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. */
13 #include "amp_filter.cmdline.h"
17 #include "buffer_tree.h"
22 /** The size of the output data buffer. */
23 #define AMP_CHUNK_SIZE 40960
25 extern char *stat_item_values[NUM_STAT_ITEMS];
27 /** Data specific to the amplify filter. */
28 struct private_amp_data {
29 /** Points to the configuration data for this instance of this filter. */
30 struct amp_filter_args_info *conf;
31 /** Amplification factor. */
35 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
37 size_t i, length = PARA_MIN((inbuf_len / 2),
38 (fn->bufsize - fn->loaded) / 2);
39 struct private_amp_data *pad = fn->private_data;
40 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
41 int factor = 64 + pad->amp;
47 memcpy(op, ip, length * 2);
50 for (i = 0; i < length; i++) {
51 int x = (ip[i] * factor) >> 6;
55 op[i] = (x >= 32768)? 32767 : -32768;
58 fn->loaded += length * 2;
62 static void amp_close(struct filter_node *fn)
64 free(fn->private_data);
68 static int amp_parse_config(int argc, char **argv, void **config)
70 struct amp_filter_args_info *amp_conf = para_calloc(sizeof(*amp_conf));
71 int ret = -E_AMP_SYNTAX;
73 if (amp_cmdline_parser(argc, argv, amp_conf))
75 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
76 if (amp_conf->amp_arg < 0)
78 PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n",
79 amp_conf->amp_arg, amp_conf->amp_arg / 64.0 + 1.0);
87 static void amp_open(struct filter_node *fn)
89 struct private_amp_data *pad = para_calloc(sizeof(*pad));
92 fn->private_data = pad;
93 if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION])
94 sscanf(stat_item_values[SI_AMPLIFICATION], "%u", &pad->amp);
96 pad->amp = pad->conf->amp_arg;
97 fn->bufsize = AMP_CHUNK_SIZE;
98 fn->buf = para_malloc(fn->bufsize);
102 * The init function of the amplify filter.
104 * \param f Pointer to the struct to initialize.
106 void amp_filter_init(struct filter *f)
108 struct amp_filter_args_info dummy;
110 amp_cmdline_parser_init(&dummy);
112 f->close = amp_close;
113 f->convert = amp_convert;
114 f->parse_config = amp_parse_config;
115 f->help = (struct ggo_help) {
116 .short_help = amp_filter_args_info_help,
117 .detailed_help = amp_filter_args_info_detailed_help