Audio recording from BT device (car radio/head unit) can cause automatic phone calls?

Question

In the latest update (which was recently) for one of my app (a video recorder) for Android smartphones I have added an option to record audio from a connected BT device. It can be done with the following function:

AudioManager.startBluetoothSco()

Today I have received the following review from one of my users:

I start the app and recording and it starts making phone calls on my cars Bluetooth radio

The user's device is Samsung Galaxy S23 Ultra on Android 14 (from Goolge Play Console) which he connects to his car radio I believe while he's driving his car

Can it be related? And why does it happen? My app doesn't have any code to make phone calls, only AudioManager.startBluetoothSco()/AudioManager.stopBluetoothSco() was added in the latest update when I start/stop recording with MediaRecorder

Answer 1

Yeah, this is definitely caused by AudioManager.startBluetoothSco() when a smartphone is connected to a Car Radio (Head Unit) by Bluetooth.

Insane... I hate some Google's Android's developers.

Another review from one of my users when this option is enabled:

If enabled, then my Head Unit constantly emulates a call to number 100000 from the dialer built into the Head Unit. At the same time, through the “phone” shortcut from the main Android Auto screen in the Head Unit, you can normally make and receive calls from the phone book. But the music no longer plays, since that pseudo-call is supposedly going on. Samsung A52s + Mitsubishi Outlander III (2021)

p.s.: When you are using this option on a smartphone which is connected to just some BT Headset then it works fine and audio is being recorded normally from this BT device instead of phone's built-in mic