2 * Copyright (C) 2005-2008 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"
21 /** The size of the output data buffer. */
22 #define COMPRESS_CHUNK_SIZE 40960
24 extern char *stat_item_values
[NUM_STAT_ITEMS
];
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 ssize_t
compress(char *inbuf
, size_t inbuf_len
, struct filter_node
*fn
)
42 size_t i
, length
= PARA_MIN((inbuf_len
/ 2) * 2,
43 (fn
->bufsize
- fn
->loaded
) / 2 * 2);
44 struct private_compress_data
*pcd
= fn
->private_data
;
45 int16_t *ip
= (int16_t *)inbuf
, *op
= (int16_t *)(fn
->buf
+ fn
->loaded
);
46 unsigned gain_shift
= pcd
->conf
->inertia_arg
+ pcd
->conf
->damp_arg
,
47 mask
= (1 << pcd
->conf
->blocksize_arg
) - 1;
51 for (i
= 0; i
< length
/ 2; i
++) {
52 /* be careful in that heat, my dear */
53 int sample
= *ip
++, adjusted_sample
= (PARA_ABS(sample
) *
54 pcd
->current_gain
) >> gain_shift
;
55 if (unlikely(adjusted_sample
> 32767)) { /* clip */
56 PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
57 sample
, adjusted_sample
);
58 adjusted_sample
= 32767;
59 pcd
->current_gain
= (3 * pcd
->current_gain
+
60 (1 << pcd
->conf
->inertia_arg
)) / 4;
63 pcd
->peak
= PARA_MAX(pcd
->peak
, adjusted_sample
);
64 *op
++ = sample
>= 0? adjusted_sample
: -adjusted_sample
;
65 if (likely(++pcd
->num_samples
& mask
))
67 // PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
69 if (pcd
->peak
< pcd
->conf
->target_level_arg
) {
70 if (pcd
->current_gain
< pcd
->max_gain
)
73 pcd
->current_gain
= PARA_MAX(pcd
->current_gain
- 2,
74 1 << pcd
->conf
->inertia_arg
);
81 static void close_compress(struct filter_node
*fn
)
83 free(fn
->private_data
);
87 /** TODO: Add sanity checks */
88 static int compress_parse_config(int argc
, char **argv
, void **config
)
91 struct compress_filter_args_info
*compress_conf
92 = para_calloc(sizeof(*compress_conf
));
94 ret
= -E_COMPRESS_SYNTAX
;
95 if (compress_cmdline_parser(argc
, argv
, compress_conf
))
97 *config
= compress_conf
;
104 static void open_compress(struct filter_node
*fn
)
106 struct private_compress_data
*pcd
= para_calloc(
107 sizeof(struct private_compress_data
));
108 pcd
->conf
= fn
->conf
;
109 fn
->private_data
= pcd
;
110 fn
->bufsize
= COMPRESS_CHUNK_SIZE
;
111 fn
->buf
= para_malloc(fn
->bufsize
);
112 pcd
->current_gain
= 1 << pcd
->conf
->inertia_arg
;
113 pcd
->max_gain
= 1 << (pcd
->conf
->inertia_arg
+ pcd
->conf
->aggressiveness_arg
);
117 * The init function of the compress filter.
119 * \param f Pointer to the struct to initialize.
121 void compress_filter_init(struct filter
*f
)
123 f
->open
= open_compress
;
124 f
->close
= close_compress
;
125 f
->convert
= compress
;
126 f
->print_help
= compress_cmdline_parser_print_help
;
127 f
->parse_config
= compress_parse_config
;