[amelius]

The only thing I want is to turn off sound from the start, in my browser at work.

(Unfortunately, the PulseAudio volume control doesn't show Chrome in its "applications" tab before it has played a sound.)

[cszerzo]

I don't know if that is possible, but you can mute individual web pages (seemingly based on domain name) and they will stay muted until you say otherwise. Works for me pretty well.

[iwalsh]

chrome://flags/#autoplay-policy