TikTok向けAI動画ジェネレーター：2026完全ガイド

TikTok is the hardest platform to generate for and the easiest to publish to. Hard, because the feed is a scroll-stop competition decided in about 1.5 seconds and the platform re-encodes everything you upload. Easy, because a single 9:16 clip with a working hook needs no editing suite, no crew, and no shoot day. This guide covers the specs that survive TikTok's compression, the hook structures that hold attention, and a three-clip assembly workflow you can repeat every day.

Get the Specs Right Before You Generate

Reframing after generation loses composition, so decide the output format first. TikTok's native canvas is 1080×1920 at 9:16. Generating 16:9 and cropping later leaves you choosing between cutting the subject or letterboxing — both read as recycled content.

Start in AI Short Video, which defaults to platform-native 9:16 rather than making you crop a horizontal render.

The First 1.5 Seconds Decide Everything

TikTok measures whether people keep watching before it decides who else sees the video. That makes the opening frame a production priority, not an afterthought. Four hook patterns that generate reliably:

• Motion-in-frame: the subject is already moving when the clip starts. Static openers lose. Prompt it explicitly: "already in motion at frame one".
• Pattern interrupt: an unexpected object, scale, or material in an otherwise ordinary scene. Generation is unusually good at this because impossible imagery is cheap.
• Result first: open on the finished state, then show how it got there. Works for anything with a visible transformation.
• Direct question on screen: text hook over moving b-roll. The lowest-risk option because it does not depend on face or lip-sync quality.

The Three-Clip Workflow

Because most models render 5–10 seconds natively, a TikTok is an assembly, not a single generation. The repeatable structure:

1. Clip 1 — hook (0:00–0:02): highest-motion shot you have. Generate this one two or three times and keep the best; it carries the whole video.
2. Clip 2 — substance (0:02–0:09): the demonstration, reveal, or explanation. One idea only.
3. Clip 3 — close (0:09–0:12): the result plus a reason to act. Keep the CTA spoken or on-screen, not both.

Generate all three with the same subject description so the visual identity holds across cuts. Changing wording between clips is the most common cause of a character or product looking like two different things.

Prompt Templates That Work on TikTok

Captions, Text, and the Safe Zone

Much of TikTok viewing happens muted, so burned-in captions are not optional. Two rules: keep all text inside the middle 60% of the frame vertically, and never ask the model to render legible words — generate clean footage and add text in the edit. Video models still produce garbled type, and misspelled on-screen text reads as low effort.

AI Labelling: What TikTok Actually Requires

TikTok requires realistic AI-generated content to be labelled, and it provides the label in the upload flow. Using it does not suppress reach. What does cause problems: presenting a synthetic person as a real customer, and third-party watermarks, which the algorithm treats as reposted content. If your clip features a realistic human, label it — see the disclosure section in the AI UGC video guide for the FTC and Meta equivalents.

Why Faceless Often Outperforms on TikTok

Faces are the hardest thing for video models to keep consistent across frames, and TikTok viewers detect a wrong face instantly. Product shots, hands, environments, and abstract motion hold up far better. If your concept does not need a presenter, the faceless approach will land in fewer attempts. When you do need a person on camera, AI UGC Video ships creator personas built for this register.

Posting Cadence and What to Measure

• Cadence: three to five posts per week. Generation removes the production bottleneck, so the real limit is having something worth posting.
• The metric that matters: 3-second retention. If viewers do not reach three seconds, nothing downstream matters. Fix the hook before touching anything else.
• Then: completion rate, which tells you whether the clip is too long for its idea. A 12-second video finishing at 60% usually means it should have been eight seconds.
• Variant testing: keep clips 2 and 3 fixed, swap clip 1. This isolates hook performance, the same discipline paid media uses in the AI ad video workflow.

Start Generating

Open AI Short Video and generate one hook clip — highest motion, 5 seconds, 9:16. Free signup credits cover the first several attempts, which is roughly what it takes to find a hook that holds. When you want a different model for a specific shot, compare models and route that shot to whichever engine owns it.