Hello @jjok , provided that the composer is set in the track information, all should be fine. The only question for me is now how can I make sure that the meta information is indeed retrieved and put into the track structure. That I can only answer once I get modipy to work with my local flac collection; see related thread https://discourse.mopidy.com/t/problem-scanning-local-flac-files/.
Talking of threads, at the moment, as I am still learning about modipy, I assume that extension code such as core-listeners is executed in the core thread context, .e.g. the on_start method or all event handlers such as track_playback_started. To be on the safe side, I have the latter put the data into a thread-safe queue and consume it in a different thread.
That being said, the question is anyway to what extend multi-threading is real in a python programme; I have not much experience here either. I used to use QThreads for a while which has a very neat concept of thread affinity and thread-safe object passing between objects.
Cheers, peter.