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 /** The size of the output data buffer. */
27 #define COMPRESS_CHUNK_SIZE 40960
29 /** Data specific to the compress filter. */
30 struct private_compress_data
{
31 /** The current multiplier. */
32 unsigned current_gain
;
33 /** Points to the configuration data for this instance of the compress filter. */
34 struct compress_filter_args_info
*conf
;
35 /** Maximal admissible gain. */
37 /** Number of samples already seen. */
39 /** Absolute value of the maximal sample in the current block. */
43 static ssize_t
compress(char *inbuf
, size_t inbuf_len
, struct filter_node
*fn
)
45 size_t i
, length
= PARA_MIN((inbuf_len
/ 2) * 2,
46 (fn
->bufsize
- fn
->loaded
) / 2 * 2);
47 struct private_compress_data
*pcd
= fn
->private_data
;
48 int16_t *ip
= (int16_t *)inbuf
, *op
= (int16_t *)(fn
->buf
+ fn
->loaded
);
49 unsigned gain_shift
= pcd
->conf
->inertia_arg
+ pcd
->conf
->damp_arg
,
50 mask
= (1 << pcd
->conf
->blocksize_arg
) - 1;
54 for (i
= 0; i
< length
/ 2; i
++) {
55 /* be careful in that heat, my dear */
56 int sample
= *ip
++, adjusted_sample
= (PARA_ABS(sample
) *
57 pcd
->current_gain
) >> gain_shift
;
58 if (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;
66 pcd
->peak
= PARA_MAX(pcd
->peak
, adjusted_sample
);
67 *op
++ = sample
>= 0? adjusted_sample
: -adjusted_sample
;
68 if (++pcd
->num_samples
& mask
)
70 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
72 if (pcd
->peak
< pcd
->conf
->target_level_arg
) {
73 if (pcd
->current_gain
< pcd
->max_gain
)
76 pcd
->current_gain
= PARA_MAX(pcd
->current_gain
- 2,
77 1U << pcd
->conf
->inertia_arg
);
84 static void close_compress(struct filter_node
*fn
)
86 free(fn
->private_data
);
90 /** TODO: Add sanity checks */
91 static int compress_parse_config(int argc
, char **argv
, void **config
)
94 struct compress_filter_args_info
*compress_conf
95 = para_calloc(sizeof(*compress_conf
));
97 ret
= -E_COMPRESS_SYNTAX
;
98 if (compress_cmdline_parser(argc
, argv
, compress_conf
))
100 *config
= compress_conf
;
107 static void open_compress(struct filter_node
*fn
)
109 struct private_compress_data
*pcd
= para_calloc(
110 sizeof(struct private_compress_data
));
111 pcd
->conf
= fn
->conf
;
112 fn
->private_data
= pcd
;
113 fn
->bufsize
= COMPRESS_CHUNK_SIZE
;
114 fn
->buf
= para_malloc(fn
->bufsize
);
115 pcd
->current_gain
= 1 << pcd
->conf
->inertia_arg
;
116 pcd
->max_gain
= 1 << (pcd
->conf
->inertia_arg
+ pcd
->conf
->aggressiveness_arg
);
120 * The init function of the compress filter.
122 * \param f Pointer to the struct to initialize.
124 void compress_filter_init(struct filter
*f
)
126 struct compress_filter_args_info dummy
;
128 compress_cmdline_parser_init(&dummy
);
129 f
->open
= open_compress
;
130 f
->close
= close_compress
;
131 f
->convert
= compress
;
132 f
->parse_config
= compress_parse_config
;
133 f
->help
= (struct ggo_help
) {
134 .short_help
= compress_filter_args_info_help
,
135 .detailed_help
= compress_filter_args_info_detailed_help