|
5
|
1 /*
|
|
|
2 * SpanDSP - a series of DSP components for telephony
|
|
|
3 *
|
|
|
4 * noise_tests.c
|
|
|
5 *
|
|
|
6 * Written by Steve Underwood <steveu@coppice.org>
|
|
|
7 *
|
|
|
8 * Copyright (C) 2005 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: noise_tests.c,v 1.9 2006/11/19 14:07:27 steveu Exp $
|
|
|
26 */
|
|
|
27
|
|
|
28 /*! \page noise_tests_page Noise generator tests
|
|
|
29 \section noise_tests_page_sec_1 What does it do?
|
|
|
30 */
|
|
|
31
|
|
|
32 #ifdef HAVE_CONFIG_H
|
|
|
33 #include "config.h"
|
|
|
34 #endif
|
|
|
35
|
|
|
36 #include <stdio.h>
|
|
|
37 #include <inttypes.h>
|
|
|
38 #include <stdlib.h>
|
|
|
39 #include <string.h>
|
|
|
40 #if defined(HAVE_TGMATH_H)
|
|
|
41 #include <tgmath.h>
|
|
|
42 #endif
|
|
|
43 #if defined(HAVE_MATH_H)
|
|
|
44 #include <math.h>
|
|
|
45 #endif
|
|
|
46 #include <audiofile.h>
|
|
|
47 #include <tiffio.h>
|
|
|
48
|
|
|
49 #include "spandsp.h"
|
|
|
50
|
|
|
51 #if !defined(M_PI)
|
|
|
52 # define M_PI 3.14159265358979323846 /* pi */
|
|
|
53 #endif
|
|
|
54
|
|
|
55 #define OUT_FILE_NAME "noise.wav"
|
|
|
56
|
|
|
57 /* Some simple sanity tests for the noise generation routines */
|
|
|
58
|
|
|
59 int main (int argc, char *argv[])
|
|
|
60 {
|
|
|
61 int i;
|
|
|
62 int j;
|
|
|
63 int level;
|
|
|
64 int clip_high;
|
|
|
65 int clip_low;
|
|
|
66 int total_samples;
|
|
|
67 int seed = 1234567;
|
|
|
68 int outframes;
|
|
|
69 int16_t value;
|
|
|
70 double total;
|
|
|
71 double x;
|
|
|
72 double p;
|
|
|
73 double o;
|
|
|
74 int bins[65536];
|
|
|
75 int16_t amp[1024];
|
|
|
76 noise_state_t noise_source;
|
|
|
77 AFfilehandle outhandle;
|
|
|
78 AFfilesetup filesetup;
|
|
|
79
|
|
|
80 if ((filesetup = afNewFileSetup()) == AF_NULL_FILESETUP)
|
|
|
81 {
|
|
|
82 fprintf(stderr, " Failed to create file setup\n");
|
|
|
83 exit(2);
|
|
|
84 }
|
|
|
85 afInitSampleFormat(filesetup, AF_DEFAULT_TRACK, AF_SAMPFMT_TWOSCOMP, 16);
|
|
|
86 afInitRate(filesetup, AF_DEFAULT_TRACK, (float) SAMPLE_RATE);
|
|
|
87 afInitFileFormat(filesetup, AF_FILE_WAVE);
|
|
|
88 afInitChannels(filesetup, AF_DEFAULT_TRACK, 1);
|
|
|
89 if ((outhandle = afOpenFile(OUT_FILE_NAME, "w", filesetup)) == AF_NULL_FILEHANDLE)
|
|
|
90 {
|
|
|
91 fprintf(stderr, " Cannot create wave file '%s'\n", OUT_FILE_NAME);
|
|
|
92 exit(2);
|
|
|
93 }
|
|
|
94
|
|
|
95 /* Generate AWGN at several RMS levels between -50dBOv and 0dBOv. Noise is
|
|
|
96 generated for a large number of samples (1,000,000), and the RMS value
|
|
|
97 of the noise is calculated along the way. If the resulting level is
|
|
|
98 close to the requested RMS level, at least the scaling of the noise
|
|
|
99 should be Ok. At high levels some clipping may distort the result a
|
|
|
100 little. */
|
|
|
101 printf("Testing with quality 7 AWGN\n");
|
|
|
102 for (level = -50; level <= 0; level += 5)
|
|
|
103 {
|
|
|
104 clip_high = 0;
|
|
|
105 clip_low = 0;
|
|
|
106 total = 0.0;
|
|
|
107 noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, 7);
|
|
|
108 total_samples = 1000000;
|
|
|
109 for (i = 0; i < total_samples; i++)
|
|
|
110 {
|
|
|
111 value = noise(&noise_source);
|
|
|
112 if (value == 32767)
|
|
|
113 clip_high++;
|
|
|
114 else if (value == -32768)
|
|
|
115 clip_low++;
|
|
|
116 total += ((double) value)*((double) value);
|
|
|
117 }
|
|
|
118 printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
|
|
|
119 log10(sqrt(total/total_samples)/32768.0)*20.0,
|
|
|
120 level,
|
|
|
121 100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
|
|
|
122 clip_low,
|
|
|
123 clip_high);
|
|
|
124 if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
|
|
|
125 {
|
|
|
126 printf("Test failed\n");
|
|
|
127 exit(2);
|
|
|
128 }
|
|
|
129 }
|
|
|
130
|
|
|
131 printf("Testing with quality 20 AWGN\n");
|
|
|
132 for (level = -50; level <= 0; level += 5)
|
|
|
133 {
|
|
|
134 clip_high = 0;
|
|
|
135 clip_low = 0;
|
|
|
136 total = 0.0;
|
|
|
137 noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, 20);
|
|
|
138 total_samples = 1000000;
|
|
|
139 for (i = 0; i < total_samples; i++)
|
|
|
140 {
|
|
|
141 value = noise(&noise_source);
|
|
|
142 if (value == 32767)
|
|
|
143 clip_high++;
|
|
|
144 else if (value == -32768)
|
|
|
145 clip_low++;
|
|
|
146 total += ((double) value)*((double) value);
|
|
|
147 }
|
|
|
148 printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
|
|
|
149 log10(sqrt(total/total_samples)/32768.0)*20.0,
|
|
|
150 level,
|
|
|
151 100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
|
|
|
152 clip_low,
|
|
|
153 clip_high);
|
|
|
154 if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
|
|
|
155 {
|
|
|
156 printf("Test failed\n");
|
|
|
157 exit(2);
|
|
|
158 }
|
|
|
159 }
|
|
|
160
|
|
|
161 /* Now look at the statistical spread of the results, by collecting data in
|
|
|
162 bins from a large number of samples. Use a fairly high noise level, but
|
|
|
163 low enough to avoid significant clipping. Use the Gaussian model to
|
|
|
164 predict the real probability, and present the results for graphing. */
|
|
|
165 memset(bins, 0, sizeof(bins));
|
|
|
166 clip_high = 0;
|
|
|
167 clip_low = 0;
|
|
|
168 level = -15;
|
|
|
169 noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, 7);
|
|
|
170 total_samples = 10000000;
|
|
|
171 for (i = 0; i < total_samples; i++)
|
|
|
172 {
|
|
|
173 value = noise(&noise_source);
|
|
|
174 if (value == 32767)
|
|
|
175 clip_high++;
|
|
|
176 else if (value == -32768)
|
|
|
177 clip_low++;
|
|
|
178 bins[value + 32768]++;
|
|
|
179 }
|
|
|
180 /* Find the RMS power level to expect */
|
|
|
181 o = pow(10.0, level/20.0)*(32768.0*0.70711);
|
|
|
182 for (i = 0; i < 65536 - 10; i++)
|
|
|
183 {
|
|
|
184 x = i - 32768;
|
|
|
185 /* Find the real probability for this bin */
|
|
|
186 p = (1.0/(o*sqrt(2.0*M_PI)))*exp(-(x*x)/(2.0*o*o));
|
|
|
187 /* Now do a little smoothing on the real data to get a reasonably
|
|
|
188 steady answer */
|
|
|
189 x = 0;
|
|
|
190 for (j = 0; j < 10; j++)
|
|
|
191 x += bins[i + j];
|
|
|
192 x /= 10.0;
|
|
|
193 x /= total_samples;
|
|
|
194 /* Now send it out for graphing. */
|
|
|
195 if (p > 0.0000001)
|
|
|
196 printf("%6d %.7f %.7f\n", i - 32768, x, p);
|
|
|
197 }
|
|
|
198
|
|
|
199 printf("Generating AWGN at -15dBOv to file\n");
|
|
|
200 for (j = 0; j < 50; j++)
|
|
|
201 {
|
|
|
202 for (i = 0; i < 1024; i++)
|
|
|
203 amp[i] = noise(&noise_source);
|
|
|
204 outframes = afWriteFrames(outhandle,
|
|
|
205 AF_DEFAULT_TRACK,
|
|
|
206 amp,
|
|
|
207 1024);
|
|
|
208 if (outframes != 1024)
|
|
|
209 {
|
|
|
210 fprintf(stderr, " Error writing wave file\n");
|
|
|
211 exit(2);
|
|
|
212 }
|
|
|
213 }
|
|
|
214
|
|
|
215 /* Generate AWGN at several RMS levels between -50dBm and 0dBm. Noise is
|
|
|
216 generated for a large number of samples (1,000,000), and the RMS value
|
|
|
217 of the noise is calculated along the way. If the resulting level is
|
|
|
218 close to the requested RMS level, at least the scaling of the noise
|
|
|
219 should be Ok. At high levels some clipping may distort the result a
|
|
|
220 little. */
|
|
|
221 printf("Testing with quality 7 Hoth noise.\n");
|
|
|
222 for (level = -50; level <= 0; level += 5)
|
|
|
223 {
|
|
|
224 clip_high = 0;
|
|
|
225 clip_low = 0;
|
|
|
226 total = 0.0;
|
|
|
227 noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, 7);
|
|
|
228 total_samples = 1000000;
|
|
|
229 for (i = 0; i < total_samples; i++)
|
|
|
230 {
|
|
|
231 value = noise(&noise_source);
|
|
|
232 if (value == 32767)
|
|
|
233 clip_high++;
|
|
|
234 else if (value == -32768)
|
|
|
235 clip_low++;
|
|
|
236 total += ((double) value)*((double) value);
|
|
|
237 }
|
|
|
238 printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
|
|
|
239 log10(sqrt(total/total_samples)/32768.0)*20.0,
|
|
|
240 level,
|
|
|
241 100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
|
|
|
242 clip_low,
|
|
|
243 clip_high);
|
|
|
244 if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
|
|
|
245 {
|
|
|
246 printf("Test failed\n");
|
|
|
247 exit(2);
|
|
|
248 }
|
|
|
249 }
|
|
|
250
|
|
|
251 printf("Generating Hoth noise at -15dBOv to file\n");
|
|
|
252 level = -15;
|
|
|
253 noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, 7);
|
|
|
254 for (j = 0; j < 50; j++)
|
|
|
255 {
|
|
|
256 for (i = 0; i < 1024; i++)
|
|
|
257 amp[i] = noise(&noise_source);
|
|
|
258 outframes = afWriteFrames(outhandle,
|
|
|
259 AF_DEFAULT_TRACK,
|
|
|
260 amp,
|
|
|
261 1024);
|
|
|
262 if (outframes != 1024)
|
|
|
263 {
|
|
|
264 fprintf(stderr, " Error writing wave file\n");
|
|
|
265 exit(2);
|
|
|
266 }
|
|
|
267 }
|
|
|
268
|
|
|
269 if (afCloseFile(outhandle))
|
|
|
270 {
|
|
|
271 fprintf(stderr, " Cannot close wave file '%s'\n", OUT_FILE_NAME);
|
|
|
272 exit(2);
|
|
|
273 }
|
|
|
274 afFreeFileSetup(filesetup);
|
|
|
275
|
|
|
276 printf("Tests passed.\n");
|
|
|
277 return 0;
|
|
|
278 }
|
|
|
279 /*- End of function --------------------------------------------------------*/
|
|
|
280 /*- End of file ------------------------------------------------------------*/
|
