We’ve just released version 3.6.6: Download here
This update introduces the EnableSync parameter:
Good Morning @K3, Thanks for the hotfix release. I presume, the new plugin 3.6.6, we still add MinBufferDuration=7, AudioLipSyncRatio=1 lined in the Extra Params in project settings? Unless there is an actual setting in the blueprint now.
MinBufferDuration=8, EnableSync=0 You can try these parameters.
Hi @K3, Here is a video showing the effects of v3.6.6 and the above settings you suggested. Please request access to the file. https://drive.google.com/file/d/1ryWcoC-5VRNK5B8L898t41ULEGlq_wX4/view?usp=sharing
As far as I can see, there’s no stuttering?
There is audio cutout, Lip Sync Drift, Lips stop moving while audio continues. the stuttering hasn’t happened correct
Yes, because Sync is disabled, as you can see.
EnableSync=0
Tried it with this setting MinBufferDuration=8, EnableSync=0.5 and the same as well as EnableSync=1
Unable to find the sweet spot setting for the Min Buffer Duration and Enable Sync. The voice cuts off mid-way, the lips stop moving but audio continues and constantly getting the Error 14 resulting in full loss of functionality intermittently but higher rate today.
Please read the instructions I shared earlier carefully. Here’s a quick recap of what the updated parameters do:
EnableSync: 0 disables lip-sync synchronization, 1 enables it.
1, the system waits for lip-sync data before playing audio, which can cause stuttering.AudioLipSyncRatio: Determines how much lip-sync data must be received before audio playback starts.
1 = wait for full data, 0 = start playing immediately.MinBufferDuration: Adjusts the buffering time. A higher value reduces stutters but increases response delay.
For your case, please try:
MinBufferDuration=3
AudioLipSyncRatio=0.3
EnableSync=1
These changes are meant as a temporary workaround to reduce stuttering issues. Please make sure you understand how each parameter affects playback before adjusting them.
Thanks @K3 will give it a try after dinner. 
Hi everyone,
just sharing a new update from our production deployment, which unfortunately shows a significant regression.
After the update to Convai SDK 3.6.4, the system had worked surprisingly well over the weekend (Aug 3–4). We tested it personally on site and remotely, and received consistent positive feedback from the client — stuttering and interruptions were nearly gone, response times were acceptable, and lip sync remained in place in almost every case.
However, starting yesterday and continuing today (Aug 5–6), things have gotten noticeably worse again.
Here’s a summary of the report from the client (translated from Italian):
“This morning, the system is again very problematic. Sometimes it takes more than 15 seconds to formulate a reply. Toward the end of the sentence, the lips stop moving, although the audio continues. Then, the microphone icon appeared and the system began responding in bursts, and at one point completely froze. From that moment on, it didn’t work properly anymore.”
On the days when the system was working well, I personally ran tests that confirmed the smooth experience, so this isn’t just hearsay.
At this stage, I haven’t yet tested the new config parameters (AudioLipSyncRatio, EnableSync, etc.) introduced in the latest suggestions. I’ll try those shortly and follow up as soon as I have new results.
Thanks again for all the detailed posts — following the thread closely.
Quick update on our latest tests in production.
Yesterday, I deployed a new release with Convai version 3.6.6 (Unreal 5.5) with these parameters:
ExtraParams=MinBufferDuration=2,AudioLipSyncRatio=0.3,EnableSync=0
The system performed well between 10:00 and 15:00 (Italian time) but then started “stuttering” again.
This morning, I updated the parameters to:
ExtraParams=MinBufferDuration=3,AudioLipSyncRatio=0.3,EnableSync=0
With this configuration, the system has worked smoothly for the entire day — response times are acceptable, and there have been no interruptions (lip sync aside for now).
I’m aware that AudioLipSyncRatio is meaningless with EnableSync=0. For the moment, I’ve preferred to disable lip-sync synchronization to ensure a consistently smooth and interactive user experience.
The goal now is to see if the system can remain stable for 7 consecutive days with these settings. Once audio performance is fully stable, we’ll move on to fine-tuning the correct configuration for lip sync.
If nothing changes, I’ll share a new update in 7 days.
Hi everyone,
I’d like to share a final update from our side: the application is now running smoothly in production and this configuration seems to be resolving the issue.
For transparency, I haven’t tested alternative setups yet (so for now EnableSync=0), but this setup has been stable and the client reports a consistently good experience.
Since several people have been involved in this thread (@heivoll, @juliana, @Jeasy_Sehgal), I’d like to leave it open for a few more days before marking it as “solution” — just to give others a chance to share additional feedback if needed.
Thanks again to the Convai team for the support and for following up so closely on this!
Hi @K3,
The sync issue with plugin version 3.6.6 has returned since yesterday. The character’s lip movement stops, and the audio continues.
Extra Parameters used are: MinBufferDuration=8, AudioLipSyncRatio=0.3, EnableSync=1
Just to share my experience: at the moment I have no evidence of interruptions or cut-offs in the audio stream — it has been working consistently well on our side.
That said, I want to note that my current setup is running with EnableSync=0, so my results might differ from those who are testing with lip-sync enabled.
@omar.venturi Thanks! I’ll try your solution. 
Hello, we are experiencing the same issue with an Elevenlabs voice. Convai is set to 3.6.6, and none of the extra parameters are providing good results. Either there is stuttering, or the lip sync ends before the audio is finished.
@K3 When can we expect a proper solution?
Char ID:
0ad94f5a-fdc4-11ef-aae4-42010a7be01a
We’re experiencing the same issue. We’ve tried all the possible solutions mentioned here, but the problem persists. Even projects that were working perfectly a couple of months ago are now unusable. This is a serious problem, especially for professional use. We are using custom Elevenlabs voices. Plugin version 3.6.6 and we tried any combination with extra params.
We are also facing the same issue. Convai pls solve this as we are already paying for the Subscriptions and expect a solution or reply from your side so we know the status and by when it will be solved.