File: echos.c

package info (click to toggle)
sox 12.16-6
  • links: PTS
  • area: main
  • in suites: potato
  • size: 1,180 kB
  • ctags: 1,466
  • sloc: ansic: 16,658; sh: 2,071; makefile: 126
file content (265 lines) | stat: -rw-r--r-- 7,481 bytes parent folder | download
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
/*
 * August 24, 1998
 * Copyright (C) 1998 Juergen Mueller And Sundry Contributors
 * This source code is freely redistributable and may be used for
 * any purpose.  This copyright notice must be maintained. 
 * Juergen Mueller And Sundry Contributors are not responsible for 
 * the consequences of using this software.
 */

/*
 * Echos effect for dsp.
 * 
 * Flow diagram scheme for n delays ( 1 <= n <= MAX_ECHOS ):
 *
 *                                                    * gain-in  ___
 * ibuff --+--------------------------------------------------->|   |
 *         |                                          * decay 1 |   |
 *         |               +----------------------------------->|   |
 *         |               |                          * decay 2 | + |
 *         |               |             +--------------------->|   |
 *         |               |             |            * decay n |   |
 *         |    _________  |  _________  |     _________   +--->|___|
 *         |   |         | | |         | |    |         |  |      | 
 *         +-->| delay 1 |-+-| delay 2 |-+...-| delay n |--+      | * gain-out
 *             |_________|   |_________|      |_________|         |
 *                                                                +----->obuff
 *
 * Usage: 
 *   echos gain-in gain-out delay-1 decay-1 [delay-2 decay-2 ... delay-n decay-n]
 *
 * Where:
 *   gain-in, decay-1 ... decay-n :  0.0 ... 1.0      volume
 *   gain-out :  0.0 ...      volume
 *   delay-1 ... delay-n :  > 0.0 msec
 *
 * Note:
 *   when decay is close to 1.0, the samples can begin clipping and the output
 *   can saturate! 
 *
 * Hint:
 *   1 / out-gain > gain-in ( 1 + decay-1 + ... + decay-n )
 *
*/

/*
 * Sound Tools reverb effect file.
 */

#include <stdlib.h> /* Harmless, and prototypes atof() etc. --dgc */
#ifdef HAVE_MALLOC_H
#include <malloc.h>
#endif
#include <math.h>
#include "st.h"

#define DELAY_BUFSIZ ( 50L * MAXRATE )
#define MAX_ECHOS 7	/* 24 bit x ( 1 + MAX_ECHOS ) = */
			/* 24 bit x 8 = 32 bit !!!	*/

/* Private data for SKEL file */
typedef struct echosstuff {
	int	counter[MAX_ECHOS];			
	int	num_delays;
	double	*delay_buf;
	float	in_gain, out_gain;
	float	delay[MAX_ECHOS], decay[MAX_ECHOS];
	long	samples[MAX_ECHOS], pointer[MAX_ECHOS], sumsamples;
} *echos_t;

/* Private data for SKEL file */


/* If we are not carefull with the output volume */
LONG echos_clip24(l)
LONG l;
{
	if (l >= ((LONG)1 << 24))
		return ((LONG)1 << 24) - 1;
	else if (l <= -((LONG)1 << 24))
		return -((LONG)1 << 24) + 1;
	else
		return l;
}



/*
 * Process options
 */
void echos_getopts(effp, n, argv) 
eff_t effp;
int n;
char **argv;
{
	echos_t echos = (echos_t) effp->priv;
	int i;

	echos->num_delays = 0;

	if ((n < 4) || (n % 2))
	    fail("Usage: echos gain-in gain-out delay decay [ delay decay ... ]");

	i = 0;
	sscanf(argv[i++], "%f", &echos->in_gain);
	sscanf(argv[i++], "%f", &echos->out_gain);
	while (i < n) {
		/* Linux bug and it's cleaner. */
		sscanf(argv[i++], "%f", &echos->delay[echos->num_delays]);
		sscanf(argv[i++], "%f", &echos->decay[echos->num_delays]);
		echos->num_delays++;
		if ( echos->num_delays > MAX_ECHOS )
			fail("echos: to many delays, use less than %i delays",
				MAX_ECHOS);
	}
	echos->sumsamples = 0;
}

/*
 * Prepare for processing.
 */
void echos_start(effp)
eff_t effp;
{
	echos_t echos = (echos_t) effp->priv;
	int i;
	float sum_in_volume;
	long j;

	if ( echos->in_gain < 0.0 )
		fail("echos: gain-in must be positive!\n");
	if ( echos->in_gain > 1.0 )
		fail("echos: gain-in must be less than 1.0!\n");
	if ( echos->out_gain < 0.0 )
		fail("echos: gain-in must be positive!\n");
	for ( i = 0; i < echos->num_delays; i++ ) {
		echos->samples[i] = echos->delay[i] * effp->ininfo.rate / 1000.0;
		if ( echos->samples[i] < 1 )
		    fail("echos: delay must be positive!\n");
		if ( echos->samples[i] > DELAY_BUFSIZ )
			fail("echos: delay must be less than %g seconds!\n",
				DELAY_BUFSIZ / (float) effp->ininfo.rate );
		if ( echos->decay[i] < 0.0 )
		    fail("echos: decay must be positive!\n" );
		if ( echos->decay[i] > 1.0 )
		    fail("echos: decay must be less than 1.0!\n" );
		echos->counter[i] = 0;
		echos->pointer[i] = echos->sumsamples;
		echos->sumsamples += echos->samples[i];
	}
	if (! (echos->delay_buf = (double *) malloc(sizeof (double) * echos->sumsamples)))
		fail("echos: Cannot malloc %d bytes!\n", 
			sizeof(long) * echos->sumsamples);
	for ( j = 0; j < echos->samples[i]; ++j )
		echos->delay_buf[j] = 0.0;
	/* Be nice and check the hint with warning, if... */
	sum_in_volume = 1.0;
	for ( i = 0; i < echos->num_delays; i++ ) 
		sum_in_volume += echos->decay[i];
	if ( sum_in_volume * echos->in_gain > 1.0 / echos->out_gain )
		warn("echos: warning >>> gain-out can cause saturation of output <<<");
}

/*
 * Processed signed long samples from ibuf to obuf.
 * Return number of samples processed.
 */

void echos_flow(effp, ibuf, obuf, isamp, osamp)
eff_t effp;
LONG *ibuf, *obuf;
int *isamp, *osamp;
{
	echos_t echos = (echos_t) effp->priv;
	int len, done;
	int j;
	
	double d_in, d_out;
	LONG out;

	len = ((*isamp > *osamp) ? *osamp : *isamp);
	for(done = 0; done < len; done++) {
		/* Store delays as 24-bit signed longs */
		d_in = (double) *ibuf++ / 256;
		/* Compute output first */
		d_out = d_in * echos->in_gain;
		for ( j = 0; j < echos->num_delays; j++ ) {
			d_out += echos->delay_buf[echos->counter[j] + echos->pointer[j]] * echos->decay[j];
		}
		/* Adjust the output volume and size to 24 bit */
		d_out = d_out * echos->out_gain;
		out = echos_clip24((LONG) d_out);
		*obuf++ = out * 256;
		/* Mix decay of delays and input */
		for ( j = 0; j < echos->num_delays; j++ ) {
			if ( j == 0 )
				echos->delay_buf[echos->counter[j] + echos->pointer[j]] = d_in;
			else
				echos->delay_buf[echos->counter[j] + echos->pointer[j]] = 
				   echos->delay_buf[echos->counter[j-1] + echos->pointer[j-1]] + d_in;
		}
		/* Adjust the counters */
		for ( j = 0; j < echos->num_delays; j++ )
			echos->counter[j] = 
			   ( echos->counter[j] + 1 ) % echos->samples[j];
	}
	/* processed all samples */
}

/*
 * Drain out reverb lines. 
 */
void echos_drain(effp, obuf, osamp)
eff_t effp;
LONG *obuf;
int *osamp;
{
	echos_t echos = (echos_t) effp->priv;
	double d_in, d_out;
	LONG out;
	int j;
	long done;

	done = 0;
	/* drain out delay samples */
	while ( ( done < *osamp ) && ( done < echos->sumsamples ) ) {
		d_in = 0;
		d_out = 0;
		for ( j = 0; j < echos->num_delays; j++ ) {
			d_out += echos->delay_buf[echos->counter[j] + echos->pointer[j]] * echos->decay[j];
		}
		/* Adjust the output volume and size to 24 bit */
		d_out = d_out * echos->out_gain;
		out = echos_clip24((LONG) d_out);
		*obuf++ = out * 256;
		/* Mix decay of delays and input */
		for ( j = 0; j < echos->num_delays; j++ ) {
			if ( j == 0 )
				echos->delay_buf[echos->counter[j] + echos->pointer[j]] = d_in;
			else
				echos->delay_buf[echos->counter[j] + echos->pointer[j]] = 
				   echos->delay_buf[echos->counter[j-1] + echos->pointer[j-1]];
		}
		/* Adjust the counters */
		for ( j = 0; j < echos->num_delays; j++ )
			echos->counter[j] = 
			   ( echos->counter[j] + 1 ) % echos->samples[j];
		done++;
		echos->sumsamples--;
	};
	/* samples played, it remains */
	*osamp = done;
}

/*
 * Clean up reverb effect.
 */
void echos_stop(effp)
eff_t effp;
{
	echos_t echos = (echos_t) effp->priv;

	free((char *) echos->delay_buf);
	echos->delay_buf = (double *) -1;   /* guaranteed core dump */
}