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 <regex.h>
  10
  11 #include "para.h"
  12 #include "amp_filter.cmdline.h"
  13 #include "list.h"
  14 #include "sched.h"
  15 #include "ggo.h"
  16 #include "filter.h"
  17 #include "string.h"
  18 #include "error.h"
  19
  20 /** The size of the output data buffer. */
  21 #define AMP_CHUNK_SIZE 40960
  22
  23 extern char *stat_item_values[NUM_STAT_ITEMS];
  24
  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. */
  30         unsigned amp;
  31 };
  32
  33 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
  34 {
  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;
  40
  41         if (!length)
  42                 return 0;
  43
  44         if (pad->amp == 0) {
  45                 memcpy(op, ip, length * 2);
  46                 goto out;
  47         }
  48         for (i = 0; i < length; i++) {
  49                 int x = (ip[i] * factor) >> 6;
  50
  51                 op[i] = x;
  52                 if (op[i] != x)
  53                         op[i] = (x >= 32768)? 32767 : -32768;
  54         }
  55 out:
  56         fn->loaded += length * 2;
  57         return length * 2;
  58 }
  59
  60 static void amp_close(struct filter_node *fn)
  61 {
  62         free(fn->private_data);
  63         free(fn->buf);
  64 }
  65
  66 static int amp_parse_config(int argc, char **argv, void **config)
  67 {
  68         struct amp_filter_args_info *amp_conf = para_calloc(sizeof(*amp_conf));
  69         int ret = -E_AMP_SYNTAX;
  70
  71         if (amp_cmdline_parser(argc, argv, amp_conf))
  72                 goto err;
  73         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
  74         if (amp_conf->amp_arg < 0)
  75                 goto err;
  76         PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n",
  77                 amp_conf->amp_arg, amp_conf->amp_arg / 64.0 + 1.0);
  78         *config = amp_conf;
  79         return 1;
  80 err:
  81         free(amp_conf);
  82         return ret;
  83 }
  84
  85 static void amp_open(struct filter_node *fn)
  86 {
  87         struct private_amp_data *pad = para_calloc(sizeof(*pad));
  88
  89         pad->conf = fn->conf;
  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);
  93         else
  94                 pad->amp = pad->conf->amp_arg;
  95         fn->bufsize = AMP_CHUNK_SIZE;
  96         fn->buf = para_malloc(fn->bufsize);
  97 }
  98
  99 /**
 100  * The init function of the amplify filter.
 101  *
 102  * \param f Pointer to the struct to initialize.
 103  */
 104 void amp_filter_init(struct filter *f)
 105 {
 106         struct amp_filter_args_info dummy;
 107
 108         amp_cmdline_parser_init(&dummy);
 109         f->open = amp_open;
 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
 116         };
 117 }