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>
14 #include "compress_filter.cmdline.h"
22 /** The size of the output data buffer. */
23 #define COMPRESS_CHUNK_SIZE 40960
25 extern char *stat_item_values[NUM_STAT_ITEMS];
27 /** Data specific to the compress filter. */
28 struct private_compress_data {
29 /** The current multiplier. */
30 unsigned current_gain;
31 /** Points to the configuration data for this instance of the compress filter. */
32 struct compress_filter_args_info *conf;
33 /** Maximal admissible gain. */
35 /** Number of samples already seen. */
37 /** Absolute value of the maximal sample in the current block. */
41 static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
43 size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
44 (fn->bufsize - fn->loaded) / 2 * 2);
45 struct private_compress_data *pcd = fn->private_data;
46 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
47 unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
48 mask = (1 << pcd->conf->blocksize_arg) - 1;
52 for (i = 0; i < length / 2; i++) {
53 /* be careful in that heat, my dear */
54 int sample = *ip++, adjusted_sample = (PARA_ABS(sample) *
55 pcd->current_gain) >> gain_shift;
56 if (unlikely(adjusted_sample > 32767)) { /* clip */
57 PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
58 sample, adjusted_sample);
59 adjusted_sample = 32767;
60 pcd->current_gain = (3 * pcd->current_gain +
61 (1 << pcd->conf->inertia_arg)) / 4;
64 pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
65 *op++ = sample >= 0? adjusted_sample : -adjusted_sample;
66 if (likely(++pcd->num_samples & mask))
68 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
70 if (pcd->peak < pcd->conf->target_level_arg) {
71 if (pcd->current_gain < pcd->max_gain)
74 pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
75 1U << pcd->conf->inertia_arg);
82 static void close_compress(struct filter_node *fn)
84 free(fn->private_data);
88 /** TODO: Add sanity checks */
89 static int compress_parse_config(int argc, char **argv, void **config)
92 struct compress_filter_args_info *compress_conf
93 = para_calloc(sizeof(*compress_conf));
95 ret = -E_COMPRESS_SYNTAX;
96 if (compress_cmdline_parser(argc, argv, compress_conf))
98 *config = compress_conf;
105 static void open_compress(struct filter_node *fn)
107 struct private_compress_data *pcd = para_calloc(
108 sizeof(struct private_compress_data));
109 pcd->conf = fn->conf;
110 fn->private_data = pcd;
111 fn->bufsize = COMPRESS_CHUNK_SIZE;
112 fn->buf = para_malloc(fn->bufsize);
113 pcd->current_gain = 1 << pcd->conf->inertia_arg;
114 pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
118 * The init function of the compress filter.
120 * \param f Pointer to the struct to initialize.
122 void compress_filter_init(struct filter *f)
124 struct compress_filter_args_info dummy;
126 compress_cmdline_parser_init(&dummy);
127 f->open = open_compress;
128 f->close = close_compress;
129 f->convert = compress;
130 f->parse_config = compress_parse_config;
131 f->help = (struct ggo_help) {
132 .short_help = compress_filter_args_info_help,
133 .detailed_help = compress_filter_args_info_detailed_help