FMOD Event callbacks not firing when Bus has 0 volume

[apfelbaum]

Hello, i encountered a bug when trying this here:

Mute FMOD sounds when UE4 is out of focus (alt+tab)

Hi there, I am having problems to mute all the FMOD sounds when the game is not on focus (when I press alt+tab). I know there is an Engine variable called “UnfocusedVolumeMultiplier” that I should put to 0.0, but this one does not work with FMOD sounds, can some one help me please? Thank you very much and I hope you have a nice day.

When my buses are set to 0 volume no single callback is fired for event instances.

For debugging i did this:

		MusicEventInstance.Instance->setCallback(MusicFinished, FMOD_STUDIO_EVENT_CALLBACK_ALL);

But i usually do this to track wether a song on my game stopped playing

MusicEventInstance.Instance->setCallback(MusicFinished, FMOD_STUDIO_EVENT_CALLBACK_CREATE_PROGRAMMER_SOUND | FMOD_STUDIO_EVENT_CALLBACK_DESTROYED);

Best regards

Ps. The EventInstance remains valid and also remains in state “FMOD_STUDIO_PLAYBACK_PLAYING” even though the event is clearly finished playing.

Perhaps it is interesting to note this is a Programmer Instrument

[cameron-fmod]

FMOD_STUDIO_EVENT_CALLBACK_DESTROYED is only called when the actual Event Instance is destroyed, otherwise FMOD_STUDIO_EVENT_CALLBACK_SOUND_STOPPED will tell you when the programmer sound stops.

I’m not able to reproduce this myself, it appears to be behaving as expected.
What versions of FMOD and Unreal are you using?

[apfelbaum]

Hi cameron,
I am encountering no single callback being called. I assume that using the flag

FMOD_STUDIO_EVENT_CALLBACK_ALL

to register to callbacks allows me to listen to all of them. But none of them is called for me.

I am using UE 5.5 and FMOD 2.03.05 EA

Also, when the callback should fire, I am tabbed out of the game to see wether the whole “muting while the game is not in focus” works (which it does).