Lip sync

Multimodal

A dedicated POST /v1/lipsync endpoint — not one more /v1/videos request shape. A driving audio track re-syncs an existing face, in one of two modes depending on the model you pick: image mode animates a still photo (image_url + audio_url), video mode dubs an existing clip's mouth to new speech (video_url + audio_url). There's no prompt field at all, and no duration_secs either — output length always follows the real length of your audio (and, in video mode, your source video too).

Lip sync works from your picture or video and your audio. If you'd rather pick a character from a catalog and give it a script to speak (Arabic and 50+ other languages), use Talking avatars — POST /v1/avatars/videos.

This is deliberately kept off /v1/videos' own start_image_url/input_video_url/input_audio_url fields — those already mean something else there (starting frame, video editing, LTX's own audio-to-video), and combining them for lip sync would be one field-name accident away from a reference-to-video call (input_references/input_audio_references) that generates something new instead of preserving your exact source face/scene and just re-timing the mouth.

Image mode: animate a still photo

import requests, time

job = requests.post(
    "https://videorouter.sh/api/v1/lipsync",
    headers={"Authorization": "Bearer llmr_sk_live_..."},
    json={
        "model": "fal/h3-max-lipsync",
        "image_url": "https://example.com/face.jpg",
        "audio_url": "https://example.com/speech.mp3",
    },
).json()
# -> {"id": "fal:...", "status": "queued", ...}

status = requests.get(
    f"https://videorouter.sh/api/v1/lipsync/{job['id']}",
    headers={"Authorization": "Bearer llmr_sk_live_..."},
).json()

const createRes = await fetch("https://videorouter.sh/api/v1/lipsync", {
  method: "POST",
  headers: { Authorization: "Bearer llmr_sk_live_...", "Content-Type": "application/json" },
  body: JSON.stringify({
    model: "fal/h3-max-lipsync",
    image_url: "https://example.com/face.jpg",
    audio_url: "https://example.com/speech.mp3",
  }),
});
const job = await createRes.json();
// -> {"id": "fal:...", "status": "queued", ...}

const statusRes = await fetch(`https://videorouter.sh/api/v1/lipsync/${job.id}`, {
  headers: { Authorization: "Bearer llmr_sk_live_..." },
});

curl https://videorouter.sh/api/v1/lipsync \
  -H "Authorization: Bearer llmr_sk_live_..." \
  -H "content-type: application/json" \
  -d '{
    "model": "fal/h3-max-lipsync",
    "image_url": "https://example.com/face.jpg",
    "audio_url": "https://example.com/speech.mp3"
  }'
# -> {"id": "fal:...", "status": "queued", ...}

curl https://videorouter.sh/api/v1/lipsync/fal:... \
  -H "Authorization: Bearer llmr_sk_live_..."

Video mode: dub an existing clip

import requests, time

job = requests.post(
    "https://videorouter.sh/api/v1/lipsync",
    headers={"Authorization": "Bearer llmr_sk_live_..."},
    json={
        "model": "fal/sync-lipsync-v3",
        "video_url": "https://example.com/clip.mp4",
        "audio_url": "https://example.com/new-speech.mp3",
    },
).json()
# -> {"id": "fal:...", "status": "queued", ...}

status = requests.get(
    f"https://videorouter.sh/api/v1/lipsync/{job['id']}",
    headers={"Authorization": "Bearer llmr_sk_live_..."},
).json()

const createRes = await fetch("https://videorouter.sh/api/v1/lipsync", {
  method: "POST",
  headers: { Authorization: "Bearer llmr_sk_live_...", "Content-Type": "application/json" },
  body: JSON.stringify({
    model: "fal/sync-lipsync-v3",
    video_url: "https://example.com/clip.mp4",
    audio_url: "https://example.com/new-speech.mp3",
  }),
});
const job = await createRes.json();
// -> {"id": "fal:...", "status": "queued", ...}

const statusRes = await fetch(`https://videorouter.sh/api/v1/lipsync/${job.id}`, {
  headers: { Authorization: "Bearer llmr_sk_live_..." },
});

curl https://videorouter.sh/api/v1/lipsync \
  -H "Authorization: Bearer llmr_sk_live_..." \
  -H "content-type: application/json" \
  -d '{
    "model": "fal/sync-lipsync-v3",
    "video_url": "https://example.com/clip.mp4",
    "audio_url": "https://example.com/new-speech.mp3"
  }'
# -> {"id": "fal:...", "status": "queued", ...}

curl https://videorouter.sh/api/v1/lipsync/fal:... \
  -H "Authorization: Bearer llmr_sk_live_..."

Real price is computed from your file's own probed duration — for video-mode models, that's max(video_secs, audio_secs), never the shorter of the two, since some models can stretch the shorter input to match the longer one. That cost already includes our 2.5% platform fee.

Which models

12 models across 3 providers — fal.ai, Atlas Cloud and Vidu.

Image mode (image_url + audio_url)

ModelProviderPrice

fal/h3-max-lipsyncfal.ai (MiniMax)$0.05–$0.32/s by resolution

fal/sync-lipsync-v3-imagefal.ai (Sync Labs)$0.1333/s

atlascloud/infinitetalkAtlas Cloud (MeiGen-AI)$0.03/s (480p), $0.06/s (720p)

fal/heygen-avatar4-image-to-videofal.ai (HeyGen Avatar 4)$0.10/s, billed in whole seconds

fal/omnihuman-v2fal.ai (ByteDance OmniHuman 2.0, full-body talking video)$0.105/s of audio; audio 4–300 s; optional prompt for scene/camera

atlascloud/omnihuman-v2Atlas Cloud (ByteDance OmniHuman 2.0, same model, lower price)$0.0896/s of audio; audio 4–300 s; native 720p; optional prompt for scene/camera

vidu/s1-avatar-offlineVidu (S1 talking avatar, lip sync + body motion)$0.005/s of audio, rounded up; 540p or 720p, same price; typically 1–7 min

Video mode (video_url + audio_url)

ModelProviderPrice

fal/sync-lipsync-v3fal.ai (Sync Labs sync-3)$0.1333/s

fal/sync-lipsync-react-1fal.ai (Sync Labs)$0.1667/s, max 15s in/out

fal/sync-lipsync-v2-profal.ai (Sync Labs lipsync-2-pro)$0.0833/s

fal/sync-lipsyncfal.ai (Sync Labs lipsync-1.9, the original)$0.70/min (~$0.0117/s)

fal/sync-lipsync-v2fal.ai (Sync Labs lipsync-2)$0.05/s

fal/veed-lipsync-v2fal.ai (VEED)$0.07/s

fal/heygen-v3-lipsync-precisionfal.ai (HeyGen)$0.10/s

fal/heygen-v3-lipsync-speedfal.ai (HeyGen)$0.05/s

Atlas Cloud rows bill through Atlas Cloud's reserve-then-settle flow (same as every other Atlas Cloud video model) — the price shown is a pre-call estimate; the real charge settles from Atlas Cloud's own completed-job invoice. Every model here also shows up under the Lip Sync filter on the models catalog.

Not yet supported

Avatar/digital-human models that need a voice_id or avatar selection (e.g. HeyGen's own Avatar-IV/Digital Twin) aren't onboarded — this endpoint has no avatar/voice-selection concept, only a real image or video you supply yourself. Kling LipSync and Hedra aren't wired in yet either. Self-hosted open-weight options (LatentSync, MuseTalk) would need their own GPU deployment, not a simple resale row, and aren't on this platform today.