FMOD Delete channels after song is ended

FMOD Studio
1

So, basically, I created a tool that helps me place notes in songs for my game. When the song ends, FMOD deletes all its channels, and now I can’t scroll the song up/down, pause it, etc. I don’t have access to the FMOD Studio project—it’s on another person’s computer.

When I check the profiler, it’s clear that the channels are being deleted.

Right before song end

NVIDIA_Overlay_kgDk6qTBNj
NVIDIA_Overlay_kgDk6qTBNj1457×359 17.7 KB

After song ended

FMOD_Profiler_L3QEinEWK4
FMOD_Profiler_L3QEinEWK41055×319 13.7 KB

Only the channel groups remain. What should I do? Is this happening because of the FMOD Studio setup or my code?

2

Hi,

An option may be FMOD Engine | Studio API Reference - Studio:: Bus::lockChannelGroup which forces the FMOD system to keep a channel group avilable till Studio:: Bus::unlockChannelGroup is called.

Hope this helps!

3

I tried to lock channel groups, but it seems I’m targeting the wrong bus. Here’s what I did:

FMOD::Studio::Bus* bus = nullptr;
ERRCHECK(fmodSys->getBus("bus:/", &bus));

if (bus)
	ERRCHECK(bus->lockChannelGroup());

But it doesn’t work. I wanted to lock the channel group for the main bus, but the API doesn’t provide a direct way to get the correct bus. Is there another approach?

4

What are the errors that you are seeing? Would it be possible to share more code? Are you able to reproduce the issue in one of our example scripts: "C:\Program Files (x86)\FMOD SoundSystem\FMOD Studio API Windows\api\studio\examples\vs2019\examples.sln"

You’re current method is correct for locking the master bus, if you call fmodSys->flushCommands() after locking the bus, it will ensure the channel group is created in the next update call.

If you want to lock all the buses you could use:

FMOD::Studio::Bus* bus[256];
int busCount;
masterBank->getBusList(bus, 256, &busCount);
for (int BusIdx = 0; BusIdx < busCount; ++BusIdx)
{
    bus[BusIdx]->lockChannelGroup();
    fmodSys->flushCommands();
}

Hope this helps!

5

My code for creating and starting event is

FMOD::Studio::EventDescription* envDesc = nullptr;
std::string event = "event:/" + eventName;

ERRCHECK(fmodSys->getEvent(event.c_str(), &envDesc));

if (envDesc)
{
	FMOD::Studio::EventInstance* eventInstance = nullptr;

	ERRCHECK(envDesc->createInstance(&eventInstance));
	ERRCHECK(eventInstance->setCallback(nullptr));

	ERRCHECK(eventInstance->start());

	m_PauseVector.push_back(eventInstance);

	ResourceManager::LoadEventInstance(eventName, eventInstance);
}

Update

if (!m_PauseVector.empty())
{
	FMOD::Studio::EventInstance* instance = m_PauseVector.back();
	FMOD::Studio::EventDescription* envDesc = nullptr;

	if (instance->getDescription(&envDesc) == FMOD_OK && envDesc)
	{
		FMOD_STUDIO_LOADING_STATE state = FMOD_STUDIO_LOADING_STATE_ERROR;

		if (envDesc->getSampleLoadingState(&state) == FMOD_OK &&
			state == FMOD_STUDIO_LOADING_STATE_LOADED)
		{
			Audio::SetPosition(realName, 0);
			Audio::Pause(realName, true);

			m_PauseVector.pop_back();

		}
	}
}

So when i write

FMOD::Studio::Bus* bus = nullptr;
ERRCHECK(fmodSys->getBus("bus:/", &bus));

if (bus)
	ERRCHECK(bus->lockChannelGroup());

This code executes after the event is created but before it’s added to ResourceManager and m_PauseVector. The bus pointer is returned without errors, but the channel group remains unlocked - after playback ends, the channels still get deleted.

1 Like
6

Thank you for the code and testing that. Maybe we could look into a different solution. Could you explain the desired behavior? What are you hoping to do with the channels once the event has finished playing? The more information the better. Thanks