164 lines
6.2 KiB
C
164 lines
6.2 KiB
C
/* ------------------------------------------------------------------
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* Copyright (C) 1998-2009 PacketVideo
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
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* express or implied.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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* -------------------------------------------------------------------
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*/
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/****************************************************************************************
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Portions of this file are derived from the following 3GPP standard:
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3GPP TS 26.073
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ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
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Available from http://www.3gpp.org
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(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
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Permission to distribute, modify and use this file under the standard license
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terms listed above has been obtained from the copyright holder.
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****************************************************************************************/
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/*
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------------------------------------------------------------------------------
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Filename: /audio/gsm_amr/c/src/include/agc.h
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Date: 12/07/2001
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------------------------------------------------------------------------------
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REVISION HISTORY
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Description: Removed unneeded sections of the standard template.
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Updated function prototype for agc() and agc2() to match new
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interface
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Description: Changed paramter name from "overflow" to "pOverflow" for
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functions agc() and agc2()
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Description: Replaced "int" and/or "char" with OSCL defined types.
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Description: Moved _cplusplus #ifdef after Include section.
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Description:
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------------------------------------------------------------------------------
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INCLUDE DESCRIPTION
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File : agc.h
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Purpose : Scales the postfilter output on a subframe basis
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: by automatic control of the subframe gain.
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------------------------------------------------------------------------------
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*/
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#ifndef _AGC_H_
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#define _AGC_H_
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/*----------------------------------------------------------------------------
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; INCLUDES
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----------------------------------------------------------------------------*/
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#include "typedef.h"
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/*--------------------------------------------------------------------------*/
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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/*----------------------------------------------------------------------------
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; MACROS
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; [Define module specific macros here]
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; DEFINES
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; [Include all pre-processor statements here.]
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; EXTERNAL VARIABLES REFERENCES
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; [Declare variables used in this module but defined elsewhere]
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; SIMPLE TYPEDEF'S
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; ENUMERATED TYPEDEF'S
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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; STRUCTURES TYPEDEF'S
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----------------------------------------------------------------------------*/
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typedef struct
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{
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Word16 past_gain;
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} agcState;
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/*----------------------------------------------------------------------------
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; GLOBAL FUNCTION DEFINITIONS
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; [List function prototypes here]
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----------------------------------------------------------------------------*/
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/*----------------------------------------------------------------------------
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;
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; Function : agc_reset
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; Purpose : Reset of agc (i.e. set state memory to 1.0)
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; Returns : 0 on success
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;
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----------------------------------------------------------------------------*/
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Word16 agc_reset(agcState *st);
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/*----------------------------------------------------------------------------
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;
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; Function : agc
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; Purpose : Scales the postfilter output on a subframe basis
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; Description : sig_out[n] = sig_out[n] * gain[n];
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; where gain[n] is the gain at the nth sample given by
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; gain[n] = agc_fac * gain[n-1] + (1 - agc_fac) g_in/g_out
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; g_in/g_out is the square root of the ratio of energy at
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; the input and output of the postfilter.
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;
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----------------------------------------------------------------------------*/
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void agc(
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agcState *st, /* i/o : agc state */
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Word16 *sig_in, /* i : postfilter input signal, (l_trm) */
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Word16 *sig_out, /* i/o : postfilter output signal, (l_trm) */
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Word16 agc_fac, /* i : AGC factor */
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Word16 l_trm, /* i : subframe size */
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Flag *pOverflow /* i : overflow flag */
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);
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/*----------------------------------------------------------------------------
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;
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; Function: agc2
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; Purpose: Scales the excitation on a subframe basis
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;
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----------------------------------------------------------------------------*/
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void agc2(
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Word16 *sig_in, /* i : postfilter input signal */
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Word16 *sig_out, /* i/o : postfilter output signal */
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Word16 l_trm, /* i : subframe size */
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Flag *pOverflow /* i : overflow flag */
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);
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#ifdef __cplusplus
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}
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#endif
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#endif /* _AGC_H_ */
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