Lip Sync

Sync audio to a character’s face to create a talking head video.

Overview

The Lip Sync node takes a portrait image and an audio track (speech/voiceover) and generates a video where the character’s lips move in sync with the audio. Supports optional motion prompts for head and expression movements.

It can also dub an existing video: HeyGen Lipsync Precision, Sync Lipsync 2 Pro, Sync Lipsync v3, and Volcengine Lip Sync take a source video plus a replacement audio track and re-animate the lips to match the new speech, billed per second of output. Volcengine is the cheapest modern dubbing option and the only one with multi-speaker scene detection + speaker ID (basic mode).

Configuration

Field Type Default Description
Provider Select kling-avatar AI model for lip sync
Resolution Select 720p Output resolution: 480p/720p (most KIE providers); OmniHuman 1.5 is 720p/1080p (default 1080p); only the full seedance-2 adds 1080p / 4K (seedance-2-fast and seedance-2-mini are 480p/720p only)
Motion Prompt Textarea — Optional: describe head/expression motions (KIE providers only)

OmniHuman 1.5 options

omnihuman-1-5 is ByteDance’s premium prompt-directed talking avatar (image + audio → performing avatar). It animates people, pets, or anime at any aspect ratio, and uses the motion prompt to direct the performance.

Field Type Default Description
Motion Prompt Textarea — Directs the performance (e.g. “sing confidently into a microphone”)
Resolution Select 1080p 720p or 1080p (no 480p)
Fast Mode Toggle Off Trade some quality for faster generation (pe_fast_mode)
Seed Number -1 Reproducibility — same seed + inputs → near-identical result. -1 = random

Seedance 2 (image + audio avatar)

seedance-2, seedance-2-fast, and seedance-2-mini are also offered on the lip-sync surface. They are ByteDance’s multimodal video models, which do native phoneme-level lip sync in 8+ languages when fed an audio track alongside a portrait — routed through the image-to-video provider with the audio passed as reference_audio_urls (not the dedicated lip-sync flow). The full seedance-2 accepts 1080p and 4K output; seedance-2-fast and seedance-2-mini are 480p/720p only (no 1080p SKU). Full controls, durations, and per-second pricing live on the Generate Video page (e.g. 4K 8s = 416 cr, 1080p 8s = 204 cr). seedance-2-fast requires each reference audio clip to be ≤ 15.2 s.

HeyGen Lipsync Precision options

Field Type Default Description
Dynamic Duration Toggle On Adjust the output length to match the new audio
Remove Music Track Toggle Off Strip background music from the source video
Speech Enhancement Toggle Off Improve speech clarity in the output

Sync Lipsync 2 Pro options

Field Type Default Description
Sync Mode Select loop Behavior when audio/video durations differ: loop, bounce, cut_off, silence, remap
Temperature Slider 0–1 0.5 How expressive the lip sync can be
Active Speaker Detection Toggle Off Lip-sync whoever is speaking in the clip

Sync Lipsync v3 options

sync-lipsync-v3 is the fal.ai-hosted sync.so v3 model. It exposes only the sync-mode lever.

Field Type Default Description
Sync Mode Select loop Behavior when audio/video durations differ: loop, bounce, cut_off, silence, remap

Volcengine Lip Sync options

volcengine-lipsync is the KIE-hosted Volcengine video-to-video dubbing model. It re-syncs an existing clip’s lips to a new vocal track and is the cheapest modern dubbing option (2 CR/s). Output length follows the audio (the source video is trimmed if longer, looped if shorter).

Field Type Default Description
Mode Select lite lite = single-person frontal, faster · basic = complex scenes, enables multi-speaker scene detection + speaker ID
Separate vocals Toggle Off Strip background noise from the driving audio
Scene detection + speaker ID Toggle Off Basic mode only — segment scene cuts and identify who is speaking (multi-speaker clips)
Loop video if audio is longer Toggle On Lite mode only — loop the source video when the audio runs longer than it
Reverse loop Toggle Off Lite mode only — ping-pong the loop (requires looping to be on)
Template start time Number (s) 0 Where in the source video to start driving the lips (advanced)

Inputs & Outputs

Inputs:

Outputs:

HeyGen Lipsync Precision, Sync Lipsync 2 Pro, Sync Lipsync v3, and Volcengine Lip Sync replace the audio on a video input (not a portrait image).

Audio Length Limits

Provider Max input audio
kling-avatar (Standard) 5 minutes
kling-avatar-pro (Pro) 5 minutes
infinitalk 15 seconds
omnihuman-1-5 60 seconds
heygen-lipsync-precision 5 minutes*
lipsync-2-pro 5 minutes*
sync-lipsync-v3 5 minutes*
volcengine-lipsync 5 minutes

For the KIE providers (kling-avatar(-pro), infinitalk, volcengine-lipsync), audio longer than the cap is auto-trimmed before the upstream call. Long-audio runs on kling-avatar(-pro) and volcengine-lipsync can take tens of minutes — the editor polls for up to ~1 hour before timing out.

* For HeyGen Lipsync Precision, Sync Lipsync 2 Pro, and Sync Lipsync v3 the 5-minute figure is the per-second credit-reservation ceiling, not a hard trim — longer clips reserve at the 5-minute tier.

Credit Cost

Kling AI Avatar and OmniHuman 1.5 bill per-second. Credit reservation buckets to the next supported tier; any reserved credits beyond the actual cost are refunded once the job completes.

Provider Per-second 15s 30s 1min 2min 5min
kling-avatar (720p) 2 CR/s 30 60 120 240 600
kling-avatar-pro (1080p) 4 CR/s 60 120 240 480 1,200
omnihuman-1-5 (720p/1080p) ~6.75 CR/s 102 203 405 — —

omnihuman-1-5 is capped at 60s of audio (longer is auto-trimmed), so only the 15s / 30s / 60s tiers apply. Resolution (720p vs 1080p) does not change the price.

HeyGen Lipsync Precision, Sync Lipsync 2 Pro, and Sync Lipsync v3 also bill per second of output, bucketed to the same 15s / 30s / 1min / 2min / 5min tiers:

Provider 15s 30s 1min 2min 5min
volcengine-lipsync 30 60 120 240 600
heygen-lipsync-precision 51 101 201 401 1,001
lipsync-2-pro 63 125 250 500 1,249
sync-lipsync-v3 100 200 400 800 2,000

The credit chip updates once the audio is wired (the node probes its duration). When the duration is unknown, the 5-minute tier is reserved.

Supply audioDurationSec for accurate pricing. When calling sync-lipsync-v3 or volcengine-lipsync via API/SDK, pass the output duration in seconds so the reservation buckets to the correct tier. If it is absent, the request is billed at the 5-minute ceiling (sync-lipsync-v3: 2,000 CR; volcengine-lipsync: 600 CR) with no refund — these per-second models commit the reserved bucket verbatim. The editor probes the duration automatically once the audio is wired.

InfiniTalk and Hailuo Avatar use flat per-call pricing (see admin → Models).

Best Practices

Common Use Cases

Tips