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comparison spandsp-0.0.3/spandsp-0.0.3/src/time_scale.c @ 5:f762bf195c4b

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import spandsp-0.0.3
author Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date Fri, 25 Jun 2010 16:00:21 +0200
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4:26cd8f1ef0b1 5:f762bf195c4b
1 /*
2 * SpanDSP - a series of DSP components for telephony
3 *
4 * time_scale.c - Time scaling for linear speech data
5 *
6 * Written by Steve Underwood <steveu@coppice.org>
7 *
8 * Copyright (C) 2004 Steve Underwood
9 *
10 * All rights reserved.
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2, as
14 * published by the Free Software Foundation.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
24 *
25 * $Id: time_scale.c,v 1.15 2006/11/19 14:07:25 steveu Exp $
26 */
27
28 /*! \file */
29
30 #ifdef HAVE_CONFIG_H
31 #include <config.h>
32 #endif
33
34 #include <stdlib.h>
35 #include <stdio.h>
36 #include <inttypes.h>
37 #include <string.h>
38 #include <fcntl.h>
39 #include <time.h>
40 #include <limits.h>
41 #if defined(HAVE_TGMATH_H)
42 #include <tgmath.h>
43 #endif
44 #if defined(HAVE_MATH_H)
45 #include <math.h>
46 #endif
47
48 #include "spandsp/telephony.h"
49 #include "spandsp/time_scale.h"
50
51 /*
52 Time scaling for speech, based on the Pointer Interval Controlled
53 OverLap and Add (PICOLA) method, developed by Morita Naotaka.
54 */
55
56 static __inline__ int amdf_pitch(int min_pitch, int max_pitch, int16_t amp[], int len)
57 {
58 int i;
59 int j;
60 int acc;
61 int min_acc;
62 int pitch;
63
64 pitch = min_pitch;
65 min_acc = INT_MAX;
66 for (i = max_pitch; i <= min_pitch; i++)
67 {
68 acc = 0;
69 for (j = 0; j < len; j++)
70 acc += abs(amp[i + j] - amp[j]);
71 if (acc < min_acc)
72 {
73 min_acc = acc;
74 pitch = i;
75 }
76 }
77 return pitch;
78 }
79 /*- End of function --------------------------------------------------------*/
80
81 static __inline__ void overlap_add(int16_t amp1[], int16_t amp2[], int len)
82 {
83 int i;
84 double weight;
85 double step;
86
87 step = 1.0/len;
88 weight = 0.0;
89 for (i = 0; i < len; i++)
90 {
91 /* TODO: saturate */
92 amp2[i] = (int16_t) ((double) amp1[i]*(1.0 - weight) + (double) amp2[i]*weight);
93 weight += step;
94 }
95 }
96 /*- End of function --------------------------------------------------------*/
97
98 int time_scale_rate(time_scale_t *s, float rate)
99 {
100 if (rate <= 0.0)
101 return -1;
102 /*endif*/
103 if (rate >= 0.99 && rate <= 1.01)
104 {
105 /* Treat rate close to normal speed as exactly normal speed, and
106 avoid divide by zero, and other numerical problems. */
107 rate = 1.0;
108 }
109 else if (rate < 1.0)
110 {
111 s->rcomp = rate/(1.0 - rate);
112 }
113 else
114 {
115 s->rcomp = 1.0/(rate - 1.0);
116 }
117 /*endif*/
118 s->rate = rate;
119 return 0;
120 }
121 /*- End of function --------------------------------------------------------*/
122
123 int time_scale_init(time_scale_t *s, float rate)
124 {
125 if (time_scale_rate(s, rate))
126 return -1;
127 /*endif*/
128 s->rate_nudge = 0.0;
129 s->fill = 0;
130 s->lcp = 0;
131 return 0;
132 }
133 /*- End of function --------------------------------------------------------*/
134
135 int time_scale(time_scale_t *s, int16_t out[], int16_t in[], int len)
136 {
137 double lcpf;
138 int pitch;
139 int out_len;
140 int in_len;
141 int k;
142
143 out_len = 0;
144 in_len = 0;
145
146 /* Top up the buffer */
147 if (s->fill + len < TIME_SCALE_BUF_LEN)
148 {
149 /* Cannot continue without more samples */
150 memcpy(s->buf + s->fill, in, sizeof(int16_t)*len);
151 s->fill += len;
152 return out_len;
153 }
154 k = (TIME_SCALE_BUF_LEN - s->fill);
155 memcpy(s->buf + s->fill, in, sizeof(int16_t)*k);
156 in_len += k;
157 s->fill = TIME_SCALE_BUF_LEN;
158 while (s->fill == TIME_SCALE_BUF_LEN)
159 {
160 while (s->lcp >= TIME_SCALE_BUF_LEN)
161 {
162 memcpy(out + out_len, s->buf, sizeof(int16_t)*TIME_SCALE_BUF_LEN);
163 out_len += TIME_SCALE_BUF_LEN;
164 if (len - in_len < TIME_SCALE_BUF_LEN)
165 {
166 /* Cannot continue without more samples */
167 memcpy(s->buf, in + in_len, sizeof(int16_t)*(len - in_len));
168 s->fill = len - in_len;
169 s->lcp -= TIME_SCALE_BUF_LEN;
170 return out_len;
171 }
172 memcpy(s->buf, in + in_len, sizeof(int16_t)*TIME_SCALE_BUF_LEN);
173 in_len += TIME_SCALE_BUF_LEN;
174 s->lcp -= TIME_SCALE_BUF_LEN;
175 }
176 if (s->lcp > 0)
177 {
178 memcpy(out + out_len, s->buf, sizeof(int16_t)*s->lcp);
179 out_len += s->lcp;
180 memcpy(s->buf, s->buf + s->lcp, sizeof(int16_t)*(TIME_SCALE_BUF_LEN - s->lcp));
181 if (len - in_len < s->lcp)
182 {
183 /* Cannot continue without more samples */
184 memcpy(s->buf + (TIME_SCALE_BUF_LEN - s->lcp), in + in_len, sizeof(int16_t)*(len - in_len));
185 s->fill = TIME_SCALE_BUF_LEN - s->lcp + len - in_len;
186 s->lcp = 0;
187 return out_len;
188 }
189 memcpy(s->buf + (TIME_SCALE_BUF_LEN - s->lcp), in + in_len, sizeof(int16_t)*s->lcp);
190 in_len += s->lcp;
191 s->lcp = 0;
192 }
193 if (s->rate == 1.0)
194 {
195 s->lcp = 0x7FFFFFFF;
196 }
197 else
198 {
199 pitch = amdf_pitch(SAMPLE_RATE/TIME_SCALE_MIN_PITCH, SAMPLE_RATE/TIME_SCALE_MAX_PITCH, s->buf, SAMPLE_RATE/TIME_SCALE_MIN_PITCH);
200 lcpf = (double) pitch*s->rcomp;
201 /* Nudge around to compensate for fractional samples */
202 s->lcp = (int) lcpf;
203 /* Note that s->lcp and lcpf are not the same, as lcpf has a fractional part, and s->lcp doesn't */
204 s->rate_nudge += s->lcp - lcpf;
205 if (s->rate_nudge >= 0.5)
206 {
207 s->lcp--;
208 s->rate_nudge -= 1.0;
209 }
210 else if (s->rate_nudge <= -0.5)
211 {
212 s->lcp++;
213 s->rate_nudge += 1.0;
214 }
215 if (s->rate < 1.0)
216 {
217 /* Speed up - drop a chunk of data */
218 overlap_add(s->buf, s->buf + pitch, pitch);
219 memcpy(&s->buf[pitch], &s->buf[2*pitch], sizeof(int16_t)*(TIME_SCALE_BUF_LEN - 2*pitch));
220 if (len - in_len < pitch)
221 {
222 /* Cannot continue without more samples */
223 memcpy(s->buf + TIME_SCALE_BUF_LEN - pitch, in + in_len, sizeof(int16_t)*(len - in_len));
224 s->fill += (len - in_len - pitch);
225 return out_len;
226 }
227 memcpy(s->buf + TIME_SCALE_BUF_LEN - pitch, in + in_len, sizeof(int16_t)*pitch);
228 in_len += pitch;
229 }
230 else
231 {
232 /* Slow down - insert a chunk of data */
233 memcpy(out + out_len, s->buf, sizeof(int16_t)*pitch);
234 out_len += pitch;
235 overlap_add(s->buf + pitch, s->buf, pitch);
236 }
237 }
238 }
239 return out_len;
240 }
241 /*- End of function --------------------------------------------------------*/
242 /*- End of file ------------------------------------------------------------*/

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