Canary, v1.0.0.5156, tested with mpsecurity and mptuner, onesync off and on
I expect to hear the radio upon returning
No radio is heard
Client, Radio
Requires two clients. Player 1 - In any vehicle with a radio Player 2 - On foot
Player 1 tunes to whichever radio station. Player 2 hears the radio.
Player 1 then drives >40.0 units but <424.0 (onesync on) / 900.0 (onesync off) away and returns back to Player 2. Player 2 does not hear the radio until Player 1 swaps radio station OR drives >424.0 (onesync on) or >900.0 (onesync off) and comes back again.
If Player 1 is less than 40.0 units away, which seems to be within the attenuation distance, the radio is heard continuously.
I had someone verify that this is not an issue on GTA:O.
After looking at this, here are some insights (1604 retail addresses):
At 0x1403D9F57 there is a some logic for recreating the radio emitter. In addition to some vehicle hardcodes 0x149BD32A (pbus2), 0xEDA4ED97 (blimp3), there is also a check for a specific flag: *(audEntity + 164) & 0x80) != 0 …
This value is set in: 0x1403D9C94 and 0x140F50284: which checks if the entity has a PLAYER_VEHICLE decor value (i.e., one that exists; value does not matter). There are likely some more features dependant on this decor that could probably be searched for.
Also, 0xC1805D05E6D4FE10, 0x2F7CEB6520288061, and 0xDA07819E452FFE8F are all natives related to radio emitters, its low-pass/distance threshold, etc.
(After a two minute search…) It seems PLAYER_VEHICLE has uses related to VEHICLE_LOD_MULTIPLIER, Is Stationary in CVehicleGameStateDataNode, and things in CVehicleTrailerAttachPoint and CVehicleGadgetTowArm.
PLAYER_BOSS and PLAYER_GOON are also referenced in a few places: e.g., CTaskEnterVehicle, CTaskPlayerOnFoot. CTaskOpenVehicleDoorFromOutside has also references to PLAYER_HACKER_TRUCK, PLAYER_AVENGER, and PLAYER_TRUCK.