dd77de8153d917f46f75df6ced1b580b55dd1386
[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 #include "audiod.h"
20
21 /** The size of the output data buffer. */
22 #define COMPRESS_CHUNK_SIZE 40960
23
24 extern char *stat_item_values[NUM_STAT_ITEMS];
25
26 /** Data specific to the compress filter. */
27 struct private_compress_data {
28 /** The current multiplier. */
29 unsigned current_gain;
30 /** Points to the configuration data for this instance of the compress filter. */
31 struct compress_filter_args_info *conf;
32 /** Maximal admissible gain. */
33 unsigned max_gain;
34 /** Number of samples already seen. */
35 unsigned num_samples;
36 /** Absolute value of the maximal sample in the current block. */
37 unsigned peak;
38 /** Amplification factor. */
39 unsigned amp;
40 };
41
42 static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
43 {
44 size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
45 (fn->bufsize - fn->loaded) / 2 * 2);
46 struct private_compress_data *pcd = fn->private_data;
47 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
48 unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
49 mask = (1 << pcd->conf->blocksize_arg) - 1;
50
51 if (!length)
52 return 0;
53 for (i = 0; i < length / 2; i++) {
54 /* be careful in that heat, my dear */
55 int sample = *ip++, adjusted_sample = (PARA_ABS(sample) * (64 + pcd->amp)) >> 6;
56
57 adjusted_sample = (adjusted_sample * pcd->current_gain) >> gain_shift;
58 if (unlikely(adjusted_sample > 32767)) { /* clip */
59 PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
60 sample, adjusted_sample);
61 adjusted_sample = 32767;
62 pcd->current_gain = (3 * pcd->current_gain +
63 (1 << pcd->conf->inertia_arg)) / 4;
64 pcd->peak = 0;
65 } else
66 pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
67 *op++ = sample >= 0? adjusted_sample : -adjusted_sample;
68 if (likely(++pcd->num_samples & mask))
69 continue;
70 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
71 // pcd->peak);
72 if (pcd->peak < pcd->conf->target_level_arg) {
73 if (pcd->current_gain < pcd->max_gain)
74 pcd->current_gain++;
75 } else
76 pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
77 1 << pcd->conf->inertia_arg);
78 pcd->peak = 0;
79 }
80 fn->loaded += length;
81 return length;
82 }
83
84 static void close_compress(struct filter_node *fn)
85 {
86 free(fn->private_data);
87 free(fn->buf);
88 }
89
90 static void *compress_parse_config(int argc, char **argv)
91 {
92 struct compress_filter_args_info *ret = para_calloc(sizeof(struct compress_filter_args_info));
93 if (!compress_cmdline_parser(argc, argv, ret))
94 return ret;
95 free(ret);
96 return NULL;
97 }
98
99 static void open_compress(struct filter_node *fn)
100 {
101 struct private_compress_data *pcd = para_calloc(
102 sizeof(struct private_compress_data));
103 pcd->conf = fn->conf;
104 fn->private_data = pcd;
105 fn->bufsize = COMPRESS_CHUNK_SIZE;
106 fn->buf = para_malloc(fn->bufsize);
107 pcd->current_gain = 1 << pcd->conf->inertia_arg;
108 pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
109 if (stat_item_values[SI_AMPLIFICATION])
110 sscanf(stat_item_values[SI_AMPLIFICATION], "%u", &pcd->amp);
111 PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n", pcd->amp,
112 pcd->amp / 64.0 + 1.0);
113 }
114
115 /**
116 * The init function of the compress filter.
117 *
118 * \param f Pointer to the struct to initialize.
119 */
120 void compress_init(struct filter *f)
121 {
122 f->open = open_compress;
123 f->close = close_compress;
124 f->convert = compress;
125 f->print_help = compress_cmdline_parser_print_help;
126 f->parse_config = compress_parse_config;
127 }