Korean Lip Sync Accuracy in Unity (LipSync Sample)

What do you need help with?

Question

Installation method

Unity Asset Store

Issue area

Lip Sync / Facial Animation

Impact

Normal - something is not working as expected

Unity version

6000.4.12f1

Convai Unity SDK version

4.3.0

Target platform

Unity Editor

Where does it happen?

Sample scene

Short summary

Lip sync works well in English but appears significantly less accurate when the character speaks Korean in the Unity LipSync Sample.

What happened?

ello Convai Team,

I’m currently testing the Unity SDK using the LipSync Sample scene.

I noticed that lip sync works very well when my character speaks English. The mouth movements closely match the spoken audio.

However, when I configure the character to speak Korean, the lip sync quality becomes noticeably worse. The generated Korean speech audio sounds correct, but the mouth movements do not seem to match Korean pronunciation accurately.

To make sure the issue wasn’t caused by my avatar, I tested using the original LipSync Sample without modifying the character or blendshapes. The behavior was the same:

English lip sync looks natural.
Korean lip sync appears much less accurate.

Since the same character and setup are used for both languages, I’m wondering whether Korean lip sync is currently supported differently from English or if there are additional settings required for Korean.

What did you expect?

I expected Korean lip sync quality to be comparable to English when using the same sample scene and character.

Steps to reproduce

Open the Unity LipSync Sample scene.
Configure the character to speak English and start a conversation.
Observe that the mouth movements closely match the speech.
Change the character language to Korean.
Start another conversation.
Observe that the mouth movements no longer match the Korean speech as accurately.
Unity Console errors or build logs
No errors or warnings related to lip sync.

I checked the relevant documentation, resources, and similar forum posts before posting.

on

I confirm that I did not include API keys, tokens, passwords, secrets, private character data, private conversation logs, or customer data.

on

Please make sure you are using the latest version of the Convai Unity SDK, as it includes lip sync improvements.

At the moment, lip sync works best in English. For other languages, including Korean, some reduction in lip sync accuracy can be expected.