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
= 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;
60 for (i
= 0; i
< length
/ 2; i
++) {
61 /* be careful in that heat, my dear */
62 int sample
= *ip
++, adjusted_sample
;
65 adjusted_sample
= (sample
* pcd
->current_gain
)
67 if (unlikely(adjusted_sample
> 32767)) {
68 adjusted_sample
= 32767;
69 pcd
->current_gain
= (pcd
->current_gain
+
70 (1 << pcd
->conf
->inertia_arg
)) / 2;
73 if (adjusted_sample
> pcd
->peak
)
76 adjusted_sample
= -((-sample
* pcd
->current_gain
)
78 if (unlikely(adjusted_sample
< -32768)) {
79 adjusted_sample
= -32768;
80 pcd
->current_gain
= (pcd
->current_gain
+
81 (1 << pcd
->conf
->inertia_arg
)) / 2;
84 if (-adjusted_sample
> pcd
->peak
)
85 pcd
->peak
= -adjusted_sample
;
87 *op
++ = adjusted_sample
;
88 if (likely(++pcd
->num_samples
& mask
))
90 if (pcd
->peak
< pcd
->conf
->target_level_arg
) {
91 if (pcd
->current_gain
< pcd
->max_gain
)
94 if (pcd
->current_gain
> pcd
->min_gain
+ 1)
95 pcd
->current_gain
-= 2;
97 // PARA_DEBUG_LOG("gain: %lu, peak: %d\n", pcd->current_gain,
100 // PARA_INFO_LOG("sample: %lu\n", ABS(sample));
102 fn
->loaded
+= length
;
106 static void close_compress(struct filter_node
*fn
)
108 free(fn
->private_data
);
112 static void *compress_parse_config(int argc
, char **argv
)
114 struct compress_filter_args_info
*ret
= para_calloc(sizeof(struct compress_filter_args_info
));
115 if (!compress_cmdline_parser(argc
, argv
, ret
))
121 static void open_compress(struct filter_node
*fn
)
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
);
134 /** the init function of the compress filter */
135 void compress_init(struct filter
*f
)
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
;