Feature Request: Map physical phone buttons to volume levels

[mihaelmilea]

On Oneplus 5T there is a three-state slider that mutes the general sound on its upper position and unmutes it on the middle or bottom position of the slider. Could that slider be used so that in the middle position the multimedia volume would be muted? - more exactly, the multimedia would be muted on the upper and middle position and unmuted on the bottom position. I tried to make a script to do that but I don't know how to control the volume of multimedia from command line. Thank you!