IOS/ iPhone bluetooth (a2dp, avrc, avct, ...) volume control not working?

[avanderheijden]

Hi guys,

I was playing with the a2dp_sink example to stream audio from an IOS device to esp. Streaming works fine (yay), but volume control does not, at least from my iPhone (IOS 11.4). When I change the volume using the hw buttons there is also no event triggered, at least I don't see it. When going all the way down to muted volume level, the audio is indeed muted. But this is because the phone sends just samples of 0.

I was playing with bluetooth audio before on linux and remember that volume changes can be over a2dp, avrc, avct, but I don't remember how it is implemented in iPhone. I played around with all the bluedroid stack files to see if I can somewhere catch a volume change event, but no luck.

Who has solved this already, or could point me in the direction how to capture volume change events?

Thanks!

[avanderheijden]

Update:
iPhone controls volume over AVRC. Reading the API documentation I saw that AVRC target is not yet implemented, only controller role. So that's why I don't see any events happening.

Any idea when AVRC target will be implemented?

[zeitounian]

Good night, your work was very good, I need help to connect the Iphone to the ESP32, I do not succeed in my attempts, how do I run the devices, how do I pair with Android.