2 * Copyright (C) 2009 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. */
12 #include "amp_filter.cmdline.h"
20 /** The size of the output data buffer. */
21 #define AMP_CHUNK_SIZE 40960
23 extern char *stat_item_values[NUM_STAT_ITEMS];
25 /** Data specific to the amplify filter. */
26 struct private_amp_data {
27 /** Points to the configuration data for this instance of this filter. */
28 struct amp_filter_args_info *conf;
29 /** Amplification factor. */
33 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
35 size_t i, length = PARA_MIN((inbuf_len / 2),
36 (fn->bufsize - fn->loaded) / 2);
37 struct private_amp_data *pad = fn->private_data;
38 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
39 int factor = 64 + pad->amp;
45 memcpy(op, ip, length * 2);
48 for (i = 0; i < length; i++) {
49 int x = (ip[i] * factor) >> 6;
53 op[i] = (x >= 32768)? 32767 : -32768;
56 fn->loaded += length * 2;
60 static void amp_close(struct filter_node *fn)
62 free(fn->private_data);
66 static int amp_parse_config(int argc, char **argv, void **config)
68 struct amp_filter_args_info *amp_conf = para_calloc(sizeof(*amp_conf));
69 int ret = -E_AMP_SYNTAX;
71 if (amp_cmdline_parser(argc, argv, amp_conf))
73 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
74 if (amp_conf->amp_arg < 0)
76 PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n",
77 amp_conf->amp_arg, amp_conf->amp_arg / 64.0 + 1.0);
85 static void amp_open(struct filter_node *fn)
87 struct private_amp_data *pad = para_calloc(sizeof(*pad));
90 fn->private_data = pad;
91 if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION])
92 sscanf(stat_item_values[SI_AMPLIFICATION], "%u", &pad->amp);
94 pad->amp = pad->conf->amp_arg;
95 fn->bufsize = AMP_CHUNK_SIZE;
96 fn->buf = para_malloc(fn->bufsize);
100 * The init function of the amplify filter.
102 * \param f Pointer to the struct to initialize.
104 void amp_filter_init(struct filter *f)
106 struct amp_filter_args_info dummy;
108 amp_cmdline_parser_init(&dummy);
110 f->close = amp_close;
111 f->convert = amp_convert;
112 f->parse_config = amp_parse_config;
113 f->help = (struct ggo_help) {
114 .short_help = amp_filter_args_info_help,
115 .detailed_help = amp_filter_args_info_detailed_help