2 * Copyright (C) 2008 Andre Noll <maan@systemlinux.org>
4 * Licensed under the GPL v2. For licencing details see COPYING.
7 /** \file amp_filter.c Paraslash's amplify filter. */
10 #include "amp_filter.cmdline.h"
18 /** The size of the output data buffer. */
19 #define AMP_CHUNK_SIZE 40960
21 extern char *stat_item_values[NUM_STAT_ITEMS];
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. */
31 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
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);
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);
48 static void amp_close(struct filter_node *fn)
50 free(fn->private_data);
54 static int amp_parse_config(int argc, char **argv, void **config)
56 struct amp_filter_args_info *amp_conf = para_calloc(sizeof(*amp_conf));
57 int ret = -E_AMP_SYNTAX;
59 if (amp_cmdline_parser(argc, argv, amp_conf))
61 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
62 if (amp_conf->amp_arg < 0)
64 PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n",
65 amp_conf->amp_arg, amp_conf->amp_arg / 64.0 + 1.0);
73 static void amp_open(struct filter_node *fn)
75 struct private_amp_data *pad = para_calloc(sizeof(*pad));
78 fn->private_data = pad;
79 if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION]) {
80 int i = SI_AMPLIFICATION;
81 char *s = stat_item_values[i] + strlen(status_item_list[i]) + 1;
82 sscanf(s, "%u", &pad->amp);
84 pad->amp = pad->conf->amp_arg;
85 fn->bufsize = AMP_CHUNK_SIZE;
86 fn->buf = para_malloc(fn->bufsize);
90 * The init function of the amplify filter.
92 * \param f Pointer to the struct to initialize.
94 void amp_filter_init(struct filter *f)
96 struct amp_filter_args_info dummy;
98 amp_cmdline_parser_init(&dummy);
100 f->close = amp_close;
101 f->convert = amp_convert;
102 f->parse_config = amp_parse_config;
103 f->help = (struct ggo_help) {
104 .short_help = amp_filter_args_info_help,
105 .detailed_help = amp_filter_args_info_detailed_help