isp_isf.cpp 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 26.173
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)
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: isp_isf.cpp
35
36     Date: 05/08/2004
37
38------------------------------------------------------------------------------
39 REVISION HISTORY
40
41
42 Description:
43
44------------------------------------------------------------------------------
45 INPUT AND OUTPUT DEFINITIONS
46
47     int16 isf[],       (i) Q15 : isf[m] normalized (range: 0.0<=val<=0.5)
48     int16 isp[],       (o) Q15 : isp[m] (range: -1<=val<1)
49     int16 m            (i)     : LPC order
50
51
52------------------------------------------------------------------------------
53 FUNCTION DESCRIPTION
54
55     Isf_isp   Transformation isf to isp
56
57   The transformation from isf[i] to isp[i] is
58   approximated by a look-up table and interpolation.
59
60
61
62------------------------------------------------------------------------------
63 REQUIREMENTS
64
65
66------------------------------------------------------------------------------
67 REFERENCES
68
69------------------------------------------------------------------------------
70 PSEUDO-CODE
71
72------------------------------------------------------------------------------
73*/
74
75
76/*----------------------------------------------------------------------------
77; INCLUDES
78----------------------------------------------------------------------------*/
79
80
81#include "pv_amr_wb_type_defs.h"
82#include "pvamrwbdecoder_basic_op.h"
83#include "pvamrwbdecoder_acelp.h"
84
85/*----------------------------------------------------------------------------
86; MACROS
87; Define module specific macros here
88----------------------------------------------------------------------------*/
89
90
91/*----------------------------------------------------------------------------
92; DEFINES
93; Include all pre-processor statements here. Include conditional
94; compile variables also.
95----------------------------------------------------------------------------*/
96
97/*----------------------------------------------------------------------------
98; LOCAL FUNCTION DEFINITIONS
99; Function Prototype declaration
100----------------------------------------------------------------------------*/
101
102/*----------------------------------------------------------------------------
103; LOCAL STORE/BUFFER/POINTER DEFINITIONS
104; Variable declaration - defined here and used outside this module
105----------------------------------------------------------------------------*/
106
107/* Look-up table for transformations */
108
109/* table of cos(x) in Q15 */
110
111const int16 table[129] =
112{
113    32767,
114    32758,  32729,  32679,  32610,  32522,  32413,  32286,  32138,
115    31972,  31786,  31581,  31357,  31114,  30853,  30572,  30274,
116    29957,  29622,  29269,  28899,  28511,  28106,  27684,  27246,
117    26791,  26320,  25833,  25330,  24812,  24279,  23732,  23170,
118    22595,  22006,  21403,  20788,  20160,  19520,  18868,  18205,
119    17531,  16846,  16151,  15447,  14733,  14010,  13279,  12540,
120    11793,  11039,  10279,   9512,   8740,   7962,   7180,   6393,
121    5602,   4808,   4011,   3212,   2411,   1608,    804,      0,
122    -804,  -1608,  -2411,  -3212,  -4011,  -4808,  -5602,  -6393,
123    -7180,  -7962,  -8740,  -9512, -10279, -11039, -11793, -12540,
124    -13279, -14010, -14733, -15447, -16151, -16846, -17531, -18205,
125    -18868, -19520, -20160, -20788, -21403, -22006, -22595, -23170,
126    -23732, -24279, -24812, -25330, -25833, -26320, -26791, -27246,
127    -27684, -28106, -28511, -28899, -29269, -29622, -29957, -30274,
128    -30572, -30853, -31114, -31357, -31581, -31786, -31972, -32138,
129    -32286, -32413, -32522, -32610, -32679, -32729, -32758, -32768
130};
131
132
133/*----------------------------------------------------------------------------
134; EXTERNAL FUNCTION REFERENCES
135; Declare functions defined elsewhere and referenced in this module
136----------------------------------------------------------------------------*/
137
138/*----------------------------------------------------------------------------
139; EXTERNAL GLOBAL STORE/BUFFER/POINTER REFERENCES
140; Declare variables used in this module but defined elsewhere
141----------------------------------------------------------------------------*/
142
143/*----------------------------------------------------------------------------
144; FUNCTION CODE
145----------------------------------------------------------------------------*/
146
147
148void Isf_isp(
149    int16 isf[],     /* (i) Q15 : isf[m] normalized (range: 0.0<=val<=0.5) */
150    int16 isp[],     /* (o) Q15 : isp[m] (range: -1<=val<1)                */
151    int16 m          /* (i)     : LPC order                                */
152)
153{
154    int16 i, ind, offset;
155    int32 L_tmp;
156
157    for (i = 0; i < m - 1; i++)
158    {
159        isp[i] = isf[i];
160    }
161    isp[m - 1] = shl_int16(isf[m - 1], 1);
162
163    for (i = 0; i < m; i++)
164    {
165        ind = isp[i] >> 7;            /* ind    = b7-b15 of isf[i] */
166        offset = (isp[i] & 0x007f);       /* offset = b0-b6  of isf[i] */
167
168        /* isp[i] = table[ind]+ ((table[ind+1]-table[ind])*offset) / 128 */
169
170        L_tmp = mul_16by16_to_int32(table[ind + 1] - table[ind], offset);
171        isp[i] = add_int16(table[ind], (int16)(L_tmp >> 8));
172    }
173
174    return;
175}
176