When you use hotkeys to adjust the playback rate up or down, this setting determines
how much the rate will change each time you press the hotkey. Recommended value is either
0.125 or 0.25.
Note: the native video playback rate GUI controls in the bottom-right corner of videos
uses a step size of 0.25, so if your current speed happens to be a multiple of 0.25, then
the native GUI will show a checkmark next to your speed, which gives you an easy way to see
what the current speed actually is. But if you don't care about that,
then feel free to use any step size you like. Example:
