i * temp) >> 15); |
| |
| } |
| |
| /* compute gain[n] = agc_fac * gain[n-1] |
| + (1-agc_fac) * sqrt(gain_in/gain_out) */ |
| /* sig_out[n] = gain[n] * sig_out[n] */ |
| |
| gain = st->past_gain; |
| p_sig_out = sig_out; |
| |
| for (i = 0; i < l_trm; i++) |
| { |
| /* gain = mult (gain, agc_fac, pOverflow); */ |
| gain = (Word16)(((Word32) gain * agc_fac) >> 15); |
| |
| /* gain = add (gain, g0, pOverflow); */ |
| gain += g0; |
| |
| /* L_temp = L_mult (sig_out[i], gain, pOverflow); */ |
| L_temp = ((Word32)(*(p_sig_out)) * gain) << 1; |
| |
| *(p_sig_out++) = (Word16)(L_temp >> 13); |
| } |
| |
| st->past_gain = gain; |
| |
| return; |
| } |
| |
| /*--------------------------------------------------------------------------*/ |
| |
| /* |
| ------------------------------------------------------------------------------ |
| FUNCTION NAME: agc2 |
| ------------------------------------------------------------------------------ |
| INPUT AND OUTPUT DEFINITIONS |
| |
| Inputs: |
| sig_in = pointer to a buffer containing the postfilter input signal |
| sig_out = pointer to a buffer containing the postfilter output signal |
| l_trm = subframe size |
| pOverflow = pointer to overflow flag |
| |
| Outputs: |
| sig_out points to a buffer containing the new scaled output signal. |
| pOverflow -> 1 if the agc computation saturates |
| |
| Returns: |
| None. |
| |
| Global Variables Used: |
| None. |
| |
| Local Variables Needed: |
| None. |
| |
| ------------------------------------------------------------------------------ |
| FUNCTION DESCRIPTION |
| |
| Scales the excitation on a subframe basis. |
| |
| ------------------------------------------------------------------------------ |
| REQUIREMENTS |
| |
| None. |
| |
| ------------------------------------------------------------------------------ |
| REFERENCES |
| |
| agc.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001 |
| |
| ------------------------------------------------------------------------------ |
| PSEUDO-CODE |
| |
| void agc2 ( |
| Word16 *sig_in, // i : postfilter input signal |
| Word16 *sig_out, // i/o : postfilter output signal |
| Word16 l_trm // i : subframe size |
| ) |
| { |
| Word16 i, exp; |
| Word16 gain_in, gain_out, g0; |
| Word32 s; |
| |
| // calculate gain_out with exponent |
| s = energy_new(sig_out, l_trm); // function result |
| |
| if (s == 0) |
| { |
| return; |
| } |
| exp = sub (norm_l (s), 1); |
| gain_out = pv_round (L_shl (s, exp)); |
| |
| // calculate gain_in with exponent |
| s = energy_new(sig_in, l_trm); // function result |
| |
| if (s == 0) |
| { |
| g0 = 0; |
| } |
| else |
| { |
| i = norm_l (s); |
| gain_in = pv_round (L_shl (s, i)); |
| exp = sub (exp, i); |
| |
| *---------------------------------------------------* |
| * g0 = sqrt(gain_in/gain_out); * |
| *---------------------------------------------------* |
| |
| s = L_deposit_l (div_s (gain_out, gain_in)); |
| s = L_shl (s, 7); // s = gain_out / gain_in |
| s = L_shr (s, exp); // add exponent |
| |
| s = Inv_sqrt (s); // function result |
| g0 = pv_round (L_shl (s, 9)); |
| } |
| |
| // sig_out(n) = gain(n) sig_out(n) |
| |
| for (i = 0; i < l_trm; i++) |
| { |
| sig_out[i] = extract_h (L_shl (L_mult (sig_out[i], g0), 3)); |
| } |
| |
| return; |
| } |
| ------------------------------------------------------------------------------ |
| 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 agc2( |
| Word16 *sig_in, /* i : postfilter input signal */ |
| Word16 *sig_out, /* i/o : postfilter output signal */ |
| Word16 l_trm, /* i : subframe size */ |
| Flag *pOverflow /* i : overflow flag */ |
| ) |
| |
| { |
| Word16 i; |
| Word16 exp; |
| Word16 gain_in; |
| Word16 gain_out; |
| Word16 g0; |
| Word32 s; |
| Word32 L_temp; |
| Word16 temp; |
| |
| /* calculate gain_out with exponent */ |
| s = energy_new(sig_out, l_trm, pOverflow); /* function result */ |
| |
| if (s == 0) |
| { |
| return; |
| } |
| exp = norm_l(s) - 1; |
| L_temp = L_shl(s, exp, pOverflow); |
| gain_out = pv_round(L_temp, pOverflow); |
| |
| /* calculate gain_in with exponent */ |
| s = energy_new(sig_in, l_trm, pOverflow); /* function result */ |
| |
| if (s == 0) |
| { |
| g0 = 0; |
| } |
| else |
| { |
| i = norm_l(s); |
| L_temp = L_shl(s, i, pOverflow); |
| gain_in = pv_round(L_temp, pOverflow); |
| exp -= i; |
| |
| /*---------------------------------------------------* |
| * g0 = sqrt(gain_in/gain_out); * |
| *---------------------------------------------------*/ |
| |
| /* s = gain_out / gain_in */ |
| temp = div_s(gain_out, gain_in); |
| |
| /* s = L_deposit_l (temp); */ |
| s = (Word32)temp; |
| |
| if (s > (Word32) 0x00FFFFFFL) |
| { |
| s = MAX_32; |
| } |
| else if (s < (Word32) 0xFF000000L) |
| { |
| s = MIN_32; |
| } |
| else |
| { |
| s = s << 7; |
| } |
| s = L_shr(s, exp, pOverflow); /* add exponent */ |
| |
| s = Inv_sqrt(s, pOverflow); /* function result */ |
| |
| if (s > (Word32) 0x003FFFFFL) |
| { |
| L_temp = MAX_32; |
| } |
| else if (s < (Word32) 0xFFC00000L) |
| { |
| L_temp = MIN_32; |
| } |
| else |
| { |
| L_temp = s << 9; |
| } |
| g0 = pv_round(L_temp, pOverflow); |
| } |
| |
| /* sig_out(n) = gain(n) sig_out(n) */ |
| |
| for (i = l_trm - 1; i >= 0; i--) |
| { |
| L_temp = L_mult(sig_out[i], g0, pOverflow); |
| if (L_temp > (Word32) 0x0FFFFFFFL) |
| { |
| sig_out[i] = MAX_16; |
| } |
| else if (L_temp < (Word32) 0xF0000000L) |
| { |
| sig_out[i] = MIN_16; |
| } |
| else |
| { |
| sig_out[i] = (Word16)(L_temp >> 13); |
| } |
| } |
| |
| return; |
| } |
