Question

I’m writing a C# wrapper around libspotfiy, and have a problem with the track playing. From what I can tell, when I want to start streaming a track for the first time in a session, I should call

sp_session_player_load(sessionHandle, trackHandle)
sp_session_player_play(sessionHandle, true);

This is what I’m doing, and it works fine. The problem start when I want to play something else. With a track still playing, what am I meant to do to play a new one? Should I call

sp_session_player_play(sessionHandle, false);
sp_session_player_unload(sessionHandle);

Before then calling a new round of load/play? I ask because when I do this, I often see my program hang when I call the unload, or call play with an argument of false. I’m using the get_audio_buffer_stats callback. I’ve got appropriate thread syncronisation in place, so I’m wondering if I’mu sing the api incorrectly?

Answer 1

This is exactly what the official Mac and iOS library does, and it works fine:

When playing for the first time:

sp_session_player_load(sessionHandle, trackHandle)
sp_session_player_play(sessionHandle, true);

When playing again:

sp_session_player_play(sessionHandle, false);
sp_session_player_unload(sessionHandle);
sp_session_player_load(sessionHandle, trackHandle)
sp_session_player_play(sessionHandle, true);

There are a couple of things you can check, though:

• The most common hang I’ve seen is due to how the program implements the notify_main_thread callback. When you get this, you must schedule a call so sp_session_process_events on the main thread in a non-blocking way. I.e., your notify_main_thread implementation should return before sp_session_process_events is called on the other thread.

• Try taking out your get_audio_buffer_stats implementation. This Mac/iOS library doesn’t implement this at all – it isn’t required.

If this isn’t enough, please try to get a stack trace of the hang. If you catch it in the debugger, hitting pause is often good enough.