Crash in MovieSceneAudioInstance.cpp

Development Programming & Scripting UI
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1

Hi.
I encountered a crash with the audio track editor in UE4.12 Preview 5.
If you drag and drop an audio file onto any sequence track a new audio track is created for it. Now every time you play the sequence it crashes in MovieSceneAudioInstance.cpp:230
You can try this in the UMG sequence editor. Its probably because the PlaybackContext of UMG doesn’t return a valid UWorld object.

2

I was mistaken. GetPlaybackContext isn’t implemented in the UMGSequencePlayer class and returns null

3

Thanks Matze, this will be fixed in the next 4.12 preview/release.

In MovieSceneAudioTrackInstance.cpp, Line 230, I replaced this

UAudioComponent* AudioComponent = FAudioDevice::CreateComponent(TempPlaybackAudioCue, Actor ? Actor->GetWorld() : Player.GetPlaybackContext()->GetWorld(), Actor, false, false);

with

UWorld* World = Actor ? Actor->GetWorld() : (Player.GetPlaybackContext() != nullptr) ? Player.GetPlaybackContext()->GetWorld() : nullptr;

It looks like the audio track relies on Actors and UWorld right now. We may have to revisit the implementation of this track. My change fixes the crash, and it also plays the sound in UMG. I have not tested it in-game though.

4

my pleasure.
I’m writing a plugin with its own sequence player and tracks right now. How stable is sequencer? are there still a lot of changes coming in the future?

5

Awesome. Then I’ll start developing the sequencer part of my plugin proper.
Thanks for the heads up.

6

4.12 will contain the bulk of the updates. We do not anticipate API changes after this release. We are considering to redesign time management (floats have not worked out very well for us), but we’re not sure yet if it’s worth the effort. Sequencer is quite stable now. There are only a couple more bugs that we know of, and most are functional problems, not crashes.

7

Oh, and as far as extensibility (especially with plug-ins) goes, we will probably make a pass on that this Summer.