2 * Copyright (C) 2005-2006 Andre Noll <maan@systemlinux.org>
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.
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.
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.
19 /** \file compress.c paraslash's dynamic audio range compressor */
22 * Used ideas of AudioCompress, (C) 2002-2004 M. Hari Nezumi <magenta@trikuare.cx>
26 #include "compress_filter.cmdline.h"
31 /** the size of the output data buffer */
32 #define COMPRESS_CHUNK_SIZE 40960
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 */
42 /** maximal admissible gain */
44 /** number of samples already seen */
46 /** absolute value of the maximal sample in the current block */
50 static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
52 size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
53 (fn->bufsize - fn->loaded) / 2 * 2);
54 struct private_compress_data *pcd = fn->private_data;
55 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
56 unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
57 mask = (1 << pcd->conf->blocksize_arg) - 1;
61 for (i = 0; i < length / 2; i++) {
62 /* be careful in that heat, my dear */
63 int sample = *ip++, adjusted_sample;
66 adjusted_sample = (sample * pcd->current_gain)
68 if (unlikely(adjusted_sample > 32767)) {
69 adjusted_sample = 32767;
70 pcd->current_gain = (3 * pcd->current_gain +
71 (1 << pcd->conf->inertia_arg)) / 4;
74 if (adjusted_sample > pcd->peak)
77 adjusted_sample = -((-sample * pcd->current_gain)
79 if (unlikely(adjusted_sample < -32768)) {
80 adjusted_sample = -32768;
81 pcd->current_gain = (3 * pcd->current_gain +
82 (1 << pcd->conf->inertia_arg)) / 4;
85 if (-adjusted_sample > pcd->peak)
86 pcd->peak = -adjusted_sample;
88 *op++ = adjusted_sample;
89 if (likely(++pcd->num_samples & mask))
91 if (pcd->peak < pcd->conf->target_level_arg) {
92 if (pcd->current_gain < pcd->max_gain)
95 if (pcd->current_gain > pcd->min_gain + 1)
96 pcd->current_gain -= 2;
98 // PARA_DEBUG_LOG("gain: %lu, peak: %d\n", pcd->current_gain,
101 // PARA_INFO_LOG("sample: %lu\n", ABS(sample));
103 fn->loaded += length;
107 static void close_compress(struct filter_node *fn)
109 free(fn->private_data);
113 static void *compress_parse_config(int argc, char **argv)
115 struct compress_filter_args_info *ret = para_calloc(sizeof(struct compress_filter_args_info));
116 if (!compress_cmdline_parser(argc, argv, ret))
122 static void open_compress(struct filter_node *fn)
124 struct private_compress_data *pcd = para_calloc(
125 sizeof(struct private_compress_data));
126 pcd->conf = fn->conf;
127 fn->private_data = pcd;
128 fn->bufsize = COMPRESS_CHUNK_SIZE;
129 fn->buf = para_malloc(fn->bufsize);
130 pcd->current_gain = 1 << pcd->conf->inertia_arg;
131 pcd->min_gain = 1 << (pcd->conf->inertia_arg - pcd->conf->aggressiveness_arg);
132 pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
135 /** the init function of the compress filter */
136 void compress_init(struct filter *f)
138 f->open = open_compress;
139 f->close = close_compress;
140 f->convert = compress;
141 f->print_help = compress_cmdline_parser_print_help;
142 f->parse_config = compress_parse_config;