I am running LineageOS on a RaspberryPI for a car stereo head deck which is working extremely well.
I want to try to get bluetooth hands free working. I have enabled bluetooth settings which allow me to select the RaspberryPI as the playback device when making calls, but I dont get any audio from the call.
The audio works fine for everything else, just not bluetooth sink.
I have added the following to my build.prop
Can anyone tell me why it could be that I dont get any audio? Can I have A2DP SINK and SOURCE enabled at the same time?
In my build.prop
# Bluetooth
#bluetooth.device.class_of_device=90,2,12
#bluetooth.profile.a2dp.source.enabled=true
bluetooth.profile.asha.central.enabled=true
bluetooth.profile.avrcp.target.enabled=true
bluetooth.profile.bap.broadcast.assist.enabled=true
bluetooth.profile.bap.unicast.client.enabled=true
bluetooth.profile.bas.client.enabled=true
bluetooth.profile.ccp.server.enabled=true
bluetooth.profile.csip.set_coordinator.enabled=true
bluetooth.profile.gatt.enabled=true
bluetooth.profile.hap.client.enabled=true
bluetooth.profile.hfp.ag.enabled=true
bluetooth.profile.hid.device.enabled=true
bluetooth.profile.hid.host.enabled=true
bluetooth.profile.map.server.enabled=true
bluetooth.profile.mcp.server.enabled=true
bluetooth.profile.opp.enabled=true
bluetooth.profile.pan.nap.enabled=true
bluetooth.profile.pan.panu.enabled=true
bluetooth.profile.pbap.server.enabled=true
bluetooth.profile.sap.server.enabled=true
bluetooth.profile.vcp.controller.enabled=true
persist.bluetooth.a2dp_aac.vbr_supported=true
## new entries
bluetooth.device.class_of_device=38,4,8
bluetooth.profile.a2dp.sink.enabed=true
bluetooth.profile.avrcp.controller.enabled=true
bluetooth.profile.hfp.hf.enabled=true
bluetooth.profile.map.client.enaled=true
bluetooth.profile.pbap.client.enabled=true
bluetooth.gatt.check_encryped_link.enabled=false
Tried enabling bluetooth SINK and hoped for call audio to play via bluetooth device.
There is a simple technical explanation for your observation.
The Advanced Audio Distribution Profile (A2DP) only supports one-way audio. Telephony, on the other hand, always requires two-way audio. This is why Hands-Free Profile (HFP) and/or Headset Profile (HSP) are used.