MAJORFailure Reference

Kling Lip Sync Failure — Refund Guide

Technical Classification

Phoneme-Viseme Misalignment

Phoneme-Viseme Misalignment on Kling occurs when the visual mouth shape (viseme) fails to match the audio phoneme being spoken. Kling supports lip-sync workflows where users provide an audio track or a dialogue prompt — but the model's viseme generation is statistical and frequently produces wrong mouth shapes, particularly on bilabials (p, b, m) and rounded vowels (o, u, w). The result is uncanny dubbing-style speech.

How to identify this failure

✕Mouth open during silence (consonant b, p, m has lips closed)
✕Lips closed during open vowels (a, e, i)
✕Mouth shape too small for loud or shouted dialogue
✕Visible jaw motion with no audio to match
✕Sync drift accumulates over 3+ seconds of dialogue

Real generation examples

Prompt used

"A teacher saying 'Please open your books to page five' at a chalkboard"

Failure observed @ 0:00 → 0:04

Mouth open during "p" sounds and closed during "ee" — completely inverted

Prompt used

"News anchor reading a headline about climate change"

Failure observed @ 0:02 → 0:05

Lip motion stops at 0:02 while audio continues for full 5 seconds

Documentation strength

If you need to escalate

HIGH — Lip-sync is a marketed Kling capability for video dubbing and avatar use cases. Refund tickets with paired audio + still frame evidence are honoured.

AVA is a pre-purchase prevention tool, not a post-purchase recovery tool. Platforms generally do not guarantee credit refunds for output-quality failures; goodwill credits are at each platform's discretion. The strength rating reflects how well-formed your support ticket can be, not a promised outcome.

Prevention + documentation steps

01
Score your prompt before you generate
Run your prompt through AVA's pre-flight scoring against the Phoneme-Viseme Misalignment pattern. Green light = generate. Yellow/red = rewrite using the suggested fix before you commit credits.
02
Capture Generation ID + timestamp if it failed anyway
Find the Generation ID in the URL or share link. Note the exact time when the Phoneme-Viseme Misalignment first appears (e.g. "failure first visible at 1.2s"). Timestamped evidence is significantly stronger than a general complaint.
03
Use the correct technical term in your support ticket
Describe this failure as "Phoneme-Viseme Misalignment". This term maps to a recognised internal workflow in the support system and routes the ticket to the right team.
04
Submit via the correct support channel
Runway has no direct email intake. Pro+ plan: open the in-app AI Assistant (help widget bottom-right of app.runwayml.com), describe the failure with the technical term, attach evidence. Free/Standard plan: human support isn't available — your channel is Discord #community-help with @On Call - Moderators.

Frequently asked questions

Does Kling refund credits for lip-sync failures?

Yes — Kling support honours refunds when phoneme-viseme misalignment is shown via paired audio timestamp + still frame. Cite "Phoneme-Viseme Misalignment" in the ticket.

Why does Kling mismatch mouth shapes to audio?

Kling's lip-sync head learns viseme generation statistically from training video — without explicit phoneme-to-viseme rules. Bilabial closures and rounded vowels are undertrained, so the model produces visually plausible but linguistically wrong mouth shapes.

How do I improve Kling lip-sync quality?

Keep dialogue clips short (≤ 3 seconds). Avoid consonant-dense words. Use side-profile framing where mouth shape is partially obscured. AVA flags dialogue-heavy prompts as lip-sync risk before generation.

Score your prompt

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Paste your prompt and the platform you intend to use. AVA returns a red/yellow/green score against this specific failure mode plus a concrete rewrite if the risk is high.

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