What does this means? Starvation in wasapi buffer

[Koca]

I get this every time i push play. I am specifically speaking about the first line that says :

Starvation detected in wasapi output buffer

Thank you

[cameron-fmod]

Warnings when building project with UE 4.13 and 1.08.11

Starvation detected in WASAPI output buffer - This means that the mixer was too slow to output sound briefly. If you are running the UE4 editor it isn’t a big deal since it might well occur if the editor is loading something or exporting, which might cause a CPU spike. If you see it in a real game, then it means that the mixer graph is too heavy and the sound may drop out. The missing DSP plugin message usually means that the plugin hasn’t been loaded, but again in the editor it is something …

[Koca]

Thank you,

Do you think that having 4 with Scatterer instruments ( each having a nested event in the playlist with a multi instrument ), a stereo track and a 6 channel track all in a single ambiance event can cause this warning to “preload sample data to avoid delay”? Is there are limit to how much instruments should be in one event? And btw the tracks are 3 minutes long…

Thank you

[Koca]

Also another question, what do you mean by “mixer graph is too heavy”?

I now tried on empty map, with “Load all banks” and “Sample data” turned off and there was no Starvation warning. I than loaded one ambience bank and played just one 2d ambience event with 6 channel loop of 15secs and i got the warning again. My mixer routing looks like this and there is only one multiband EQ on Ambience Grp. So what could have made it heavy? Oh and i turned off live update in UE4

Thanks

[cameron-fmod]

Is this in a built game or in the UE4 editor?

[Koca]

In the editor, i know that you wrote that it isn`t a big deal so i will try it in game asap.
But i made these tests in editor and it does seem to affect the results, even in the editor.

[Huangminfei]

I also encountered this situation.And I want to know what the mean of mixer graph is too heavy.Thanks.

[jeff_fmod]

I believe this is a reference to the internal dsp architecture inside the core API, which is a directed graph processing tree. There is an upper limit to how much processing can be performed in a single frame, and at that upper limit there is a lot of processing nodes in the graph, thus making the mixer graph “heavy”. More information on the DSP Engine Architecture can be found here https://fmod.com/resources/documentation-api?version=2.02&page=core-guide.html#dsp-engine-flexible-programmable-soft-synth-architecture

If you are experiencing this issue you may need to performance tune your audio usage.
Starting many events at the same time and utilising lots of expensive DSP effects can cause this problem, so reducing the amount of events being played at once and using buses for your expensive DSP effects can be good ways to optimise your FMOD Studio project.