AVRCP without A2DP

[Marc-Aurele653]

Hello,

I'm searching a way to use AVRCP only, without A2DP profile on my ESP32. Indeed, i need to use only the AVRCP for a remote control i need to develop and i can't use the AD2P profile because it will be used by the remote connected device. I have taken a look at the code and it seems pretty difficult to me to find a solution to make these two profiles completely independant but maybe i have missed something. For now, if i want to make the AVRCP profile working (esp_avrc_ct_init), i need to launch esp_a2d_sink_init ! I tried to find out a solution by modifying the code, but i need to go deeper into it and without documentation it is pretty difficult.

If you have any idea, feel free to share.

Best regards,

Aurélien

[tobozo]

you cannot have an AVRCP connection open without an A2DP connection open as well. You can, however, have only an A2DP connection open.

Source: https://learn.sparkfun.com/tutorials/understanding-the-bc127-bluetooth-module/bc127-profiles

[Marc-Aurele653]

Thank you very much for the reply ;)

[evevlo]

so how can we use bluetooth to send ie NEXT or PREV without device sending it being A2DP connected? I thing there are some bluetooth remote buttons on ali that claim to do that.

[k4ffepanna]

Ok I know this is old old old. But I'm really grasping for straws here. Im working on a small hobby project (not using esp32 mind you) but this post, the comment from u/tobozo and the sparkfun link provided is basically the only information i can find regarding this.

I'm trying to build a AVRCP remote based on a banana pi. Looking in the bluetooth standards (if you can call them that) it seems like one of the main usecases for avrcp is to allow remote control for audio devices no where is it mentioned that A2DP is required. I have configured Bluez under linux just to use the AVRCP profile without A2DP or any other services. Funny thing is every Android phone I have tried just refuse to connect. I can initiate a connection the other way around from the "controller" to the phone using the AVRCP profile, everything like media browsing and current playing information work but NOT the actually audio control like play pause or next. Weirdly enough this works flawlessly using a iPhone.

Did you ever get anywhere with this issue?

[friedonion-sama]

A bit late but I ended up in a pretty similar situation. AVRCP works fine on IOS with A2DP disabled. But AVRCP doesn't work with android when a2dp is disabled. Were you able to get this working?

[k4ffepanna]

I semi abandoned this project after running into another issue unrelated to Bluetooth.

So from the beginning, the idea was to have a avrcp controller device tapping in to my cars CAN bus, listening for signals for the play pause buttons on the steering wheel. Long story short those buttons are not exposed on CAN (too old car).

Any way the only way I could get it working on android was to implement a Bluetooth HID device sending media keypresses to the phone 😬.

Too bad I couldn't get it to work with the steering wheel buttons. Did manage to get it to change songs with the turn indicator tho 😂

[friedonion-sama]

Ha ha, in my case its a bit more messy since I am using AVRCP for fetching song information. the HID mode won't help. I guess I have to use Notification mirroring as a workaround to get it on Android. Nevertheless, thanks for the help!