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/enc_lag3.c
35 Functions:
36
37 Date: 01/28/2002
38
39 ------------------------------------------------------------------------------
40 REVISION HISTORY
41
42 Description: Replaced "int" and/or "char" with OSCL defined types.
43
44 Description:
45
46 ------------------------------------------------------------------------------
47 */
48
49 /*----------------------------------------------------------------------------
50 ; INCLUDES
51 ----------------------------------------------------------------------------*/
52 #include "enc_lag3.h"
53 #include "typedef.h"
54 #include "basic_op.h"
55 #include "cnst.h"
56
57 /*----------------------------------------------------------------------------
58 ; MACROS
59 ; Define module specific macros here
60 ----------------------------------------------------------------------------*/
61
62 /*----------------------------------------------------------------------------
63 ; DEFINES
64 ; Include all pre-processor statements here. Include conditional
65 ; compile variables also.
66 ----------------------------------------------------------------------------*/
67
68
69 /*----------------------------------------------------------------------------
70 ; LOCAL FUNCTION DEFINITIONS
71 ; Function Prototype declaration
72 ----------------------------------------------------------------------------*/
73
74
75 /*----------------------------------------------------------------------------
76 ; LOCAL VARIABLE DEFINITIONS
77 ; Variable declaration - defined here and used outside this module
78 ----------------------------------------------------------------------------*/
79
80 /*
81 ------------------------------------------------------------------------------
82 FUNCTION NAME: enc_lag3
83 ------------------------------------------------------------------------------
84 INPUT AND OUTPUT DEFINITIONS
85
86 Inputs:
87 T0 = Pitch delay of type Word16
88 T0_frac = Fractional pitch delay of type Word16
89 T0_prev = Integer pitch delay of last subframe of type Word16
90 T0_min = minimum of search range of type Word16
91 T0_max = maximum of search range of type Word16
92 delta_flag = Flag for 1st (or 3rd) subframe of type Word16
93 flag4 = Flag for encoding with 4 bits of type Word16
94 pOverflow = pointer indicating overflow of type Flag
95
96 Outputs:
97 pOverflow = 1 if there is an overflow else it is zero.
98
99 Returns:
100 None
101
102 Global Variables Used:
103 None
104
105 Local Variables Needed:
106 None
107
108 ------------------------------------------------------------------------------
109 FUNCTION DESCRIPTION
110
111 This function implements the encoding of fractional pitch lag with
112 1/3 resolution.
113
114 * FUNCTION: Enc_lag3
115 *
116 * PURPOSE: Encoding of fractional pitch lag with 1/3 resolution.
117 *
118 * DESCRIPTION:
119 * First and third subframes:
120 * --------------------------
121 * The pitch range is divided as follows:
122 * 19 1/3 to 84 2/3 resolution 1/3
123 * 85 to 143 resolution 1
124 *
125 * The period is encoded with 8 bits.
126 * For the range with fractions:
127 * index = (T-19)*3 + frac - 1;
128 * where T=[19..85] and frac=[-1,0,1]
129 * and for the integer only range
130 * index = (T - 85) + 197; where T=[86..143]
131 *
132 * Second and fourth subframes:
133 * ----------------------------
134 * For the 2nd and 4th subframes a resolution of 1/3 is always used,
135 * and the search range is relative to the lag in previous subframe.
136 * If t0 is the lag in the previous subframe then
137 * t_min=t0-5 and t_max=t0+4 and the range is given by
138 * t_min - 2/3 to t_max + 2/3
139 *
140 * The period in the 2nd (and 4th) subframe is encoded with 5 bits:
141 * index = (T-(t_min-1))*3 + frac - 1;
142 * where T=[t_min-1..t_max+1]
143
144 ------------------------------------------------------------------------------
145 REQUIREMENTS
146
147 None
148
149 ------------------------------------------------------------------------------
150 REFERENCES
151
152 enc_lag3.c, UMTS GSM AMR speech codec, R99 - Version 3.2.0, March 2, 2001
153
154 ------------------------------------------------------------------------------
155 PSEUDO-CODE
156
157 Word16 index, i, tmp_ind, uplag;
158 Word16 tmp_lag;
159
160 if (delta_flag == 0)
161 { // if 1st or 3rd subframe
162
163 // encode pitch delay (with fraction)
164
165 if (sub (T0, 85) <= 0)
166 {
167 // index = T0*3 - 58 + T0_frac
168 i = add (add (T0, T0), T0);
169 index = add (sub (i, 58), T0_frac);
170 }
171 else
172 {
173 index = add (T0, 112);
174 }
175 }
176 else
177 { // if second or fourth subframe
178 if (flag4 == 0) {
179
180 // 'normal' encoding: either with 5 or 6 bit resolution
181
182 // index = 3*(T0 - T0_min) + 2 + T0_frac
183 i = sub (T0, T0_min);
184 i = add (add (i, i), i);
185 index = add (add (i, 2), T0_frac);
186 }
187 else {
188
189 // encoding with 4 bit resolution
190
191 tmp_lag = T0_prev;
192
193 if ( sub( sub(tmp_lag, T0_min), 5) > 0)
194 tmp_lag = add (T0_min, 5);
195 if ( sub( sub(T0_max, tmp_lag), 4) > 0)
196 tmp_lag = sub (T0_max, 4);
197
198 uplag = add (add (add (T0, T0), T0), T0_frac);
199
200 i = sub (tmp_lag, 2);
201 tmp_ind = add (add (i, i), i);
202
203 if (sub (tmp_ind, uplag) >= 0) {
204 index = add (sub (T0, tmp_lag), 5);
205 }
206 else {
207
208 i = add (tmp_lag, 1);
209 i = add (add (i, i), i);
210
211 if (sub (i, uplag) > 0) {
212
213 index = add ( sub (uplag, tmp_ind), 3);
214 }
215 else {
216
217 index = add (sub (T0, tmp_lag), 11);
218 }
219 }
220
221 } // end if (encoding with 4 bit resolution)
222 } // end if (second of fourth subframe)
223
224 return index;
225 }
226
227 ------------------------------------------------------------------------------
228 RESOURCES USED [optional]
229
230 When the code is written for a specific target processor the
231 the resources used should be documented below.
232
233 HEAP MEMORY USED: x bytes
234
235 STACK MEMORY USED: x bytes
236
237 CLOCK CYCLES: (cycle count equation for this function) + (variable
238 used to represent cycle count for each subroutine
239 called)
240 where: (cycle count variable) = cycle count for [subroutine
241 name]
242
243 ------------------------------------------------------------------------------
244 CAUTION [optional]
245 [State any special notes, constraints or cautions for users of this function]
246
247 ------------------------------------------------------------------------------
248 */
249
250
Enc_lag3(Word16 T0,Word16 T0_frac,Word16 T0_prev,Word16 T0_min,Word16 T0_max,Word16 delta_flag,Word16 flag4,Flag * pOverflow)251 Word16 Enc_lag3( /* o : Return index of encoding */
252 Word16 T0, /* i : Pitch delay */
253 Word16 T0_frac, /* i : Fractional pitch delay */
254 Word16 T0_prev, /* i : Integer pitch delay of last subframe */
255 Word16 T0_min, /* i : minimum of search range */
256 Word16 T0_max, /* i : maximum of search range */
257 Word16 delta_flag, /* i : Flag for 1st (or 3rd) subframe */
258 Word16 flag4, /* i : Flag for encoding with 4 bits */
259 Flag *pOverflow
260 )
261 {
262 Word16 index, i, tmp_ind, uplag;
263 Word16 tmp_lag;
264 Word16 temp1;
265 Word16 temp2;
266
267
268
269 if (delta_flag == 0)
270 { /* if 1st or 3rd subframe */
271
272 /* encode pitch delay (with fraction) */
273 temp1 = sub(T0, 85, pOverflow);
274 if (temp1 <= 0)
275 {
276 /* index = T0*3 - 58 + T0_frac */
277 temp2 = add(T0, T0, pOverflow);
278 i = add(temp2, T0, pOverflow);
279 temp2 = sub(i, 58, pOverflow);
280 index = add(temp2, T0_frac, pOverflow);
281 }
282 else
283 {
284 index = add(T0, 112, pOverflow);
285 }
286 }
287 else
288 { /* if second or fourth subframe */
289 if (flag4 == 0)
290 {
291
292 /* 'normal' encoding: either with 5 or 6 bit resolution */
293
294 /* index = 3*(T0 - T0_min) + 2 + T0_frac */
295 i = sub(T0, T0_min, pOverflow);
296 temp2 = add(i, i, pOverflow);
297 i = add(temp2, i, pOverflow);
298 temp2 = add(i, 2, pOverflow);
299 index = add(temp2, T0_frac, pOverflow);
300 }
301 else
302 {
303
304 /* encoding with 4 bit resolution */
305
306 tmp_lag = T0_prev;
307 temp1 = sub(tmp_lag, T0_min, pOverflow);
308 temp2 = sub(temp1, 5, pOverflow);
309 if (temp2 > 0)
310 tmp_lag = add(T0_min, 5, pOverflow);
311 temp1 = sub(T0_max, tmp_lag, pOverflow);
312 temp2 = sub(temp1, 4, pOverflow);
313 if (temp2 > 0)
314 tmp_lag = sub(T0_max, 4, pOverflow);
315
316 temp1 = add(T0, T0, pOverflow);
317 temp2 = add(temp1, T0, pOverflow);
318 uplag = add(temp2, T0_frac, pOverflow);
319
320 i = sub(tmp_lag, 2, pOverflow);
321 temp1 = add(i, i, pOverflow);
322 tmp_ind = add(temp1, i, pOverflow);
323
324 temp1 = sub(tmp_ind, uplag, pOverflow);
325 if (temp1 >= 0)
326 {
327 temp1 = sub(T0, tmp_lag, pOverflow);
328 index = add(temp1, 5, pOverflow);
329 }
330 else
331 {
332
333 i = add(tmp_lag, 1, pOverflow);
334 temp1 = add(i, i, pOverflow);
335 i = add(temp1, i, pOverflow);
336
337 if (sub(i, uplag, pOverflow) > 0)
338 {
339 temp1 = sub(uplag, tmp_ind, pOverflow);
340 index = add(temp1, 3, pOverflow);
341 }
342 else
343 {
344 temp1 = sub(T0, tmp_lag, pOverflow);
345 index = add(temp1, 11, pOverflow);
346 }
347 }
348
349 } /* end if (encoding with 4 bit resolution) */
350 } /* end if (second of fourth subframe) */
351
352 return index;
353 }
354
355
356
357