agc.h revision 4f1efc098cb5791c3e9f483f2af84aef70d2d0a0 
1/* ------------------------------------------------------------------
2 * Copyright (C) 1998-2009 PacketVideo
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
13 * express or implied.
14 * See the License for the specific language governing permissions
15 * and limitations under the License.
16 * -------------------------------------------------------------------
17 */
18/****************************************************************************************
19Portions of this file are derived from the following 3GPP standard:
20
21    3GPP TS 26.073
22    ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
23    Available from http://www.3gpp.org
24
25(C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
26Permission to distribute, modify and use this file under the standard license
27terms listed above has been obtained from the copyright holder.
28****************************************************************************************/
29/*
30------------------------------------------------------------------------------
31
32
33
34 Filename: /audio/gsm_amr/c/src/include/agc.h
35
36     Date: 12/07/2001
37
38------------------------------------------------------------------------------
39 REVISION HISTORY
40
41 Description: Removed unneeded sections of the standard template.
42              Updated function prototype for agc() and agc2() to match new
43              interface
44
45 Description: Changed paramter name from "overflow" to "pOverflow" for
46              functions agc() and agc2()
47
48 Description:  Replaced "int" and/or "char" with OSCL defined types.
49
50
51 Description: Moved _cplusplus #ifdef after Include section.
52
53 Description:
54
55------------------------------------------------------------------------------
56 INCLUDE DESCRIPTION
57
58      File             : agc.h
59      Purpose          : Scales the postfilter output on a subframe basis
60                       : by automatic control of the subframe gain.
61
62------------------------------------------------------------------------------
63*/
64
65#ifndef _AGC_H_
66#define _AGC_H_
67
68/*----------------------------------------------------------------------------
69; INCLUDES
70----------------------------------------------------------------------------*/
71#include "typedef.h"
72
73/*--------------------------------------------------------------------------*/
74#ifdef __cplusplus
75extern "C"
76{
77#endif
78
79    /*----------------------------------------------------------------------------
80    ; MACROS
81    ; [Define module specific macros here]
82    ----------------------------------------------------------------------------*/
83
84    /*----------------------------------------------------------------------------
85    ; DEFINES
86    ; [Include all pre-processor statements here.]
87    ----------------------------------------------------------------------------*/
88
89    /*----------------------------------------------------------------------------
90    ; EXTERNAL VARIABLES REFERENCES
91    ; [Declare variables used in this module but defined elsewhere]
92    ----------------------------------------------------------------------------*/
93
94    /*----------------------------------------------------------------------------
95    ; SIMPLE TYPEDEF'S
96    ----------------------------------------------------------------------------*/
97
98    /*----------------------------------------------------------------------------
99    ; ENUMERATED TYPEDEF'S
100    ----------------------------------------------------------------------------*/
101
102    /*----------------------------------------------------------------------------
103    ; STRUCTURES TYPEDEF'S
104    ----------------------------------------------------------------------------*/
105    typedef struct
106    {
107        Word16 past_gain;
108    } agcState;
109
110    /*----------------------------------------------------------------------------
111    ; GLOBAL FUNCTION DEFINITIONS
112    ; [List function prototypes here]
113    ----------------------------------------------------------------------------*/
114    /*----------------------------------------------------------------------------
115    ;
116    ;  Function    : agc_reset
117    ;  Purpose     : Reset of agc (i.e. set state memory to 1.0)
118    ;  Returns     : 0 on success
119    ;
120    ----------------------------------------------------------------------------*/
121    Word16 agc_reset(agcState *st);
122
123
124    /*----------------------------------------------------------------------------
125    ;
126    ;  Function    : agc
127    ;  Purpose     : Scales the postfilter output on a subframe basis
128    ;  Description : sig_out[n] = sig_out[n] * gain[n];
129    ;                where gain[n] is the gain at the nth sample given by
130    ;                gain[n] = agc_fac * gain[n-1] + (1 - agc_fac) g_in/g_out
131    ;                g_in/g_out is the square root of the ratio of energy at
132    ;                the input and output of the postfilter.
133    ;
134    ----------------------------------------------------------------------------*/
135    void agc(
136        agcState *st,      /* i/o : agc state                         */
137        Word16 *sig_in,    /* i   : postfilter input signal, (l_trm)  */
138        Word16 *sig_out,   /* i/o : postfilter output signal, (l_trm) */
139        Word16 agc_fac,    /* i   : AGC factor                        */
140        Word16 l_trm,      /* i   : subframe size                     */
141        Flag *pOverflow    /* i   : overflow flag                     */
142    );
143
144    /*----------------------------------------------------------------------------
145    ;
146    ;  Function:  agc2
147    ;  Purpose:   Scales the excitation on a subframe basis
148    ;
149    ----------------------------------------------------------------------------*/
150    void agc2(
151        Word16 *sig_in,    /* i   : postfilter input signal   */
152        Word16 *sig_out,   /* i/o : postfilter output signal  */
153        Word16 l_trm,      /* i   : subframe size             */
154        Flag *pOverflow    /* i   : overflow flag             */
155    );
156
157#ifdef __cplusplus
158}
159#endif
160
161#endif  /* _AGC_H_ */
162
163
164