4.13 UseAudioThread=true causes subtitles to not always display

I noticed that when building a project with the experimental parameter UseAudioThread=true (in BaseEngine.ini), subtitles that should be displayed from a Dialogue Wave don’t always appear along with their audio (which seems to play fine). What’s more, sometimes the subtitles appear midway through the audio clip, though they still end at the correct time. I noticed it happening when using Spawn Dialogue at Location in BP, though it may also happen elsewhere.

Relevant system info:

Windows 10 64 bit


AMD FX-8150

GTX 660Ti EVGA Superclocked


If that’s not enough information, I can try to provide more.

It appears that this behavior occurs regardless of UseAudioThread’s value and rather this is a bug in 4.13 in general.

Hey Guitar_Bro,

It seems you and another user could be experiencing a similar issue. Just for clarity and consistency here is the other post I am mentioning.

Much like in his post, could you provide me with some steps to reproduce this issue on my end? Having a way to reproduce this issue on my end would be beneficial to entering a clear and full bug report.

Let me know if you have further questions or need additional assistance.


Ah ha! That appears to be the same problem. Apparently a few of my dialogue clips overlapped slightly, so that would make sense. I managed to reproduce it in a new project but I can’t seem to attach it (even though it’s under 5.2mb). I took a screenshot of the script though:

In this case, “s1” is just a dialogue wave that’s longer than 3 seconds, so the next one is triggered before completion, causing the unpredictable behavior.

So I have been trying to get this issue to reproduce on my end, but I am having trouble replicating the set up. In order to share your test project with me, you can upload the zip file to a shareable google drive link and provide me with that link in your response.

I am at the point now where I can see the subtitle text for the first Dialog Wave being played, but the second one does not appear. This is the case no matter the priority of the Media Sound Waves, and with or without a delay. Is this the issue you are reporting?

Let me know if you have further questions or need additional assistance.


I don’t think that’s exactly my issue as it appears to sometimes briefly show the second subtitle before it goes away too early and sometimes it just appears to late, but shows up a second or two into the clip. Additionally, I’ve had a few instances where the first clip never showed any subtitles either.

It may be worth a mention that when running my example project, I had to do it quite a few times before I noticed it happen again.

Here’s a drive link to my example: subtitle_bug

Thanks for the project as I was able to reproduce the issue on my end. I have gone ahead and entered a bug report for this issue which you can track by following the link below.


I will say that I tested this project in our Main branch (4.14) and the issue did not appear there. So, it seems this has been resolved along the way and a fix does not need to be made for this particular issue. With that said, I entered the bug for tracking purposes and so you can verify the issue is fixed when 4.14 is released.

Thank you,

Great, thanks!

Still not fixed in 4.15. We are experiencing the exact same problem all the time.

This is marked as ‘Won’t Fix’ because this is due to sound priorities – you need to make sure the audio/dialogue is using the proper priority so that the dialogue they want to play is correct.

Thank you,


Could you please explain what “proper priority” is? We have them ramping up over the course of our dialogues and still have the issue. We also have the issue where even the first audios subtitle wont display.