d3_14pf.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 26.073
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 Pathname: ./audio/gsm-amr/c/src/d3_14pf.c
35 Functions: decode_3i40_14bits
36
37     Date: 01/28/2002
38
39------------------------------------------------------------------------------
40 REVISION HISTORY
41
42 Description: Modified to place file in the correct template format. Eliminated
43 use of special functions to perform simple mathematical operations.
44
45 Description: Per review comments...
46 (1) Removed include of "count.h" and "basic_op.h"
47 (2) Updated the pathname to indicate the correct file.  (Line 39)
48
49 Description:  Replaced "int" and/or "char" with OSCL defined types.
50
51 Description:
52
53------------------------------------------------------------------------------
54 MODULE DESCRIPTION
55
56
57 FUNCTION:  decode_3i40_14bits (decod_ACELP())
58
59 PURPOSE:   Algebraic codebook decoder. For details about the encoding see
60            c3_14pf.c
61*/
62
63/*----------------------------------------------------------------------------
64; INCLUDES
65----------------------------------------------------------------------------*/
66#include "typedef.h"
67#include "cnst.h"
68#include "d3_14pf.h"
69
70/*----------------------------------------------------------------------------
71; MACROS
72; Define module specific macros here
73----------------------------------------------------------------------------*/
74
75/*----------------------------------------------------------------------------
76; DEFINES
77; Include all pre-processor statements here. Include conditional
78; compile variables also.
79----------------------------------------------------------------------------*/
80#define NB_PULSE 3           /* number of pulses  */
81
82
83/*----------------------------------------------------------------------------
84; LOCAL FUNCTION DEFINITIONS
85; Function Prototype declaration
86----------------------------------------------------------------------------*/
87
88/*----------------------------------------------------------------------------
89; LOCAL VARIABLE DEFINITIONS
90; Variable declaration - defined here and used outside this module
91----------------------------------------------------------------------------*/
92
93/*
94------------------------------------------------------------------------------
95 FUNCTION NAME: decode_3i40_14bits
96------------------------------------------------------------------------------
97 INPUT AND OUTPUT DEFINITIONS
98
99 Inputs:
100    sign  -- Word16 -- signs of 3 pulses.
101    index -- Word16 -- Positions of the 3 pulses.
102
103 Outputs:
104    cod[] -- array of type Word16 -- algebraic (fixed) codebook excitation
105
106 Returns:
107    None
108
109 Global Variables Used:
110    None
111
112 Local Variables Needed:
113    None
114
115------------------------------------------------------------------------------
116 FUNCTION DESCRIPTION
117
118
119------------------------------------------------------------------------------
120 REQUIREMENTS
121
122 None
123
124------------------------------------------------------------------------------
125 REFERENCES
126
127 d2_9pf.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
128
129------------------------------------------------------------------------------
130 PSEUDO-CODE
131
132
133------------------------------------------------------------------------------
134 RESOURCES USED [optional]
135
136 When the code is written for a specific target processor the
137 the resources used should be documented below.
138
139 HEAP MEMORY USED: x bytes
140
141 STACK MEMORY USED: x bytes
142
143 CLOCK CYCLES: (cycle count equation for this function) + (variable
144                used to represent cycle count for each subroutine
145                called)
146     where: (cycle count variable) = cycle count for [subroutine
147                                     name]
148
149------------------------------------------------------------------------------
150 CAUTION [optional]
151 [State any special notes, constraints or cautions for users of this function]
152
153------------------------------------------------------------------------------
154*/
155
156void decode_3i40_14bits(
157    Word16 sign,   /* i : signs of 3 pulses.                       */
158    Word16 index,  /* i : Positions of the 3 pulses.               */
159    Word16 cod[]   /* o : algebraic (fixed) codebook excitation    */
160)
161{
162    Word16 i;
163    Word16 j;
164
165    Word16 pos[NB_PULSE];
166
167    /* Decode the positions */
168
169    i = index & 0x7;
170
171    pos[0] = i * 5;
172
173
174
175
176
177    index >>= 3;
178
179    j = index & 0x1;
180
181    index >>= 1;
182
183    i = index & 0x7;
184
185    pos[1] = i * 5 + j * 2 + 1;
186
187
188
189
190
191    index >>= 3;
192
193    j = index & 0x1;
194
195    index >>= 1;
196
197    i = index & 0x7;
198
199    pos[2] = i * 5 + j * 2 + 2;
200
201
202    /* decode the signs  and build the codeword */
203
204    for (i = 0; i < L_SUBFR; i++)
205    {
206        cod[i] = 0;
207    }
208
209    for (j = 0; j < NB_PULSE; j++)
210    {
211        i = sign & 1;
212
213        /* This line is equivalent to...
214         *
215         *
216         *  if (i == 1)
217         *  {
218         *      cod[pos[j]] = 8191;
219         *  }
220         *  if (i == 0)
221         *  {
222         *      cod[pos[j]] = -8192;
223         *  }
224         */
225
226        cod[pos[j]] = i * 16383 - 8192;
227
228        sign >>= 1;
229
230    }
231
232    return;
233}
234