Hey everyone, I've been putting Synthesia through its paces for some technical explainer videos and onboarding content. While the overall tech is impressive, I keep hitting a consistent snag that pulls me right out of the "this is real" feeling: the lip-sync, especially on certain consonants, still feels noticeably unnatural.
I'm focusing on English avatars, and I've noticed it most on plosive sounds like **p**, **b**, **t**, **d**, **k**, and **g**. The mouth movement often feels too soft or slightly mistimed—like the avatar is saying "b-ase" instead of a sharp "base." It's less about the audio being out of sync and more about the viseme (the visual mouth shape) not matching the force or closure of the consonant sound. This is particularly jarring in words with repeated consonants or technical terms.
Here’s a concrete example from a script I used:
```txt
"The deployment pipeline pushes the built Docker image to the registry."
```
On the word "pushes," the "p" lip closure is weak, and the transition to the "sh" sound seems off. On "Docker," the hard "D" and "k" sounds don't quite land with the visual impact I'd expect.
I've tried a few things to mitigate this:
* **Adjusting the speech speed:** Slowing it down sometimes helps, but it makes the delivery sound robotic.
* **Re-phrasing scripts:** Avoiding words with hard consecutive consonants (e.g., saying "container" instead of "pod").
* **Trying different avatars and voices:** Some pairings are definitely better than others, but the underlying issue persists.
I'm curious if others in the community are observing the same, or if I'm just hyper-focused on it. For those using it for similar technical content:
* Which avatars/voices have you found to have the *best* lip-sync accuracy?
* Are there any script formatting tricks (like adding pauses or emphasis marks) that actually help?
* Does this improve noticeably with the higher-tier plans or specific video quality settings?
I want to love this tool—it saves so much time for updating documentation videos—but this one detail keeps holding me back from a full-throated recommendation. Any insights or shared experiences would be super helpful.
— francesc
— francesc
No, you're definitely not the only one. It's the fundamental compromise of the current tech stack. They're mapping a finite library of visemes, trained on general speech patterns, onto a synthesized audio track. Those plosives require a sharp, full occlusion of the lips or tongue against the palate that the model just isn't generating forcefully enough because it's averaging across its training data.
You can try to brute-force it by editing the phonetic script manually, but it's a pain. I've had some marginal success inserting exaggerated phonetic markers or even adding artificial pauses before hard consonants to give the animation engine a chance to hit the keyframe, but it breaks your scripting flow. For technical terms, it's often worse because the training corpus likely had less exposure to words like "Kubernetes" or "Docker" spoken in isolation.
Been there, migrated that