Not every video starts with a finished script. Sometimes you have a topic, a product, or a question — and nothing else. CelestiAI's topic-to-video flow takes that one line and writes a script built to fit your target length, then animates, narrates, and captions it end to end. Here's how to go from a single sentence to a ready-to-post video.
What you'll need
- A free CelestiAI account.
- A topic — anything from "why index funds beat savings accounts" to "5 signs your skincare routine is too complicated."
- A target length: from 30 seconds up to long-form.
Step 1: Start from a topic instead of a script
In the Script-to-Video screen, switch from "paste a script" to the topic mode. This tells CelestiAI to write the script for you rather than use yours word for word.
Step 2: Describe your topic clearly
Type your topic in plain language. The clearer the angle, the sharper the script:
- Weak: "skincare"
- Stronger: "why layering too many skincare actives causes irritation — and a simpler routine"
Include the audience and the takeaway if you can. "Explain compound interest to 20-somethings who just started their first job" gives the writer far more to work with than "compound interest."
Step 3: Pick a length
Choose your runtime from the length selector, starting at 30 seconds. This is the single biggest lever on the script:
- 30–60 seconds → a tight single-idea short for Reels, Shorts, and TikTok.
- 2–5 minutes → a fuller explainer with setup, examples, and a payoff.
- Longer → documentary-style chapters for YouTube.
CelestiAI writes to fit the length you pick — no more trimming a 10-minute script down to fit a 1-minute slot.
Step 4: Review the generated script
Before rendering, read the script it produced. This is your chance to steer it. Because the words drive every scene, editing here is the highest-leverage edit you can make:
- Reorder points so the hook lands first.
- Cut anything that doesn't earn its runtime.
- Add your own product name, statistic, or CTA where it belongs.
You're now back in the normal Script-to-Video flow — your generated script becomes the source of truth.
Step 5: Choose template and voice
Pick a motion template that matches the topic's tone and a narrator from the voice library (natural Thai and English are built in). Then generate. CelestiAI animates each line, times captions to every word, adds a hook, chapters, and pattern interrupts, and lays an original music bed underneath.
Step 6: Download from My videos
When the render completes, your finished MP4 is waiting in My videos — narration, motion graphics, captions, and music in one file, ready for YouTube (16:9) or Shorts/Reels/TikTok (9:16).
When topic-to-video is the right choice
- You're posting daily and need to move from idea to upload fast.
- You have expertise but hate writing. Describe the angle; let CelestiAI draft it.
- You're testing angles. Generate three short topic-based scripts from three angles and see which performs.
Tips
- Give it a specific promise. Topics phrased as a clear benefit or curiosity hook write better scripts.
- Match length to platform. Shorts want one idea; YouTube tolerates a build.
- Edit the script, not the pixels. Ten seconds tightening the script beats an hour fighting the render.
Common mistakes
- Vague topics. "Marketing tips" gives the writer nothing; "3 pricing mistakes new coaches make" gives it a spine.
- Wrong length for the platform. A 4-minute script forced into a Short will feel rushed.
- Skipping the script review. It's the one place small edits pay off big.
Wrapping up
Topic-to-video removes the blank-page problem. Describe what you want, choose a length, and let CelestiAI write and produce the whole thing. You stay in control at the script — which is exactly where control matters most.
Start free at celestiai.co and turn your next idea into a video in one sitting.