Code doesn't allow mixing of "services" in the same box, but IIRC the box can have a divider so long as each service remains on its respective side. The idea is the divider makes each side its own "box" for the purpose of splicing or terminating. The sides cannot share a common cable entry or exit, I think.
Not sure of the current Code as my book is from a previous decade... but Chapter 3 is Wiring Methods & Materials, Articles 312 and 314 cover meter bases to junction boxes. I think what you're looking for is in there.
It's not hum that will shut down the show. It's the one in a million chance that a real inspector see's the box and tells you to remove it. Or maybe the slight chance of fire or electrocution. This is the very reason you'll be very hard pressed to find an outlet cover that supports both A/C and low voltage audio or video signals. Not allowed in this state under any circumstance.