Documentation updates for 0.4.
[paraslash.git] / amp_filter.c
1 /*
2 * Copyright (C) 2009 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file amp_filter.c Paraslash's amplify filter. */
8
9 #include "para.h"
10 #include "amp_filter.cmdline.h"
11 #include "list.h"
12 #include "sched.h"
13 #include "ggo.h"
14 #include "filter.h"
15 #include "string.h"
16 #include "error.h"
17
18 /** The size of the output data buffer. */
19 #define AMP_CHUNK_SIZE 40960
20
21 extern char *stat_item_values[NUM_STAT_ITEMS];
22
23 /** Data specific to the amplify filter. */
24 struct private_amp_data {
25 /** Points to the configuration data for this instance of this filter. */
26 struct amp_filter_args_info *conf;
27 /** Amplification factor. */
28 unsigned amp;
29 };
30
31 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
32 {
33 size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
34 (fn->bufsize - fn->loaded) / 2 * 2);
35 struct private_amp_data *pad = fn->private_data;
36 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
37
38 if (!length)
39 return 0;
40 for (i = 0; i < length / 2; i++) {
41 int x = (PARA_ABS(*ip) * (64 + pad->amp)) >> 6;
42 *op++ = *ip++ > 0? PARA_MIN(x, 32767) : PARA_MAX(-x, -32768);
43 }
44 fn->loaded += length;
45 return length;
46 }
47
48 static void amp_close(struct filter_node *fn)
49 {
50 free(fn->private_data);
51 free(fn->buf);
52 }
53
54 static int amp_parse_config(int argc, char **argv, void **config)
55 {
56 struct amp_filter_args_info *amp_conf = para_calloc(sizeof(*amp_conf));
57 int ret = -E_AMP_SYNTAX;
58
59 if (amp_cmdline_parser(argc, argv, amp_conf))
60 goto err;
61 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
62 if (amp_conf->amp_arg < 0)
63 goto err;
64 PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n",
65 amp_conf->amp_arg, amp_conf->amp_arg / 64.0 + 1.0);
66 *config = amp_conf;
67 return 1;
68 err:
69 free(amp_conf);
70 return ret;
71 }
72
73 static void amp_open(struct filter_node *fn)
74 {
75 struct private_amp_data *pad = para_calloc(sizeof(*pad));
76
77 pad->conf = fn->conf;
78 fn->private_data = pad;
79 if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION])
80 sscanf(stat_item_values[SI_AMPLIFICATION], "%u", &pad->amp);
81 else
82 pad->amp = pad->conf->amp_arg;
83 fn->bufsize = AMP_CHUNK_SIZE;
84 fn->buf = para_malloc(fn->bufsize);
85 }
86
87 /**
88 * The init function of the amplify filter.
89 *
90 * \param f Pointer to the struct to initialize.
91 */
92 void amp_filter_init(struct filter *f)
93 {
94 struct amp_filter_args_info dummy;
95
96 amp_cmdline_parser_init(&dummy);
97 f->open = amp_open;
98 f->close = amp_close;
99 f->convert = amp_convert;
100 f->parse_config = amp_parse_config;
101 f->help = (struct ggo_help) {
102 .short_help = amp_filter_args_info_help,
103 .detailed_help = amp_filter_args_info_detailed_help
104 };
105 }