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/* -*- Mode: C ; c-basic-offset: 2 -*- */
/*****************************************************************************
*
* This file is part of jack_mixer
*
* Copyright (C) 2006 Nedko Arnaudov <nedko@arnaudov.name>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
*****************************************************************************/
#include <stddef.h>
#include <stdbool.h>
#include <stdlib.h>
#include <math.h>
#include <assert.h>
#include "jack_mixer.h"
//#define LOG_LEVEL LOG_LEVEL_DEBUG
#include "log.h"
#include "list.h"
struct threshold
{
struct list_head scale_siblings;
double db;
double scale;
double a;
double b;
};
struct scale
{
struct list_head thresholds;
double max_db;
};
jack_mixer_scale_t
scale_create()
{
struct scale * scale_ptr;
scale_ptr = malloc(sizeof(struct scale));
if (scale_ptr == NULL)
{
return NULL;
}
INIT_LIST_HEAD(&scale_ptr->thresholds);
scale_ptr->max_db = -INFINITY;
LOG_DEBUG("Scale %p created", scale_ptr);
return (jack_mixer_scale_t)scale_ptr;
}
#define scale_ptr ((struct scale *)scale)
void
scale_destroy(
jack_mixer_scale_t scale)
{
free(scale_ptr);
}
bool
scale_add_threshold(
jack_mixer_scale_t scale,
float db,
float scale_value)
{
struct threshold * threshold_ptr;
LOG_DEBUG("Adding threshold (%f dBFS -> %f) to scale %p", db, scale, scale_ptr);
LOG_DEBUG("Threshold %p created ", threshold_ptr, db, scale);
threshold_ptr = malloc(sizeof(struct threshold));
if (threshold_ptr == NULL)
{
return false;
}
threshold_ptr->db = db;
threshold_ptr->scale = scale_value;
list_add_tail(&threshold_ptr->scale_siblings, &scale_ptr->thresholds);
if (db > scale_ptr->max_db)
{
scale_ptr->max_db = db;
}
return true;
}
#undef threshold_ptr
void
scale_calculate_coefficients(
jack_mixer_scale_t scale)
{
struct threshold * threshold_ptr;
struct threshold * prev_ptr;
struct list_head * node_ptr;
prev_ptr = NULL;
list_for_each(node_ptr, &scale_ptr->thresholds)
{
threshold_ptr = list_entry(node_ptr, struct threshold, scale_siblings);
LOG_DEBUG("Calculating coefficients for threshold %p", threshold_ptr);
if (prev_ptr != NULL)
{
threshold_ptr->a = (prev_ptr->scale - threshold_ptr->scale) / (prev_ptr->db - threshold_ptr->db);
threshold_ptr->b = threshold_ptr->scale - threshold_ptr->a * threshold_ptr->db;
LOG_DEBUG("%.0f dB - %.0f dB: scale = %f * dB + %f", prev_ptr->db, threshold_ptr->db, threshold_ptr->a, threshold_ptr->b);
}
prev_ptr = threshold_ptr;
}
}
/* Convert dBFS value to number in range 0.0-1.0 */
double
scale_db_to_scale(
jack_mixer_scale_t scale,
double db)
{
struct threshold * threshold_ptr;
struct threshold * prev_ptr;
struct list_head * node_ptr;
prev_ptr = NULL;
list_for_each(node_ptr, &scale_ptr->thresholds)
{
threshold_ptr = list_entry(node_ptr, struct threshold, scale_siblings);
if (db < threshold_ptr->db)
{
LOG_DEBUG("Match at %f dB treshold", threshold_ptr->db);
if (prev_ptr == NULL)
{
return 0.0;
}
return threshold_ptr->a * db + threshold_ptr->b;
}
prev_ptr = threshold_ptr;
}
return 1.0;
}
/* Convert number in range 0.0-1.0 to dBFS value */
double
scale_scale_to_db(
jack_mixer_scale_t scale,
double scale_value)
{
struct threshold * threshold_ptr;
struct threshold * prev_ptr;
struct list_head * node_ptr;
prev_ptr = NULL;
list_for_each(node_ptr, &scale_ptr->thresholds)
{
threshold_ptr = list_entry(node_ptr, struct threshold, scale_siblings);
if (scale_value <= threshold_ptr->scale)
{
if (prev_ptr == NULL)
{
return -INFINITY;
}
return (scale_value - threshold_ptr->b) / threshold_ptr->a;
}
prev_ptr = threshold_ptr;
}
return scale_ptr->max_db;
}
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