audiod.c: Fix stat task restarting.
[paraslash.git] / compress.c
1 /*
2 * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file compress.c Paraslash's dynamic audio range compressor. */
8
9 /*
10 * Uses ideas of AudioCompress, (C) 2002-2004 M. Hari Nezumi <magenta@trikuare.cx>
11 */
12
13 #include "para.h"
14 #include "compress_filter.cmdline.h"
15 #include "list.h"
16 #include "sched.h"
17 #include "filter.h"
18 #include "string.h"
19
20 /** The size of the output data buffer. */
21 #define COMPRESS_CHUNK_SIZE 40960
22
23 /** Data specific to the compress filter. */
24 struct private_compress_data {
25 /** The current multiplier. */
26 unsigned current_gain;
27 /** Points to the configuration data for this instance of the compress filter. */
28 struct compress_filter_args_info *conf;
29 /** Maximal admissible gain. */
30 unsigned max_gain;
31 /** Number of samples already seen. */
32 unsigned num_samples;
33 /** Absolute value of the maximal sample in the current block. */
34 unsigned peak;
35 };
36
37 static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
38 {
39 size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
40 (fn->bufsize - fn->loaded) / 2 * 2);
41 struct private_compress_data *pcd = fn->private_data;
42 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
43 unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
44 mask = (1 << pcd->conf->blocksize_arg) - 1;
45
46 if (!length)
47 return 0;
48 for (i = 0; i < length / 2; i++) {
49 /* be careful in that heat, my dear */
50 int sample = *ip++, adjusted_sample;
51
52 adjusted_sample = (PARA_ABS(sample) * pcd->current_gain)
53 >> gain_shift;
54 if (unlikely(adjusted_sample > 32767)) { /* clip */
55 PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
56 sample, adjusted_sample);
57 adjusted_sample = 32767;
58 pcd->current_gain = (3 * pcd->current_gain +
59 (1 << pcd->conf->inertia_arg)) / 4;
60 pcd->peak = 0;
61 } else
62 pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
63 *op++ = sample >= 0? adjusted_sample : -adjusted_sample;
64 if (likely(++pcd->num_samples & mask))
65 continue;
66 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
67 // pcd->peak);
68 if (pcd->peak < pcd->conf->target_level_arg) {
69 if (pcd->current_gain < pcd->max_gain)
70 pcd->current_gain++;
71 } else
72 pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
73 1 << pcd->conf->inertia_arg);
74 pcd->peak = 0;
75 }
76 fn->loaded += length;
77 return length;
78 }
79
80 static void close_compress(struct filter_node *fn)
81 {
82 free(fn->private_data);
83 free(fn->buf);
84 }
85
86 static void *compress_parse_config(int argc, char **argv)
87 {
88 struct compress_filter_args_info *ret = para_calloc(sizeof(struct compress_filter_args_info));
89 if (!compress_cmdline_parser(argc, argv, ret))
90 return ret;
91 free(ret);
92 return NULL;
93 }
94
95 static void open_compress(struct filter_node *fn)
96 {
97 struct private_compress_data *pcd = para_calloc(
98 sizeof(struct private_compress_data));
99 pcd->conf = fn->conf;
100 fn->private_data = pcd;
101 fn->bufsize = COMPRESS_CHUNK_SIZE;
102 fn->buf = para_malloc(fn->bufsize);
103 pcd->current_gain = 1 << pcd->conf->inertia_arg;
104 pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
105 }
106
107 /**
108 * The init function of the compress filter.
109 *
110 * \param f Pointer to the struct to initialize.
111 */
112 void compress_init(struct filter *f)
113 {
114 f->open = open_compress;
115 f->close = close_compress;
116 f->convert = compress;
117 f->print_help = compress_cmdline_parser_print_help;
118 f->parse_config = compress_parse_config;
119 }