2 * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
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>
16 #include "filter_cmd.lsg.h"
20 #include "buffer_tree.h"
25 #define U32_OPTVAL(_opt, _lpr) (FILTER_CMD_OPT_UINT32_VAL(COMPRESS, _opt, _lpr))
27 /** Data specific to the compress filter. */
28 struct private_compress_data {
29 /** The current multiplier. */
30 unsigned current_gain;
31 /** Maximal admissible gain. */
33 /** Number of samples already seen. */
35 /** Absolute value of the maximal sample in the current block. */
39 static void compress_close(struct filter_node *fn)
41 free(fn->private_data);
44 static int compress_post_select(__a_unused struct sched *s, void *context)
46 struct filter_node *fn = context;
47 struct private_compress_data *pcd = fn->private_data;
48 struct btr_node *btrn = fn->btrn;
49 bool inplace = btr_inplace_ok(btrn);
54 uint32_t inertia = U32_OPTVAL(INERTIA, fn->lpr);
55 unsigned gain_shift = inertia + U32_OPTVAL(DAMP, fn->lpr),
56 mask = (1 << U32_OPTVAL(BLOCKSIZE, fn->lpr)) - 1;
59 ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
64 btr_merge(btrn, fn->min_iqs);
65 length = btr_next_buffer(btrn, &inbuf) & ~(size_t)1;
66 if (length == 0) { /* eof and 1 byte available */
67 ret = -E_COMPRESS_EOF;
70 ip = (int16_t *)inbuf;
74 op = para_malloc(length);
75 for (i = 0; i < length / 2; i++) {
76 /* be careful in that heat, my dear */
84 sample *= pcd->current_gain;
85 sample >>= gain_shift;
86 if (sample > 32767) { /* clip */
88 pcd->current_gain = (3 * pcd->current_gain +
91 } else if (sample > pcd->peak)
93 op[i] = neg? -sample : sample;
94 if (++pcd->num_samples & mask)
96 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
98 if (pcd->peak < U32_OPTVAL(TARGET_LEVEL, fn->lpr)) {
99 if (pcd->current_gain < pcd->max_gain)
102 pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
107 btr_pushdown_one(btrn);
109 btr_consume(btrn, length);
110 btr_add_output((char *)op, length, btrn);
115 btr_remove_node(&fn->btrn);
119 static void compress_open(struct filter_node *fn)
121 struct private_compress_data *pcd = para_calloc(sizeof(*pcd));
122 uint32_t inertia = U32_OPTVAL(INERTIA, fn->lpr);
123 uint32_t aggressiveness = U32_OPTVAL(AGGRESSIVENESS, fn->lpr);
125 fn->private_data = pcd;
126 fn->min_iqs = 2; /* 16 bit audio */
127 pcd->current_gain = 1U << inertia;
128 pcd->max_gain = 1U << (inertia + aggressiveness);
131 const struct filter lsg_filter_cmd_com_compress_user_data = {
132 .open = compress_open,
133 .close = compress_close,
134 .pre_select = generic_filter_pre_select,
135 .post_select = compress_post_select,