What do Sync Labs lip-sync models document for inputs, face constraints, duration limits and price (Oct 2026)?

Sync Labs docs (captured 2026-10-23) list lipsync-2, lipsync-2-pro and sync-3 plus legacy lipsync-1.9.0-beta. lipsync-2/2-pro render faces at 512x512 (fine for most 1080p; large faces look softer), infer in independent 2-second chunks and need natural speaking motion in the input video: still-frame segments get no lip motion. Obstruction detection is optional on 2/2-pro (slower), built into sync-3, which also handles profiles/over-shoulder and outputs 4K. For multiple faces, mask or crop externally. Max duration depends on plan, 1 min (Hobbyist) to 30 min (Scale+); free tier 3 generations/month, 20 s each (sync-3: 1 generation, 15 s). Per-second prices at 25 fps: 1.9 beta $0.02-0.025, lipsync-2 $0.04-0.05, 2-pro $0.067-0.083, sync-3 $0.107-0.133. Isolate vocals for song lip-sync. Open alternative: LatentSync 1.6 (Apache-2.0 repo, 2025-06) needs 18 GB VRAM for inference (1.5: 8 GB), trained at 512x512, and its pipeline uses InsightFace landmarks (InsightFace pretrained models carry their own licence terms; check before commercial use). Curator qualifications: All cited excerpts located in the live source text by curator GET 2026-10-23 (bytes hashed, discarded). sync-3 price '$0.107 - $0.133/sec' located in the page table text (excerpt formatting differed); free tier '3 generations/month ... max 20s ... (sync-3: 1 generation/month, 15s max)' located on the quickstart page. 'InsightFace pretrained models carry their own licence terms' is discovery inference not checked in this batch; labelled inference. Limitations: Help/doc pages are undated or change without notice; statements are as served on 2026-10-23. Languages and consent terms for Sync not found on these two pages; InsightFace licence implication is an inference to verify. Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

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  "citations": [
    {
      "url": "https://sync.so/docs/models/lipsync",
      "note": "line 34-35; line 58; line 75; lines 78-82; line 10; lines 108-111"
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    {
      "url": "https://sync.so/docs/quickstart",
      "note": "line 34-35; line 58; line 75; lines 78-82; line 10; lines 108-111"
    },
    {
      "url": "https://raw.githubusercontent.com/bytedance/LatentSync/main/README.md",
      "note": "line 34-35; line 58; line 75; lines 78-82; line 10; lines 108-111"
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