void* cls;
void* (*audio_init)(void *cls, int bits, int channels, int samplerate);
void (*audio_set_volume)(void *cls, void *session, float volume);
+ void (*audio_set_metadata)(void *cls, void *session, const void *buffer, int buflen);
+ void (*audio_set_coverart)(void *cls, void *session, const void *buffer, int buflen);
void (*audio_process)(void *cls, void *session, const void *buffer, int buflen);
void (*audio_flush)(void *cls, void *session);
void (*audio_destroy)(void *cls, void *session);