1 /* ------------------------------------------------------------------
2 * Copyright (C) 1998-2009 PacketVideo
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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
14 * See the License for the specific language governing permissions
15 * and limitations under the License.
16 * -------------------------------------------------------------------
18 /****************************************************************************************
19 Portions of this file are derived from the following 3GPP standard:
22 ANSI-C code for the Adaptive Multi-Rate (AMR) speech codec
23 Available from http://www.3gpp.org
25 (C) 2004, 3GPP Organizational Partners (ARIB, ATIS, CCSA, ETSI, TTA, TTC)
26 Permission to distribute, modify and use this file under the standard license
27 terms listed above has been obtained from the copyright holder.
28 ****************************************************************************************/
30 ------------------------------------------------------------------------------
36 ------------------------------------------------------------------------------
40 Purpose : Scales the postfilter output on a subframe basis
41 : by automatic control of the subframe gain.
43 ------------------------------------------------------------------------------
49 /*----------------------------------------------------------------------------
51 ----------------------------------------------------------------------------*/
54 /*--------------------------------------------------------------------------*/
60 /*----------------------------------------------------------------------------
62 ; [Define module specific macros here]
63 ----------------------------------------------------------------------------*/
65 /*----------------------------------------------------------------------------
67 ; [Include all pre-processor statements here.]
68 ----------------------------------------------------------------------------*/
70 /*----------------------------------------------------------------------------
71 ; EXTERNAL VARIABLES REFERENCES
72 ; [Declare variables used in this module but defined elsewhere]
73 ----------------------------------------------------------------------------*/
75 /*----------------------------------------------------------------------------
77 ----------------------------------------------------------------------------*/
79 /*----------------------------------------------------------------------------
80 ; ENUMERATED TYPEDEF'S
81 ----------------------------------------------------------------------------*/
83 /*----------------------------------------------------------------------------
84 ; STRUCTURES TYPEDEF'S
85 ----------------------------------------------------------------------------*/
91 /*----------------------------------------------------------------------------
92 ; GLOBAL FUNCTION DEFINITIONS
93 ; [List function prototypes here]
94 ----------------------------------------------------------------------------*/
95 /*----------------------------------------------------------------------------
97 ; Function : agc_reset
98 ; Purpose : Reset of agc (i.e. set state memory to 1.0)
99 ; Returns : 0 on success
101 ----------------------------------------------------------------------------*/
102 Word16 agc_reset(agcState *st);
105 /*----------------------------------------------------------------------------
108 ; Purpose : Scales the postfilter output on a subframe basis
109 ; Description : sig_out[n] = sig_out[n] * gain[n];
110 ; where gain[n] is the gain at the nth sample given by
111 ; gain[n] = agc_fac * gain[n-1] + (1 - agc_fac) g_in/g_out
112 ; g_in/g_out is the square root of the ratio of energy at
113 ; the input and output of the postfilter.
115 ----------------------------------------------------------------------------*/
117 agcState *st, /* i/o : agc state */
118 Word16 *sig_in, /* i : postfilter input signal, (l_trm) */
119 Word16 *sig_out, /* i/o : postfilter output signal, (l_trm) */
120 Word16 agc_fac, /* i : AGC factor */
121 Word16 l_trm, /* i : subframe size */
122 Flag *pOverflow /* i : overflow flag */
125 /*----------------------------------------------------------------------------
128 ; Purpose: Scales the excitation on a subframe basis
130 ----------------------------------------------------------------------------*/
132 Word16 *sig_in, /* i : postfilter input signal */
133 Word16 *sig_out, /* i/o : postfilter output signal */
134 Word16 l_trm, /* i : subframe size */
135 Flag *pOverflow /* i : overflow flag */