amp_filter.c

   1 /*
   2  * Copyright (C) 2009 Andre Noll <maan@tuebingen.mpg.de>
   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 #include <lopsub.h>
  11
  12 #include "filter_cmd.lsg.h"
  13 #include "para.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "buffer_tree.h"
  17 #include "filter.h"
  18 #include "string.h"
  19 #include "error.h"
  20
  21 extern char *stat_item_values[NUM_STAT_ITEMS];
  22
  23 /** Data specific to the amplify filter. */
  24 struct private_amp_data {
  25         /** Amplification factor. */
  26         unsigned amp;
  27 };
  28
  29 static void amp_close(struct filter_node *fn)
  30 {
  31         free(fn->private_data);
  32 }
  33
  34 static void amp_open(struct filter_node *fn)
  35 {
  36         struct private_amp_data *pad = para_calloc(sizeof(*pad));
  37         unsigned given = FILTER_CMD_OPT_GIVEN(AMP, AMP, fn->lpr);
  38         uint32_t amp_arg = FILTER_CMD_OPT_UINT32_VAL(AMP, AMP, fn->lpr);
  39
  40         fn->private_data = pad;
  41         fn->min_iqs = 2;
  42         if (!given && stat_item_values[SI_amplification])
  43                 sscanf(stat_item_values[SI_amplification], "%u", &pad->amp);
  44         else
  45                 pad->amp = amp_arg;
  46         PARA_INFO_LOG("amplification: %u (scaling factor: %1.2f)\n",
  47                 pad->amp, pad->amp / 64.0 + 1.0);
  48 }
  49
  50 static int amp_post_select(__a_unused struct sched *s, void *context)
  51 {
  52         struct filter_node *fn = context;
  53         struct private_amp_data *pad = fn->private_data;
  54         struct btr_node *btrn = fn->btrn;
  55         int ret, factor = 64 + pad->amp;
  56         size_t i, in_bytes, len;
  57         int16_t *in, *out;
  58         bool inplace = btr_inplace_ok(btrn);
  59
  60         if (pad->amp == 0) { /* no amplification */
  61                 btr_splice_out_node(&fn->btrn);
  62                 return -E_AMP_ZERO_AMP;
  63         }
  64 next_buffer:
  65         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
  66         if (ret < 0)
  67                 goto err;
  68         if (ret == 0)
  69                 return 0;
  70         btr_merge(btrn, fn->min_iqs);
  71         in_bytes = btr_next_buffer(btrn, (char **)&in);
  72         len = in_bytes / 2;
  73         if (len == 0) { /* eof and in_bytes == 1 */
  74                 ret = -E_AMP_EOF;
  75                 goto err;
  76         }
  77
  78         if (inplace)
  79                 out = in;
  80         else
  81                 out = para_malloc(len * 2);
  82
  83         for (i = 0; i < len; i++) {
  84                 int x = (in[i] * factor) >> 6;
  85
  86                 out[i] = x;
  87                 if (out[i] != x) /* overflow, clip */
  88                         out[i] = (x >= 0)? 32767 : -32768;
  89         }
  90
  91         if (inplace)
  92                 btr_pushdown_one(btrn);
  93         else {
  94                 btr_consume(btrn, len * 2);
  95                 btr_add_output((char *)out, len * 2, btrn);
  96         }
  97         goto next_buffer;
  98 err:
  99         assert(ret < 0);
 100         btr_remove_node(&fn->btrn);
 101         return ret;
 102 }
 103
 104 const struct filter lsg_filter_cmd_com_amp_user_data = {
 105         .open = amp_open,
 106         .close = amp_close,
 107         .pre_select = generic_filter_pre_select,
 108         .post_select = amp_post_select,
 109 };