I've been searching the internet for two days now and have made several attempts to use my Raspberry Pi (Computemodule 4) as a Bluetooth sink with AVRCP protocol. Unfortunately, I have come to no real result so far, because although many posts exist on this topic, they are either very old, do not fit my application purpose or did not work. Now I am looking in this forum for an answer to the following:
I have a USB speaker connected to my Raspberry Pi, on which I want to stream music from my phone/laptop. So I want to use my phone/laptop as a bluetooth source and the Raspberry as a bluetooth sink. My end goal is to be able to stream music while displaying the song title, image of the album cover, volume, etc. on a GUI which is running on my raspberry.
Unfortunately, so far I've only managed to stream music via bluetooth, but not from the Raspberry to make the music louder/quieter, display album cover/song title, etc. If I have informed myself correctly, what is running on it now is the "A2DP protocol" and what I want is the "AVRCP protocol". Apparently it should work (according to forums and ChatGPT), but so far I failed miserably, because the whole topic of Bluetooth in Linux is new territory for me and my programming skills are also not outstanding.
I tried several different Blog-posts/manuals how to setup a AVRCP-sink, but nothing worked. Can anyone give me some pointers on how to implement this? Maybe also share a blog article or similar which still works on a current Raspbian version? Thanks in advance for your help!