File: aksreverb.c

package info (click to toggle)
bristol 0.60.10-3
  • links: PTS, VCS
  • area: main
  • in suites: wheezy
  • size: 15,652 kB
  • sloc: ansic: 124,457; sh: 10,579; makefile: 111
file content (293 lines) | stat: -rw-r--r-- 8,348 bytes parent folder | download | duplicates (3)
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
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293

/*
 *  Diverse Bristol audio routines.
 *  Copyright (c) by Nick Copeland <nickycopeland@hotmail.com> 1996,2012
 *
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 3 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 */

/*#define DEBUG */

#include <math.h>

#include "bristol.h"
#include "aksreverb.h"

#define DELAY		0
#define FEEDBACK	1
#define CROSSOVER	2
#define WETDRY		3
#define LINE1		4

#define OPNAME "AKS Reverb"
#define OPDESCRIPTION "Stereo input/output reverb"
#define PCOUNT 6
#define IOCOUNT 3

#define AKSREVERB_IN_IND 0
#define AKSREVERB_MOD_IND 1
#define AKSREVERB_OUT_IND 2

/*
 * Reset any local memory information.
 */
static int destroy(bristolOP *operator)
{
#ifdef BRISTOL_DBG
	printf("destroy(%x)\n", operator);
#endif

	bristolfree(operator->specs);

	cleanup(operator);

	return(0);
}

/*
 * This is called by the frontend when a parameter is changed.
static int param(param, value)
 */
static int param(bristolOP *operator, bristolOPParams *param,
	unsigned char index, float value)
{
#ifdef DEBUG
	printf("checkParams(%f)\n", value);
#endif

	param->param[index].float_val = value;

	return(0);
}

/*
 * Reset any local memory information.
 */
static int reset(bristolOP *operator, bristolOPParams *param)
{
#ifdef BRISTOL_DBG
	printf("reset(%x)\n", operator);
#endif

	if (param->param[0].mem)
		bristolfree(param->param[0].mem);
	if (param->param[1].mem)
		bristolfree(param->param[1].mem);

	param->param[0].mem = bristolmalloc0(sizeof(float) * HISTSIZE);
	param->param[1].mem = bristolmalloc0(sizeof(float) * HISTSIZE);

	param->param[0].float_val = 0.2;
	param->param[1].float_val = 0.3;
	param->param[2].float_val = 0.3;
	param->param[3].float_val = 0.3;
	param->param[4].float_val = 1.0;
	param->param[5].float_val = 1.0;

	return(0);
}

/*
 * This is going to be a mono reverb with two delay lines. The delay lines
 * will be sized to approximate the 25 and 28 ms delay lines from the original
 * although we should allow it to go outside of that range. Should consider
 * implementing a high pass filter to try and cut down on booming from the low
 * end.
 */
static int operate(bristolOP *operator,
	bristolVoice *voice,
	bristolOPParams *param,
	void *lcl)
{
	bristolAKSREVERB *specs;
	bristolAKSREVERBlocal *local = (bristolAKSREVERBlocal *) lcl;
	register float *source, *dest, *lhistory, *rhistory;
	register int count, i, histin1, histin2, delay1, delay2;
	register float crossover, feedback, line1, *mod, fb, co;

	specs = (bristolAKSREVERB *) operator->specs;

	count = specs->spec.io[AKSREVERB_OUT_IND].samplecount;
	source = specs->spec.io[AKSREVERB_IN_IND].buf;
	dest = specs->spec.io[AKSREVERB_OUT_IND].buf;
	mod = specs->spec.io[AKSREVERB_MOD_IND].buf;

	/*
	 * operational parameters. Speed should be a function of depth, ie, if 
	 * depth changes, speed should be adjusted to maintain scan rate.
	 *
	 * Let speed be 10 seconds require to reach the given depth. That can be 
	 * calculated as 441000 samples, so we divide speed by depth * 44100;
	depth = param->param[DEPTH].float_val * 1024;
	speed = param->param[SPEED].float_val * 0.0002 * depth;
	 */
	/*
	 * Let scan be ten seconds to reach gain
	gain = param->param[GAIN].float_val * 1.5;
	scan = param->param[SCAN].float_val * 0.0005 * gain;
	 */
	delay1 = param->param[DELAY].float_val * HISTSIZE;
	delay2 = delay1 * 25 / 28;
	fb = 0.5 - param->param[FEEDBACK].float_val;
	co = 0.5 - param->param[CROSSOVER].float_val;
	line1 = param->param[LINE1].float_val;

	lhistory = param->param[0].mem;
	rhistory = param->param[1].mem;

#ifdef DEBUG
	printf("reverb()\n");
#endif

	histin1 = local->histin1;
	histin2 = local->histin2;

	for (i = 0; i < count; i++) {
		feedback = fb * *mod;
		crossover = co * *mod++;
		/*
		 * Save our current signal into the history buffers. This should 
		 * include a component of feedback and crossover for echo/reverb effect.
		 * It also needs to go through a HPF.
		 */
		lhistory[histin1] =
			lhistory[histin1] * feedback
			+ rhistory[histin2] * crossover
			+ *source;
		rhistory[histin2] =
			rhistory[histin2] * feedback
			+ lhistory[histin1] * crossover
			+ *source++;

		/*
		 * for testing just make the output be the input with delay.
		 */
		if (++histin1 >= delay1)
			histin1 = 0;
		if (++histin2 >= delay2)
			histin2 = 0;

		*dest++ = (lhistory[histin1] + rhistory[histin2]) * line1;
	}

	local->histin1 = histin1;
	local->histin2 = histin2;

	return(0);
}

/*
 * Setup any variables in our OP structure, in our IO structures, and malloc
 * any memory we need.
 */
bristolOP *
aksreverbinit(bristolOP **operator, int index, int samplerate, int samplecount)
{
	bristolAKSREVERB *specs;

	*operator = bristolOPinit(operator, index, samplecount);

#ifdef BRISTOL_DBG
	printf("reverbinit(%x(%x), %i, %i, %i)\n",
		operator, *operator, index, samplerate, samplecount);
#endif

	/*
	 * Then the local parameters specific to this operator. These will be
	 * the same for each operator, but must be inited in the local code.
	 */
	(*operator)->operate = operate;
	(*operator)->destroy = destroy;
	(*operator)->reset = reset;
	(*operator)->param = param;
	(*operator)->flags |= BRISTOL_FX_STEREO;

	specs = (bristolAKSREVERB *) bristolmalloc0(sizeof(bristolAKSREVERB));
	(*operator)->specs = (bristolOPSpec *) specs;
	(*operator)->size = sizeof(bristolAKSREVERB);

	/*
	 * These are specific to this operator, and will need to be altered for
	 * each operator.
	 */
	specs->spec.opname = OPNAME;
	specs->spec.description = OPDESCRIPTION;
	specs->spec.pcount = PCOUNT;
	specs->spec.iocount = IOCOUNT;
	specs->spec.localsize = sizeof(bristolAKSREVERBlocal);

	/*
	 * Now fill in the specs for this operator.
	 */
	specs->spec.param[0].pname = "delay";
	specs->spec.param[0].description= "reverb delay line depth";
	specs->spec.param[0].type = BRISTOL_FLOAT;
	specs->spec.param[0].low = 0;
	specs->spec.param[0].high = 1;
	specs->spec.param[0].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	specs->spec.param[1].pname = "feedback";
	specs->spec.param[1].description = "depth of mono feedback";
	specs->spec.param[1].type = BRISTOL_FLOAT;
	specs->spec.param[1].low = 0;
	specs->spec.param[1].high = 1;
	specs->spec.param[1].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	specs->spec.param[2].pname = "crossfade";
	specs->spec.param[2].description = "depth of stereo feedback signal";
	specs->spec.param[2].type = BRISTOL_FLOAT;
	specs->spec.param[2].low = 0;
	specs->spec.param[2].high = 1;
	specs->spec.param[2].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	specs->spec.param[3].pname = "depth";
	specs->spec.param[3].description = "wet/dry mix";
	specs->spec.param[3].type = BRISTOL_FLOAT;
	specs->spec.param[3].low = 0;
	specs->spec.param[3].high = 1;
	specs->spec.param[3].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	specs->spec.param[4].pname = "line1 gain";
	specs->spec.param[4].description = "mix";
	specs->spec.param[4].type = BRISTOL_FLOAT;
	specs->spec.param[4].low = 0;
	specs->spec.param[4].high = 1;
	specs->spec.param[4].flags = BRISTOL_ROTARY|BRISTOL_SLIDER;

	/*
	 * Now fill in the IO specs.
	 */
	specs->spec.io[0].ioname = "input buffer";
	specs->spec.io[0].description = "input signal";
	specs->spec.io[0].samplerate = samplerate;
	specs->spec.io[0].samplecount = samplecount;
	specs->spec.io[0].flags = BRISTOL_AC|BRISTOL_INPUT;

	specs->spec.io[1].ioname = "output buffer";
	specs->spec.io[1].description = "input signal";
	specs->spec.io[1].samplerate = samplerate;
	specs->spec.io[1].samplecount = samplecount;
	specs->spec.io[1].flags = BRISTOL_AC|BRISTOL_INPUT;

	specs->spec.io[2].ioname = "mod buffer";
	specs->spec.io[2].description = "input signal";
	specs->spec.io[2].samplerate = samplerate;
	specs->spec.io[2].samplecount = samplecount;
	specs->spec.io[2].flags = BRISTOL_AC|BRISTOL_INPUT;

	return(*operator);
}