Something else I'm hoping that you can look at sometime. Don't know if this is even within your power, but...

The player application spits out certain pieces of track metadata on the serial port like this each time a track is changed:


The player application also spits out play/pause state and current playback position when those change:



This is missing the following data that the Bluetooth wants in its queries for information:
- Total tracks in current playlist
- Album title
- Total time length of currently playing track

Is there any way to do a Hijack hack, so that when the track metadata appears on the serial port, you use Hijack to go fishing for that information and then append that information to the serial port in the same type of format? For example, you could output it right after the Artist or the Genre. My code currently monitors for all of those things and constantly logs them, then triggers to send that data up to the host stereo in the following situations:
- Play/pause state changes.
- Track current playback timestamp changes.
- Genre message is received (at which point it sends all of the track information up).

Though if your version of the code will not be monitoring the serial port at all and will instead be retrieving that information directly then I could understand why you might not want to waste the time on it. However there are some advantages to monitoring the serial port for this information... It means that you wouldn't have to do any detection logic to determine when any of that stuff changes and could just wait for the player application to tell you about it via the serial messages.