Please cap how loud sounds can be

[melody-rs]

messing around with volume calculations shouldn't hurt my ears this much

https://github.com/user-attachments/assets/f6619396-c245-4efa-9cf3-627c850a7556

[tesselode]

Can you show what the code is that caused this?

It's important that sounds can be played with positive gain, since some sounds are quiet and need to be louder, but I agree that what you posted here is not a desirable result.

[melody-rs]

I was trying to replicate the code from https://github.com/mkxp-z/mkxp-z/pull/208/files#diff-3216992fdc41349399a23a9468d6e272ba8382e89f63d2beebd0d477b468372eR174-R200 and wrote this function to convert RPG Maker's 0-100 volume scale to kira::Decibels

    fn volume_to_db(&self) -> kira::Decibels {
        let amplitude = self.volume.map(|v| v as f32 / 100.0).unwrap_or(1.0);
        10.0_f2.powf(-(34.0 / 20.0) * (1.0 - amplitude) * 100.0).into()
    }

I realized I needed to use the inverse to actually do this properly, so I used amplitude.log10() * 4.0 / 7.0 + 1.0 instead. It's still too loud though and changing the amplitude has a minimal effect on the volume

[Roms1383]

Not sure if my test is relevant / my code exempt of bug, but here's what I noticed lately when increasing volume above amplitude 1.0 (single streaming sound playing).

See it on Youtube (file too big to be uploaded here).

[tesselode]

@melody-rs I don't think your code is right for converting amplitude to decibels. Here's my test code using your equation:

fn main() -> Result<(), Box<dyn Error>> {
	for i in (0..=100).step_by(10) {
		let volume = i as f32;
		println!("{} -> {:?}", volume, volume_to_db(volume));
	}

	Ok(())
}

fn volume_to_db(volume: f32) -> kira::Decibels {
	let amplitude = volume / 100.0;
	(amplitude.log10() * 4.0 / 7.0 + 1.0).into()
}

And here's the result I get:

0 -> Decibels(-inf)
10 -> Decibels(0.4285714)
20 -> Decibels(0.60058856)
30 -> Decibels(0.70121217)
40 -> Decibels(0.7726057)
50 -> Decibels(0.82798284)
60 -> Decibels(0.87322927)
70 -> Decibels(0.9114846)
80 -> Decibels(0.9446229)
90 -> Decibels(0.9738529)
100 -> Decibels(1.0)

As you go from an RPG Maker volume of 0-100, decibels should go from Decibels::SILENCE (-60dB) to Decibels::IDENTITY (0dB).

This site lists the correct conversion from amplitude to decibels:

dB = 20 * log10(amplitude)

This is for a 0.0-1.0 amplitude, so you should scale it beforehand for 0-100.

If you just want a perceptually linear ramp from silence to full volume, just do a linear interpolation from -60dB to 0dB with a factor of volume / 100.

[tesselode]

@Roms1383 if you play a sound too loud, it's going to get crunchy. That's just how digital audio works.

[Roms1383]

@tesselode thanks for your reply, it makes perfect sense as far as I'm concerned. the feeling that louder sounds had a better outcome in prior versions might utterly be a false memory of mine.