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 26.073
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)
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 Pathname: ./audio/gsm-amr/c/src/preemph.c
35 Functions:
36
37 Date: 02/04/2002
38
39 ------------------------------------------------------------------------------
40 REVISION HISTORY
41
42 Description: Removed the functions preemphasis_init and preemphasis_exit.
43 The preemphasis related structure is no longer dynamically allocated.
44 Placed file in the appropriate PV Software Template format.
45
46 Description: Changed to accept the pOverflow flag for EPOC compatibility.
47
48 Description: Replaced OSCL mem type functions and eliminated include
49 files that now are chosen by OSCL definitions
50
51 Description: Replaced "int" and/or "char" with OSCL defined types.
52
53 Description:
54
55 ------------------------------------------------------------------------------
56 MODULE DESCRIPTION
57
58 Purpose : Preemphasis filtering
59 Description : Filtering through 1 - g z^-1
60
61 ------------------------------------------------------------------------------
62 */
63
64 /*----------------------------------------------------------------------------
65 ; INCLUDES
66 ----------------------------------------------------------------------------*/
67 #include "preemph.h"
68 #include "typedef.h"
69 #include "basic_op.h"
70
71 /*----------------------------------------------------------------------------
72 ; MACROS
73 ; Define module specific macros here
74 ----------------------------------------------------------------------------*/
75
76 /*----------------------------------------------------------------------------
77 ; DEFINES
78 ; Include all pre-processor statements here. Include conditional
79 ; compile variables also.
80 ----------------------------------------------------------------------------*/
81
82 /*----------------------------------------------------------------------------
83 ; LOCAL FUNCTION DEFINITIONS
84 ; Function Prototype declaration
85 ----------------------------------------------------------------------------*/
86
87 /*----------------------------------------------------------------------------
88 ; LOCAL VARIABLE DEFINITIONS
89 ; Variable declaration - defined here and used outside this module
90 ----------------------------------------------------------------------------*/
91
92
93 /*
94 ------------------------------------------------------------------------------
95 FUNCTION NAME: preemphasis_reset
96 ------------------------------------------------------------------------------
97 INPUT AND OUTPUT DEFINITIONS
98
99 Inputs:
100 st -- double pointer to preemphasisState
101
102 Outputs:
103 st -- double ponter to preemphasisState
104
105 Returns:
106 -1 if an error occurs
107 0 if OK
108
109 Global Variables Used:
110 None
111
112 Local Variables Needed:
113 None
114
115 ------------------------------------------------------------------------------
116 FUNCTION DESCRIPTION
117
118 Initializes state memory to zero
119 ------------------------------------------------------------------------------
120 REQUIREMENTS
121
122 None
123
124 ------------------------------------------------------------------------------
125 REFERENCES
126
127 preemph.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
preemphasis_reset(preemphasisState * state)156 Word16 preemphasis_reset(preemphasisState *state)
157 {
158 if (state == (preemphasisState *) NULL)
159 {
160 /* fprintf(stderr, "preemphasis_reset: invalid parameter\n"); */
161 return -1;
162 }
163
164 state->mem_pre = 0;
165
166 return 0;
167 }
168
169 /*
170 ------------------------------------------------------------------------------
171 FUNCTION NAME: preemphasis
172 ------------------------------------------------------------------------------
173 INPUT AND OUTPUT DEFINITIONS
174
175 Inputs:
176 st -- Pointer to preemphasisState -- preemphasis filter state
177 signal -- array of type Word16 -- input signal overwritten by the output
178 g -- Word16 -- preemphasis coefficient
179 L -- Word16 -- size of filtering
180
181 Outputs:
182 st -- Pointer to preemphasisState -- preemphasis filter state
183 signal -- array of type Word16 -- input signal overwritten by the output
184 pOverflow -- pointer to type Flag -- overflow indicator
185 Returns:
186 None
187
188 Global Variables Used:
189 None
190
191 Local Variables Needed:
192 None
193
194 ------------------------------------------------------------------------------
195 FUNCTION DESCRIPTION
196
197 Filtering through 1 - g z^-1
198 ------------------------------------------------------------------------------
199 REQUIREMENTS
200
201 None
202
203 ------------------------------------------------------------------------------
204 REFERENCES
205
206 preemph.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
207
208 ------------------------------------------------------------------------------
209 PSEUDO-CODE
210
211
212 ------------------------------------------------------------------------------
213 RESOURCES USED [optional]
214
215 When the code is written for a specific target processor the
216 the resources used should be documented below.
217
218 HEAP MEMORY USED: x bytes
219
220 STACK MEMORY USED: x bytes
221
222 CLOCK CYCLES: (cycle count equation for this function) + (variable
223 used to represent cycle count for each subroutine
224 called)
225 where: (cycle count variable) = cycle count for [subroutine
226 name]
227
228 ------------------------------------------------------------------------------
229 CAUTION [optional]
230 [State any special notes, constraints or cautions for users of this function]
231
232 ------------------------------------------------------------------------------
233 */
234
235
preemphasis(preemphasisState * st,Word16 * signal,Word16 g,Word16 L,Flag * pOverflow)236 void preemphasis(
237 preemphasisState *st, /* (i/o) : preemphasis filter state */
238 Word16 *signal, /* (i/o) : input signal overwritten by the output */
239 Word16 g, /* (i) : preemphasis coefficient */
240 Word16 L, /* (i) : size of filtering */
241 Flag *pOverflow /* (o) : overflow indicator */
242 )
243 {
244 Word16 *p1;
245 Word16 *p2;
246 Word16 temp;
247 Word16 temp2;
248 Word16 i;
249
250 p1 = signal + L - 1;
251 p2 = p1 - 1;
252 temp = *p1;
253
254 for (i = 0; i <= L - 2; i++)
255 {
256 temp2 = mult(g, *(p2--), pOverflow);
257 *p1 = sub(*p1, temp2, pOverflow);
258
259 p1--;
260 }
261
262 temp2 = mult(g, st->mem_pre, pOverflow);
263
264 *p1 = sub(*p1, temp2, pOverflow);
265
266 st->mem_pre = temp;
267
268 return;
269 }
270
271
272
273