compress_filter.c

   1 /*
   2  * Copyright (C) 2005-2013 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file compress_filter.c Paraslash's dynamic audio range compressor. */
   8
   9 /*
  10  * Uses ideas of AudioCompress, (C) 2002-2004  M. Hari Nezumi <magenta@trikuare.cx>
  11  */
  12
  13 #include <regex.h>
  14
  15 #include "para.h"
  16 #include "compress_filter.cmdline.h"
  17 #include "list.h"
  18 #include "sched.h"
  19 #include "ggo.h"
  20 #include "buffer_tree.h"
  21 #include "filter.h"
  22 #include "string.h"
  23 #include "error.h"
  24
  25 /** Data specific to the compress filter. */
  26 struct private_compress_data {
  27         /** The current multiplier. */
  28         unsigned current_gain;
  29         /** Points to the configuration data for this instance of the compress filter. */
  30         struct compress_filter_args_info *conf;
  31         /** Maximal admissible gain. */
  32         unsigned max_gain;
  33         /** Number of samples already seen. */
  34         unsigned num_samples;
  35         /** Absolute value of the maximal sample in the current block. */
  36         int peak;
  37 };
  38
  39 static void compress_close(struct filter_node *fn)
  40 {
  41         free(fn->private_data);
  42 }
  43
  44 static int compress_post_select(__a_unused struct sched *s, struct task *t)
  45 {
  46         struct filter_node *fn = container_of(t, struct filter_node, task);
  47         struct private_compress_data *pcd = fn->private_data;
  48         struct btr_node *btrn = fn->btrn;
  49         bool inplace = btr_inplace_ok(btrn);
  50         int ret;
  51         char *inbuf;
  52         size_t length, i;
  53         int16_t *ip, *op;
  54         unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
  55                 mask = (1 << pcd->conf->blocksize_arg) - 1;
  56
  57         //inplace = false;
  58 next_buffer:
  59         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
  60         if (ret < 0)
  61                 goto err;
  62         if (ret == 0)
  63                 return 0;
  64         btr_merge(btrn, fn->min_iqs);
  65         length = btr_next_buffer(btrn, &inbuf) & ~(size_t)1;
  66         if (length == 0) { /* eof and 1 byte available */
  67                 ret = -E_COMPRESS_EOF;
  68                 goto err;
  69         }
  70         ip = (int16_t *)inbuf;
  71         if (inplace)
  72                 op = ip;
  73         else
  74                 op = para_malloc(length);
  75         for (i = 0; i < length / 2; i++) {
  76                 /* be careful in that heat, my dear */
  77                 int sample = *ip++, adjusted_sample = (PARA_ABS(sample) *
  78                         pcd->current_gain) >> gain_shift;
  79                 if (adjusted_sample > 32767) { /* clip */
  80                         PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
  81                                 sample, adjusted_sample);
  82                         adjusted_sample = 32767;
  83                         pcd->current_gain = (3 * pcd->current_gain +
  84                                 (1 << pcd->conf->inertia_arg)) / 4;
  85                         pcd->peak = 0;
  86                 } else
  87                         pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
  88                 op[i] = sample >= 0? adjusted_sample : -adjusted_sample;
  89                 if (++pcd->num_samples & mask)
  90                         continue;
  91 //              PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
  92 //                      pcd->peak);
  93                 if (pcd->peak < pcd->conf->target_level_arg) {
  94                         if (pcd->current_gain < pcd->max_gain)
  95                                 pcd->current_gain++;
  96                 } else
  97                         pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
  98                                 1U << pcd->conf->inertia_arg);
  99                 pcd->peak = 0;
 100         }
 101         if (inplace)
 102                 btr_pushdown_one(btrn);
 103         else {
 104                 btr_consume(btrn, length);
 105                 btr_add_output((char *)op, length, btrn);
 106         }
 107         goto next_buffer;
 108 err:
 109         assert(ret < 0);
 110         btr_remove_node(&fn->btrn);
 111         return ret;
 112 }
 113
 114 /** TODO: Add sanity checks */
 115 static int compress_parse_config(int argc, char **argv, void **config)
 116 {
 117         struct compress_filter_args_info *conf = para_calloc(sizeof(*conf));
 118
 119         compress_filter_cmdline_parser(argc, argv, conf);
 120         *config = conf;
 121         return 1;
 122 }
 123
 124 static void compress_open(struct filter_node *fn)
 125 {
 126         struct private_compress_data *pcd = para_calloc(
 127                 sizeof(struct private_compress_data));
 128         pcd->conf = fn->conf;
 129         fn->private_data = pcd;
 130         fn->min_iqs = 2; /* 16 bit audio */
 131         pcd->current_gain = 1 << pcd->conf->inertia_arg;
 132         pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
 133 }
 134
 135 static void compress_free_config(void *conf)
 136 {
 137         compress_filter_cmdline_parser_free(conf);
 138 }
 139
 140 /**
 141  * The init function of the compress filter.
 142  *
 143  * \param f Pointer to the struct to initialize.
 144  */
 145 void compress_filter_init(struct filter *f)
 146 {
 147         struct compress_filter_args_info dummy;
 148
 149         compress_filter_cmdline_parser_init(&dummy);
 150         f->open = compress_open;
 151         f->close = compress_close;
 152         f->pre_select = generic_filter_pre_select;
 153         f->new_post_select = compress_post_select;
 154         f->post_select = NULL;
 155         f->parse_config = compress_parse_config;
 156         f->free_config = compress_free_config;
 157         f->help = (struct ggo_help) {
 158                 .short_help = compress_filter_args_info_help,
 159                 .detailed_help = compress_filter_args_info_detailed_help
 160         };
 161 }