compress_filter.c

   1 /*
   2  * Copyright (C) 2005-2009 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 #include <stdbool.h>
  15
  16 #include "para.h"
  17 #include "compress_filter.cmdline.h"
  18 #include "list.h"
  19 #include "sched.h"
  20 #include "ggo.h"
  21 #include "buffer_tree.h"
  22 #include "filter.h"
  23 #include "string.h"
  24 #include "error.h"
  25
  26 /** The size of the output data buffer. */
  27 #define COMPRESS_CHUNK_SIZE 40960
  28
  29 /** Data specific to the compress filter. */
  30 struct private_compress_data {
  31         /** The current multiplier. */
  32         unsigned current_gain;
  33         /** Points to the configuration data for this instance of the compress filter. */
  34         struct compress_filter_args_info *conf;
  35         /** Maximal admissible gain. */
  36         unsigned max_gain;
  37         /** Number of samples already seen. */
  38         unsigned num_samples;
  39         /** Absolute value of the maximal sample in the current block. */
  40         int peak;
  41 };
  42
  43 static ssize_t compress(char *inbuf, size_t inbuf_len, struct filter_node *fn)
  44 {
  45         size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
  46                 (fn->bufsize - fn->loaded) / 2 * 2);
  47         struct private_compress_data *pcd = fn->private_data;
  48         int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
  49         unsigned gain_shift = pcd->conf->inertia_arg + pcd->conf->damp_arg,
  50                 mask = (1 << pcd->conf->blocksize_arg) - 1;
  51
  52         if (!length)
  53                 return 0;
  54         for (i = 0; i < length / 2; i++) {
  55                 /* be careful in that heat, my dear */
  56                 int sample = *ip++, adjusted_sample = (PARA_ABS(sample) *
  57                         pcd->current_gain) >> gain_shift;
  58                 if (adjusted_sample > 32767) { /* clip */
  59                         PARA_NOTICE_LOG("clip: sample: %d, adjusted sample: %d\n",
  60                                 sample, adjusted_sample);
  61                         adjusted_sample = 32767;
  62                         pcd->current_gain = (3 * pcd->current_gain +
  63                                 (1 << pcd->conf->inertia_arg)) / 4;
  64                         pcd->peak = 0;
  65                 } else
  66                         pcd->peak = PARA_MAX(pcd->peak, adjusted_sample);
  67                 *op++ = sample >= 0? adjusted_sample : -adjusted_sample;
  68                 if (++pcd->num_samples & mask)
  69                         continue;
  70 //              PARA_DEBUG_LOG("gain: %u, peak: %u\n", pcd->current_gain,
  71 //                      pcd->peak);
  72                 if (pcd->peak < pcd->conf->target_level_arg) {
  73                         if (pcd->current_gain < pcd->max_gain)
  74                                 pcd->current_gain++;
  75                 } else
  76                         pcd->current_gain = PARA_MAX(pcd->current_gain - 2,
  77                                 1U << pcd->conf->inertia_arg);
  78                 pcd->peak = 0;
  79         }
  80         fn->loaded += length;
  81         return length;
  82 }
  83
  84 static void close_compress(struct filter_node *fn)
  85 {
  86         free(fn->private_data);
  87         free(fn->buf);
  88 }
  89
  90 /** TODO: Add sanity checks */
  91 static int compress_parse_config(int argc, char **argv, void **config)
  92 {
  93         int ret;
  94         struct compress_filter_args_info *compress_conf
  95                 = para_calloc(sizeof(*compress_conf));
  96
  97         ret = -E_COMPRESS_SYNTAX;
  98         if (compress_cmdline_parser(argc, argv, compress_conf))
  99                 goto err;
 100         *config = compress_conf;
 101         return 1;
 102 err:
 103         free(compress_conf);
 104         return  ret;
 105 }
 106
 107 static void open_compress(struct filter_node *fn)
 108 {
 109         struct private_compress_data *pcd = para_calloc(
 110                 sizeof(struct private_compress_data));
 111         pcd->conf = fn->conf;
 112         fn->private_data = pcd;
 113         fn->bufsize = COMPRESS_CHUNK_SIZE;
 114         fn->buf = para_malloc(fn->bufsize);
 115         pcd->current_gain = 1 << pcd->conf->inertia_arg;
 116         pcd->max_gain = 1 << (pcd->conf->inertia_arg + pcd->conf->aggressiveness_arg);
 117 }
 118
 119 /**
 120  * The init function of the compress filter.
 121  *
 122  * \param f Pointer to the struct to initialize.
 123  */
 124 void compress_filter_init(struct filter *f)
 125 {
 126         struct compress_filter_args_info dummy;
 127
 128         compress_cmdline_parser_init(&dummy);
 129         f->open = open_compress;
 130         f->close = close_compress;
 131         f->convert = compress;
 132         f->parse_config = compress_parse_config;
 133         f->help = (struct ggo_help) {
 134                 .short_help = compress_filter_args_info_help,
 135                 .detailed_help = compress_filter_args_info_detailed_help
 136         };
 137 }