update audiod help text
[paraslash.git] / compress.c
1 /*
2 * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18
19 /** \file compress.c paraslash's dynamic audio range compressor */
20
21 /*
22 * Used ideas of AudioCompress, (C) 2002-2004 M. Hari Nezumi <magenta@trikuare.cx>
23 */
24
25 #include "para.h"
26 #include "compress_filter.cmdline.h"
27 #include "list.h"
28 #include "filter.h"
29 #include "string.h"
30
31 /** the size of the output data buffer */
32 #define COMPRESS_CHUNK_SIZE 40960
33
34 /** data specific to the compress filter */
35 struct private_compress_data {
36 /** the current multiplier */
37 unsigned current_gain;
38 /** points to the configuration data for this instance of the compress filter */
39 struct compress_filter_args_info *conf;
40 /** minimal admissible gain */
41 unsigned min_gain;
42 /** maximal admissible gain */
43 unsigned max_gain;
44 /** number of samples already seen */
45 unsigned num_samples;
46 /** absolute value of the maximal sample in the current block */
47 unsigned peak;
48 };
49
50 static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
51 {
52 size_t i, length = MIN((inbuf_len / 2) * 2, (fn->bufsize - fn->loaded) / 2 * 2);
53 struct private_compress_data *pcd = fn->private_data;
54 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
55 unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
56 mask = (1 << pcd->conf->blocksize_arg) - 1;
57
58 if (!length)
59 return 0;
60 for (i = 0; i < length / 2; i++) {
61 /* be careful in that heat, my dear */
62 int sample = *ip++, adjusted_sample;
63
64 if (sample > 0) {
65 adjusted_sample = (sample * pcd->current_gain)
66 >> gain_shift;
67 if (unlikely(adjusted_sample > 32767)) {
68 adjusted_sample = 32767;
69 pcd->current_gain = (pcd->current_gain +
70 (1 << pcd->conf->inertia_arg)) / 2;
71 pcd->peak = 0;
72 } else
73 if (adjusted_sample > pcd->peak)
74 pcd->peak = sample;
75 } else {
76 adjusted_sample = -((-sample * pcd->current_gain)
77 >> gain_shift);
78 if (unlikely(adjusted_sample < -32768)) {
79 adjusted_sample = -32768;
80 pcd->current_gain = (pcd->current_gain +
81 (1 << pcd->conf->inertia_arg)) / 2;
82 pcd->peak = 0;
83 } else
84 if (-adjusted_sample > pcd->peak)
85 pcd->peak = -adjusted_sample;
86 }
87 *op++ = adjusted_sample;
88 if (likely(++pcd->num_samples & mask))
89 continue;
90 if (pcd->peak < pcd->conf->target_level_arg) {
91 if (pcd->current_gain < pcd->max_gain)
92 pcd->current_gain++;
93 } else {
94 if (pcd->current_gain > pcd->min_gain + 1)
95 pcd->current_gain -= 2;
96 }
97 // PARA_DEBUG_LOG("gain: %lu, peak: %d\n", pcd->current_gain,
98 // pcd->peak);
99 pcd->peak = 0;
100 // PARA_INFO_LOG("sample: %lu\n", ABS(sample));
101 }
102 fn->loaded += length;
103 return length;
104 }
105
106 static void close_compress(struct filter_node *fn)
107 {
108 free(fn->private_data);
109 free(fn->buf);
110 }
111
112 static void *compress_parse_config(int argc, char **argv)
113 {
114 struct compress_filter_args_info *ret = para_calloc(sizeof(struct compress_filter_args_info));
115 if (!compress_cmdline_parser(argc, argv, ret))
116 return ret;
117 free(ret);
118 return NULL;
119 }
120
121 static void open_compress(struct filter_node *fn)
122 {
123 struct private_compress_data *pcd = para_calloc(
124 sizeof(struct private_compress_data));
125 pcd->conf = fn->conf;
126 fn->private_data = pcd;
127 fn->bufsize = COMPRESS_CHUNK_SIZE;
128 fn->buf = para_malloc(fn->bufsize);
129 pcd->current_gain = 1 << pcd->conf->inertia_arg;
130 pcd->min_gain = 1 << (pcd->conf->inertia_arg - pcd->conf->aggressiveness_arg);
131 pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
132 }
133
134 /** the init function of the compress filter */
135 void compress_init(struct filter *f)
136 {
137 f->open = open_compress;
138 f->close = close_compress;
139 f->convert = compress;
140 f->print_help = compress_cmdline_parser_print_help;
141 f->parse_config = compress_parse_config;
142 }