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                 int i = SI_AMPLIFICATION;
  81                 char *s = stat_item_values[i] + strlen(status_item_list[i]) + 1;
  82                 sscanf(s, "%u", &pad->amp);
  83         } else
  84                 pad->amp = pad->conf->amp_arg;
  85         fn->bufsize = AMP_CHUNK_SIZE;
  86         fn->buf = para_malloc(fn->bufsize);
  87 }
  88
  89 /**
  90  * The init function of the amplify filter.
  91  *
  92  * \param f Pointer to the struct to initialize.
  93  */
  94 void amp_filter_init(struct filter *f)
  95 {
  96         struct amp_filter_args_info dummy;
  97
  98         amp_cmdline_parser_init(&dummy);
  99         f->open = amp_open;
 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
 106         };
 107 }