2 * Copyright (C) 2005-2008 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file compress.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"
20 /** The size of the output data buffer. */
21 #define COMPRESS_CHUNK_SIZE 40960
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. */
31 /** Number of samples already seen. */
33 /** Absolute value of the maximal sample in the current block. */
37 static ssize_t
compress(char *inbuf
, size_t inbuf_len
, struct filter_node
*fn
)
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;
48 for (i
= 0; i
< length
/ 2; i
++) {
49 /* be careful in that heat, my dear */
50 int sample
= *ip
++, adjusted_sample
;
52 adjusted_sample
= (PARA_ABS(sample
) * pcd
->current_gain
)
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;
62 pcd
->peak
= PARA_MAX(pcd
->peak
, adjusted_sample
);
63 *op
++ = sample
>= 0? adjusted_sample
: -adjusted_sample
;
64 if (likely(++pcd
->num_samples
& mask
))
66 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
68 if (pcd
->peak
< pcd
->conf
->target_level_arg
) {
69 if (pcd
->current_gain
< pcd
->max_gain
)
72 pcd
->current_gain
= PARA_MAX(pcd
->current_gain
- 2,
73 1 << pcd
->conf
->inertia_arg
);
80 static void close_compress(struct filter_node
*fn
)
82 free(fn
->private_data
);
86 static void *compress_parse_config(int argc
, char **argv
)
88 struct compress_filter_args_info
*ret
= para_calloc(sizeof(struct compress_filter_args_info
));
89 if (!compress_cmdline_parser(argc
, argv
, ret
))
95 static void open_compress(struct filter_node
*fn
)
97 struct private_compress_data
*pcd
= para_calloc(
98 sizeof(struct private_compress_data
));
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
);
108 * The init function of the compress filter.
110 * \param f Pointer to the struct to initialize.
112 void compress_init(struct filter
*f
)
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
;