I repeat my post already posted in the original thread now closed.
With AppInventor I created a streaming player application for my Radio (and TV).
I'm updating the application with new features and I wanted to replace the current notification code with this extension, which works fine, but doesn't communicate properly metadata (image, artist/title, lyrics...) to connected bluetooth devices (headphones, cars, etc. ..); and it doesn't even communicate commands from buttons.
The reason for the metadata is that live streaming doesn't have a fixed duration like a music file, and therefore you need to set this because android needs to know about it. Without this information, the notification system does not communicate metadata correctly with the device.
If you could fix this by inserting a block that allows you to specify the duration of the streamed content, (typically indeterminate live stream has duration -1 ) and thus fix the bug, I'd like to use that for my update.
p.s. Thanks to Patryk_F for the hint below; that is the extension that I am currently using, but that lacks some possibilities, some of which I have personally corrected by writing and rewriting part of the code (such as the update for Android 12+), others it is very complex because, given the structure, you would have to rewrite all the code.