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 /****************************************************************************************
19 Portions of this file are derived from the following 3GPP standard:
20
21 3GPP TS 26.173
22 ANSI-C code for the Adaptive Multi-Rate - Wideband (AMR-WB) speech codec
23 Available from http://www.3gpp.org
24
25 (C) 2007, 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 ****************************************************************************************/
29 /*
30 ------------------------------------------------------------------------------
31
32
33
34 Filename: preemph_amrwb_dec.cpp
35
36 Date: 12/10/2004
37
38 ------------------------------------------------------------------------------
39 REVISION HISTORY
40
41
42 Description:
43
44 ------------------------------------------------------------------------------
45 INPUT AND OUTPUT DEFINITIONS
46
47 int16 x[], (i/o) : input signal overwritten by the output
48 int16 mu, (i) Q15 : preemphasis coefficient
49 int16 lg (i) : lenght of filtering
50
51 ------------------------------------------------------------------------------
52 FUNCTION DESCRIPTION
53
54 Preemphasis: filtering through 1 - g z^-1
55
56 ------------------------------------------------------------------------------
57 REQUIREMENTS
58
59
60 ------------------------------------------------------------------------------
61 REFERENCES
62
63 ------------------------------------------------------------------------------
64 PSEUDO-CODE
65
66 ------------------------------------------------------------------------------
67 */
68
69 /*----------------------------------------------------------------------------
70 ; INCLUDES
71 ----------------------------------------------------------------------------*/
72
73 #include "pv_amr_wb_type_defs.h"
74 #include "pvamrwbdecoder_basic_op.h"
75 #include "pvamrwbdecoder_acelp.h"
76
77 /*----------------------------------------------------------------------------
78 ; MACROS
79 ; Define module specific macros here
80 ----------------------------------------------------------------------------*/
81
82
83 /*----------------------------------------------------------------------------
84 ; DEFINES
85 ; Include all pre-processor statements here. Include conditional
86 ; compile variables also.
87 ----------------------------------------------------------------------------*/
88
89 /*----------------------------------------------------------------------------
90 ; LOCAL FUNCTION DEFINITIONS
91 ; Function Prototype declaration
92 ----------------------------------------------------------------------------*/
93
94 /*----------------------------------------------------------------------------
95 ; LOCAL STORE/BUFFER/POINTER DEFINITIONS
96 ; Variable declaration - defined here and used outside this module
97 ----------------------------------------------------------------------------*/
98
99 /*----------------------------------------------------------------------------
100 ; EXTERNAL FUNCTION REFERENCES
101 ; Declare functions defined elsewhere and referenced in this module
102 ----------------------------------------------------------------------------*/
103
104 /*----------------------------------------------------------------------------
105 ; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
106 ; Declare variables used in this module but defined elsewhere
107 ----------------------------------------------------------------------------*/
108
109 /*----------------------------------------------------------------------------
110 ; FUNCTION CODE
111 ----------------------------------------------------------------------------*/
112
113
preemph_amrwb_dec(int16 x[],int16 mu,int16 lg)114 void preemph_amrwb_dec(
115 int16 x[], /* (i/o) : input signal overwritten by the output */
116 int16 mu, /* (i) Q15 : preemphasis coefficient */
117 int16 lg /* (i) : lenght of filtering */
118 )
119 {
120 int16 i;
121 int32 L_tmp;
122
123 for (i = lg - 1; i != 0; i--)
124 {
125 L_tmp = msu_16by16_from_int32((int32)x[i] << 16, x[i - 1], mu);
126 x[i] = amr_wb_round(L_tmp);
127 }
128
129 }
130
131