070e68c084
Makes more sense to have this be on the same level as the workspace since technically this crate can be used separately.
77 lines
2 KiB
Rust
77 lines
2 KiB
Rust
// nih-plug: plugins, but rewritten in Rust
|
|
// Copyright (C) 2022 Robbert van der Helm
|
|
//
|
|
// 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, either version 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// 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, see <https://www.gnu.org/licenses/>.
|
|
|
|
pub const MINUS_INFINITY_DB: f32 = -100.0;
|
|
|
|
/// Convert decibels to a voltage gain ratio, treating anything below -100 dB as minus infinity.
|
|
pub fn db_to_gain(dbs: f32) -> f32 {
|
|
if dbs > MINUS_INFINITY_DB {
|
|
10.0f32.powf(dbs * 0.05)
|
|
} else {
|
|
0.0
|
|
}
|
|
}
|
|
|
|
/// Convert a voltage gain ratio to decibels. Gain ratios that aren't positive will be treated as
|
|
/// [MINUS_INFINITY_DB].
|
|
pub fn gain_to_db(gain: f32) -> f32 {
|
|
if gain > 0.0 {
|
|
gain.log10() * 20.0
|
|
} else {
|
|
MINUS_INFINITY_DB
|
|
}
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn test_db_to_gain_positive() {
|
|
assert_eq!(db_to_gain(3.0), 1.4125376);
|
|
}
|
|
|
|
#[test]
|
|
fn test_db_to_gain_negative() {
|
|
assert_eq!(db_to_gain(-3.0), 1.4125376f32.recip());
|
|
}
|
|
|
|
#[test]
|
|
fn test_db_to_gain_minus_infinity() {
|
|
assert_eq!(db_to_gain(-100.0), 0.0);
|
|
}
|
|
|
|
#[test]
|
|
fn test_gain_to_db_positive() {
|
|
assert_eq!(gain_to_db(4.0), 12.041201);
|
|
}
|
|
|
|
#[test]
|
|
fn test_gain_to_db_negative() {
|
|
assert_eq!(gain_to_db(0.25), -12.041201);
|
|
}
|
|
|
|
#[test]
|
|
fn test_gain_to_db_minus_infinity_zero() {
|
|
assert_eq!(gain_to_db(0.0), MINUS_INFINITY_DB);
|
|
}
|
|
|
|
#[test]
|
|
fn test_gain_to_db_minus_infinity_negative() {
|
|
assert_eq!(gain_to_db(-2.0), MINUS_INFINITY_DB);
|
|
}
|
|
}
|