392fff6547c12cb7aa6c1abd62260526171be23b
[paraslash.git] / amp_filter.c
1 /*
2 * Copyright (C) 2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file amp.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 "filter.h"
14 #include "string.h"
15 #include "error.h"
16
17 /** The size of the output data buffer. */
18 #define AMP_CHUNK_SIZE 40960
19
20 extern char *stat_item_values[NUM_STAT_ITEMS];
21
22 /** Data specific to the amplify filter. */
23 struct private_amp_data {
24 /** Points to the configuration data for this instance of this filter. */
25 struct amp_filter_args_info *conf;
26 /** Amplification factor. */
27 unsigned amp;
28 };
29
30 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
31 {
32 size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
33 (fn->bufsize - fn->loaded) / 2 * 2);
34 struct private_amp_data *pad = fn->private_data;
35 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
36
37 if (!length)
38 return 0;
39 for (i = 0; i < length / 2; i++) {
40 int x = (PARA_ABS(*ip) * (64 + pad->amp)) >> 6;
41 *op++ = *ip++ > 0? PARA_MIN(x, 32767) : PARA_MAX(-x, -32768);
42 }
43 fn->loaded += length;
44 return length;
45 }
46
47 static void amp_close(struct filter_node *fn)
48 {
49 free(fn->private_data);
50 free(fn->buf);
51 }
52
53 static void *amp_parse_config(int argc, char **argv)
54 {
55 struct amp_filter_args_info *conf = para_calloc(sizeof(*conf));
56
57 if (amp_cmdline_parser(argc, argv, conf))
58 goto err;
59 if (conf->amp_arg < 0)
60 goto err;
61 PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n", conf->amp_arg,
62 conf->amp_arg / 64.0 + 1.0);
63 return conf;
64 err:
65 free(conf);
66 return NULL;
67 }
68
69 static void amp_open(struct filter_node *fn)
70 {
71 struct private_amp_data *pad = para_calloc(sizeof(*pad));
72
73 pad->conf = fn->conf;
74 fn->private_data = pad;
75 if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION]) {
76 int i = SI_AMPLIFICATION;
77 char *s = stat_item_values[i] + strlen(status_item_list[i]) + 1;
78 sscanf(s, "%u", &pad->amp);
79 } else
80 pad->amp = pad->conf->amp_arg;
81 fn->bufsize = AMP_CHUNK_SIZE;
82 fn->buf = para_malloc(fn->bufsize);
83 }
84
85 /**
86 * The init function of the amplify filter.
87 *
88 * \param f Pointer to the struct to initialize.
89 */
90 void amp_init(struct filter *f)
91 {
92 f->open = amp_open;
93 f->close = amp_close;
94 f->convert = amp_convert;
95 f->print_help = amp_cmdline_parser_print_help;
96 f->parse_config = amp_parse_config;
97 }