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 void 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         t->error = 0;
  60         ret = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
  61         if (ret < 0)
  62                 goto err;
  63         if (ret == 0)
  64                 return;
  65         btr_merge(btrn, fn->min_iqs);
  66         length = btr_next_buffer(btrn, &inbuf) & ~(size_t)1;
  67         if (length == 0) { /* eof and 1 byte available */
  68                 ret = -E_COMPRESS_EOF;
  69                 goto err;
  70         }
  71         ip = (int16_t *)inbuf;
  72         if (inplace)
  73                 op = ip;
  74         else
  75                 op = para_malloc(length);
  76         for (i = 0; i < length / 2; i++) {
  77                 /* be careful in that heat, my dear */
  78                 int sample = *ip++, adjusted_sample;
  79
  80                 adjusted_sample = sample > 0? sample : -sample;
  81                 adjusted_sample *= pcd->current_gain;
  82                 adjusted_sample >>= gain_shift;
  83                 if (adjusted_sample > 32767) { /* clip */
  84                         adjusted_sample = 32767;
  85                         pcd->current_gain = (3 * pcd->current_gain +
  86                                 (1 << pcd->conf->inertia_arg)) / 4;
  87                         pcd->peak = 0;
  88                 } else if (adjusted_sample > pcd->peak)
  89                         pcd->peak = adjusted_sample;
  90                 op[i] = sample >= 0? adjusted_sample : -adjusted_sample;
  91                 if (++pcd->num_samples & mask)
  92                         continue;
  93 //              PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
  94 //                      pcd->peak);
  95                 if (pcd->peak < pcd->conf->target_level_arg) {
  96                         if (pcd->current_gain < pcd->max_gain)
  97                                 pcd->current_gain++;
  98                 } else
  99                         pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
 100                                 1U << pcd->conf->inertia_arg);
 101                 pcd->peak = 0;
 102         }
 103         if (inplace)
 104                 btr_pushdown_one(btrn);
 105         else {
 106                 btr_consume(btrn, length);
 107                 btr_add_output((char *)op, length, btrn);
 108         }
 109         goto next_buffer;
 110 err:
 111         assert(ret < 0);
 112         t->error = ret;
 113         btr_remove_node(&fn->btrn);
 114 }
 115
 116 /** TODO: Add sanity checks */
 117 static int compress_parse_config(int argc, char **argv, void **config)
 118 {
 119         struct compress_filter_args_info *conf = para_calloc(sizeof(*conf));
 120
 121         compress_filter_cmdline_parser(argc, argv, conf);
 122         *config = conf;
 123         return 1;
 124 }
 125
 126 static void compress_open(struct filter_node *fn)
 127 {
 128         struct private_compress_data *pcd = para_calloc(
 129                 sizeof(struct private_compress_data));
 130         pcd->conf = fn->conf;
 131         fn->private_data = pcd;
 132         fn->min_iqs = 2; /* 16 bit audio */
 133         pcd->current_gain = 1 << pcd->conf->inertia_arg;
 134         pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
 135 }
 136
 137 static void compress_free_config(void *conf)
 138 {
 139         compress_filter_cmdline_parser_free(conf);
 140 }
 141
 142 /**
 143  * The init function of the compress filter.
 144  *
 145  * \param f Pointer to the struct to initialize.
 146  */
 147 void compress_filter_init(struct filter *f)
 148 {
 149         struct compress_filter_args_info dummy;
 150
 151         compress_filter_cmdline_parser_init(&dummy);
 152         f->open = compress_open;
 153         f->close = compress_close;
 154         f->pre_select = generic_filter_pre_select;
 155         f->post_select = compress_post_select;
 156         f->parse_config = compress_parse_config;
 157         f->free_config = compress_free_config;
 158         f->help = (struct ggo_help) {
 159                 .short_help = compress_filter_args_info_help,
 160                 .detailed_help = compress_filter_args_info_detailed_help
 161         };
 162 }