2 * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file compress_filter.c Paraslash's dynamic audio range compressor. */
10 * Uses ideas of AudioCompress, (C) 2002-2004 M. Hari Nezumi <magenta@trikuare.cx>
17 #include "compress_filter.cmdline.h"
21 #include "buffer_tree.h"
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. */
34 /** Number of samples already seen. */
36 /** Absolute value of the maximal sample in the current block. */
40 static void compress_close(struct filter_node *fn)
42 free(fn->private_data);
45 static void compress_post_select(__a_unused struct sched *s, struct task *t)
47 struct filter_node *fn = container_of(t, struct filter_node, task);
48 struct private_compress_data *pcd = fn->private_data;
49 struct btr_node *btrn = fn->btrn;
50 bool inplace = btr_inplace_ok(btrn);
55 unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
56 mask = (1 << pcd->conf->blocksize_arg) - 1;
61 ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
66 btr_merge(btrn, fn->min_iqs);
67 length = btr_next_buffer(btrn, &inbuf) & ~(size_t)1;
68 if (length == 0) { /* eof and 1 byte available */
69 ret = -E_COMPRESS_EOF;
72 ip = (int16_t *)inbuf;
76 op = para_malloc(length);
77 for (i = 0; i < length / 2; i++) {
78 /* be careful in that heat, my dear */
79 int sample = *ip++, adjusted_sample = (PARA_ABS(sample) *
80 pcd->current_gain) >> gain_shift;
81 if (adjusted_sample > 32767) { /* clip */
82 PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
83 sample, adjusted_sample);
84 adjusted_sample = 32767;
85 pcd->current_gain = (3 * pcd->current_gain +
86 (1 << pcd->conf->inertia_arg)) / 4;
89 pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
90 op[i] = sample >= 0? adjusted_sample : -adjusted_sample;
91 if (++pcd->num_samples & mask)
93 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
95 if (pcd->peak < pcd->conf->target_level_arg) {
96 if (pcd->current_gain < pcd->max_gain)
99 pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
100 1U << pcd->conf->inertia_arg);
104 btr_pushdown_one(btrn);
106 btr_consume(btrn, length);
107 btr_add_output((char *)op, length, btrn);
113 btr_remove_node(btrn);
116 /** TODO: Add sanity checks */
117 static int compress_parse_config(int argc, char **argv, void **config)
120 struct compress_filter_args_info *compress_conf
121 = para_calloc(sizeof(*compress_conf));
123 ret = -E_COMPRESS_SYNTAX;
124 if (compress_cmdline_parser(argc, argv, compress_conf))
126 *config = compress_conf;
133 static void compress_open(struct filter_node *fn)
135 struct private_compress_data *pcd = para_calloc(
136 sizeof(struct private_compress_data));
137 pcd->conf = fn->conf;
138 fn->private_data = pcd;
139 fn->min_iqs = 2; /* 16 bit audio */
140 pcd->current_gain = 1 << pcd->conf->inertia_arg;
141 pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
144 static void compress_free_config(void *conf)
146 compress_cmdline_parser_free(conf);
150 * The init function of the compress filter.
152 * \param f Pointer to the struct to initialize.
154 void compress_filter_init(struct filter *f)
156 struct compress_filter_args_info dummy;
158 compress_cmdline_parser_init(&dummy);
159 f->open = compress_open;
160 f->close = compress_close;
161 f->pre_select = generic_filter_pre_select;
162 f->post_select = compress_post_select;
163 f->parse_config = compress_parse_config;
164 f->free_config = compress_free_config;
165 f->help = (struct ggo_help) {
166 .short_help = compress_filter_args_info_help,
167 .detailed_help = compress_filter_args_info_detailed_help