Improved Sound Commands

Hopefully this is simple enough: What I'd like to see is new features and improvements to the current sound commands: /playsound and /stopsound. The goal behind this is to improve the mapmaker's toolkit by letting them be more dynamic with how they play and stop their sounds, and open new possibilities and customizations. The recent snapshots and new commands have been awesome to see, so hopefully we get to see improvements to other commands like this.

/playsound:

• Adding a command parameter where the sound can start at a certain sound timestamp, ideally done by milliseconds or game ticks.
• Adding command parameters that lets you decide the fade in, stay, and fade out times of a sound. This would include adding a fade in/out feature for sounds. The parameters are similar to that of how Titles/Subtitles work right now.

/stopsound:

• Adding a command parameter that lets you decide how long a sound will take to fade out. This is useful if you need to suddenly stop a sound, but don't want to do it sharply/immediately and want to add a better effect to it.

Possible uses:

• Properly trimming long sounds. For example, the Elytra flight sound sounds very good, but is a very long sound file. These commands would give mapmakers the ability to trim how long they want this sound to play.
• Custom Music System. With this system, it's much more feasible to add a good-quality music system, fit with fade-ins and fade-outs.