Forum Discussion
Audio Desync / Loading
Hello!
When creating a course in Storyline 360, I use a lot of audio. Be it from recordings from an actual narrator, or the AI created voice. I have a timeline of audio that can range anywhere from 15 seconds to two minutes, and depending on the length, or how much time I need between statements to animate or trigger something, the slide may have 1 or several audio clips spaced out on the timeline. In other situations, the audio is set to trigger on a button press, and so there could be several clips stacked up and ready to go when the learner presses the button.
What I have experienced, and what others testing for me have experienced, is that some slides will start playing, but the audio takes a second to kick in, and now the first clip is delayed, so the timing with the animations is off, but now also it's delayed enough so it overlaps the start of the next clip.
I've never seen this in the preview, on Review 360, only in a published SCORM on two different LMS platforms.
My question is, how does Storyline/SCORM buffer this audio? Is it loading it all at once before the slide starts? Is it loading each clip as they appear on the timeline? Because I have noticed that for videos, especially on the Static publish setting, that a slide does not start playing, until the video is loaded, you get the little spinny circle. Which is fine, I would actually prefer the slide to take a moment to load all the assets and play properly, than result in poorly timed animations and double audio.
Is there a way to force storyline to not play a slide until all the audio is loaded, like it does for a video? Is there an option I'm missing somewhere?
For now all I can do is try and reduce the amount of audio on each slide, and space out the audio clips a bit more. The animations still desync from the first clip, but at least it's less likely to overlap the second.
I welcome any ideas, thanks!
9 Replies
Thank you very much for your replies!
ThierryEMMANUEL I very much agree that this problem is hard to nail down. The course I just finished had several modules split up into different Storyline projects, and only a couple of them had this issue. Also, I don't tend to see it on my end, even when published, but a colleague of mine who is testing on a wifi connection, certainly is. Since not everyone taking the final course will have the best internet connection or devices available, I'm actually thankful for this test.
Unfortunately the timeframe doesn't allow for me to downgrade my storyline version on all these modules and retest things, especially since I took advantage of some of those newer features you mentioned, but I appreciate the insight that it may be related to newer versions.
StevenBenassi Thanks very much for the insight on how Storyline loads these files. I am a bit surprised that the method of combining all the audio into one strip is suggested. I would have figured having a few smaller clips would be easier for them to load in, especially if they are loaded right when the timeline gets to them, and not all preloaded when the slide is loaded.
For example if I have a timeline with 3 short clips on it, say one at 0.5s one at 5 seconds and one at 10 seconds, the 5 and 10 clips wouldn't be loaded in until those respective times yes? So in that case, wouldn't it be better for those clips to be smaller, so they will load faster, rather than one long clip loaded at 0.5 seconds, that would take longer to load and thus increase the amount of time it is desynced from the rest of the timeline?The rest of your suggestions make sense, and I typically do most of those, and while they help, they don't mitigate it entirely.
I did want to ask, if as you say the audio is loaded as the system encounters each clip on the timeline, what about situations where I do have several clips that are handled by a trigger? The way those clips present on the timeline, is as a 'Show Always' clip, filling the length of the timeline. Are these clips all loaded in the begging of the slide, and would all those clips trying to load a the beginning, throw off the clip that is not triggered by a button to be delayed? Something like this:I have a hunch this is true, as most of the slides that encountered this issue did have a similar setup, or had really long clips (over 30s) that I figure are taking longer to load in, than the shorter clips.
I will certainly try the 'one long clip' method in my next project, to see how that goes.Hey MatthewMills-20,
This is a great breakdown of what you're seeing, and your logic absolutely makes sense.
Where things get tricky is that Storyline doesn’t strictly load audio "just-in-time" at the exact moment it appears on the Timeline. This is especially apparent when publishing to SCORM and distributing through an LMS.
While it appears clips at 5s and 10s should only load when the playhead reaches them, the browser/LMS may begin requesting multiple media assets for the Slide as soon as it initializes. This isn’t strictly sequential or optimized per clip timing. It’s more dependent on how the Player and browser queue network requests. So even if clips appear later on the Timeline, they can still compete for bandwidth early on, especially in LMS environments.
Also, each audio clip requires its own file request. In an LMS context, that means:
- Frequent HTTP requests.
- More potential latency per file.
- More chances for slight delays to stack or overlap.
That’s why combined audio can perform more reliably, even if the file is larger. It can help reduce the number of requests and eliminate timing gaps between clips.
Audio that appears as “Show Always” on the Timeline (even if it’s Triggered later) is still part of the Slide’s media assets. In many cases, those files are requested right when the Slide loads. Not when the Trigger fires. Having several Triggered clips, plus a Timeline-based clip that needs to start immediately, can cause conflict. As they may compete at the start, which can delay that first clip and throw off timing.
Having said that, please let us know if the extended clip design works for you!
Thanks MatthewMills-20 . I’ve learnt a lot about this problem, which has certainly given me a few "white" hairs (as we say in French). Well, I’ve nothing but white hairs now, but still.
Matthew, I didn’t quite understand whether you managed to sort out the problem in the end. I hope so. Luckily for me, I was able to downgrade the version of SL. But whilst I’m waiting to finally deliver my two affected projects for two separate clients (five others currently in progress aren’t), I’m juggling between the old version and the very latest one. I haven’t tried exporting again with the 31 March version, due to lack of time.
I’d used the ‘long’ clip technique rather than several short ones, but mainly to logically avoid the short ones overlapping.
I didn’t do much more testing (adding a delay, adding a trigger) once I knew the export was OK for the client, using the old version. (Phew!)
I’ll keep an eye on this discussion to see if Steven answers your questions.
Best regards.
Hi MatthewMills-20,
Sorry to hear that Storyline audio is delayed during LMS playback!
This behavior is likely related to how audio is loaded and buffered when content is delivered through an LMS. In Storyline, audio files on a Slide are not fully preloaded before playback starts. Instead, they're typically loaded dynamically, as the Timeline progresses or when triggered. LMS delivery can also introduce latency and SCORM wrapper overhead processes.
That's why everything works as expected during Preview or when published to Review 360. In those environments, assets are locally available and can be streamed more efficiently.
To mitigate this behavior, we suggest:
- Combining audio clips when possible into a single file per slide. This can help reduce the number of assets that need to load during playback.
- Add a slight delay at the start of each Timeline (e.g., 0.25 to 0.5 seconds) to give the audio extra time to initialize.
- Use 'Play Media' Triggers instead of Timeline-based audio for more control over when audio clips start.
- Check LMS/browser combinations (Chrome vs. Edge) to see if one handles playback more smoothly than others.
Currently, Storyline doesn't support an option that forces itself to fully preload all audio on a Slide before playback starts. I can certainly see how that functionality would help scenarios like yours.
I've submitted your feedback as a feature request, and we'll be sure to notify you if we release a future enhancement that helps!
Hello MatthewMills-20 .
You have described perfectly and precisely a major bug that I encountered on several of my recent projects. It was so bad that my clients rejected the SCORM export: the start of the audio/voice-over tracks is (sometimes) out of sync, meaning they cut off at the end of the timeline; the clips overlap for the same reason; and some audio tracks sound like they have an ‘echo’???. I’ve looked for a solution but haven’t found one in the file. I can’t hear anything wrong in the Preview. The strangest thing is that this does NOT affect ALL my projects. But on the latest project, there were two of us working in parallel, each from home (3 modules for me and 3 modules for him), and all the modules were affected. And the strangest thing of all is that I don’t hear much mention of this massive, catastrophic audio bug in discussion threads like this one. Really odd.
In any case, I don’t have a solution while we wait for the Articulate team to fix this issue, which is preventing me from working properly. But I’ve found a workaround that works. By downgrading Storyline to version 3.106.35891.0 from Dec 8th 2025 (which is the version I’m using right now), all the audio problems disappear. Of course, this ‘old’ version doesn’t support two ‘new’ features (at least). The ‘click to pause’ for videos and the ‘rename a trigger (JS)’. This prevents you from opening your current file with this version. However, if this is the case, you can “delete” your video(s) and JS triggers, open the file with the old version, and then restore your videos and triggers. It works, and even if it’s not ideal, it saved me from a nervous breakdown.
I hope this helps. Let me know. I’m really keen to hear a second, documented opinion on this bug.
Hey ThierryEMMANUEL,
Thanks for jumping in and sharing your experience! I completely understand how frustrating this can feel, especially when the behavior impacts client delivery.
While we recommend authoring on the latest Storyline versions for stability and fixes, this is helpful insight and something we’d like to investigate further. Since you're seeing this issue across multiple projects and versions, do you mind uploading a sample .story file for testing? You can share that file here in the discussion or through a support case.
In the meantime, I have some follow-up questions to help us troubleshoot this better:
- Are you using multiple short clips on the Timeline, Triggered audio, or both?
- Are your audio files externally sourced, AI-generated, or a mix of both?
- Does the behavior occur consistently across all browsers?
Looking forward to hearing from you!
StevenBenassi, I have noticed an increase in the same issues with our audio in Storyline: it either gets clipped or delayed when viewed. We have practiced adding a buffer before and after the audio on the timeline. And still having the issue.
