fade-in/fade-out effect on pause/unpause

[mokurin000]

This would make the sound more natural than suspend suddenly

Accordingly, we could implement ease-in-out as:

fade in: $\frac{1}{2}(1 - \cos(x\pi))$
fade out: $\frac{1}{2}(1 + \cos(x\pi))$

Which gives curve like:

Also, you may refer to wikipedia for detailed modern approach. cosine function is just the easiest to implement

[mokurin000]

Noticed S-Curve combines exponential curve to the midpoint, and logarithm curve for the other half,

I think $\large \dfrac{e^{2{c}x-{c}}}{4^{x}}$ can be the first half part, that will give an abrupt sound at the beginning, to make it prominent.

The remaining part can be cosine curve, or logarithm if we want more traditional effects

$\large \dfrac{1}{8} \ln \left( 2(e^{2} - e^{-2})x - e^{2} + 2 e^{-2} \right) + \dfrac{3}{4}$

more generally,

$\large \dfrac{1}{4k} \ln \left( 2(e^{k} - e^{-k}) x - e^{k} + 2 e^{-k} \right) + \dfrac{3}{4}$

Final effect

It can be optimized to be smoother by differentiate both function and make them equal at the midpoint, but I am too lazy to calculate

Comparison

[Konyaco]

This is unnecessary and brings extra complexity. There is no reason to say that pausing smoothly is better than pausing suddenly. Spotify does not use ease-in-out either. So, this should be an optional setting.

Currently I have no plans to implement this. If you can do it, I will be very appreciated.

[mokurin000]

Spotify does not use ease-in-out either. So, this should be an optional setting.

I think spotify has optional settings for crossfade¹, which will introduce even more complexity than fade-in/fade-out, the latter one only involving concurrent volume settings in background

Currently I have no plans to implement this. If you can do it, I will be very appreciated.

I will try to implement when I know kotlin well

Footnotes

1. https://support.spotify.com/us/article/tracks-transitions/ ↩

[mokurin000]

A similar, simpler and smooth function:

$\large \left(1 + e^{-m (x - 0.5)}\right)^{-1}$

It's very close to exponential-logarithm curve, while being smooth. and easier to calculate