# AI effect from a prompt > How a neural network changes the video on a range from your description — “make it snow”, “evening neon light”: where to start it, price and what to know. Source: https://docs.slicer.media/en/guide/ai/effect/ An AI effect changes the reel's picture itself on the range you choose, based on your description: it adds snow or fireworks, changes the light and time of day, stylizes the shot. It's not a filter over the video — the neural network redraws the frames of the range according to your description. The reel's sound stays the same. **Demo (Web):** 1. Click a clip on the timeline and press “AI video” 2. The “AI effect from a prompt” sheet opens — the range already matches the clip 3. Move “End” so the range is 5 seconds 4. Type “Let soft snow fall” — the button shows the price “Apply · ≈ … tokens” ## Where to start it - **In the editor:** select a clip and press **AI video** — the range matches the clip's time right away. - **In any project section:** the “⋯” menu in the header → **AI effect**. The effect is available for a finished reel while its source files are stored. While a previous effect is running, the menu item shows **Applying the effect…** and a new one can't be started. ## Applying it ### 1. Choose the range At the top of the **AI effect from a prompt** sheet is the range, for example “From 2.0 s to 7.0 s · 5.0 s”. The **Start** and **End** sliders move its edges, **Whole reel** picks a range from the start of the reel. The range is 2 to 30 seconds long: if the reel is longer, **Whole reel** takes the first 30 seconds. ### 2. Describe the effect Write what should change in the frame — at least 3 characters. For example: “make it snow”, “evening neon light”, “add fireworks outside the window”, “turn the scene into a watercolor painting”. ### 3. Start Press the button with the price — “Apply · ≈ N tokens”. The effect is prepared on the server; you can close the app. While it runs, the “⋯” menu shows **Applying the effect…**; then the reel is rebuilt — you can follow it on the **AI effect** run card. When everything is done, the reel updates and a new version appears in the [history](https://docs.slicer.media/en/guide/projects/history/). ## Price An AI effect is charged **at cost** — exactly what the AI service charges, with no markup. You pay for each started second of the range, and no less than for 2 seconds. The price is shown on the button before you start and changes with the range length; the sheet explains: **Costs exactly what the AI service charges, no markup. The actual price is charged — never more than shown.** - While the effect is being made, the price is reserved on your balance, rounded up to a whole token — so you need at least one free token. - The actual price is charged, never more than shown, and **only if the effect worked** and the reel was rebuilt. If something went wrong, the tokens come back and the reel stays as it was. How at-cost pricing works — [Tokens, packs and the free reel](https://docs.slicer.media/en/guide/pricing/#at-cost). ## What to know > **Important.** An AI effect changes **the already built video** — the reel's last export. If you've edited clips in the editor, press **Export** first so the range matches what you see in the preview. - The effect is baked into the reel's picture. If you later change clips — their order, edges, cut words, clip settings, frame or zooms — the effect is dropped on export; the editor warns about clip changes before export. Changing the [aspect ratio](https://docs.slicer.media/en/guide/editor/format-cover/) or the “Intro push-in” setting also drops it. Edits to caption text, style, the hook, plaques, cards, emoji and music leave the effect alone. - So an AI effect is best done last, when the edit is final. - The sound doesn't change — the neural network works only with the picture. Captions and graphics are drawn on top of the new video. - The network processes a long range in parts and stitches them back together. - Platforms ask you to label videos with AI effects: turn on **Made with AI** when publishing ([Publishing](https://docs.slicer.media/en/guide/publish/platforms/)). ## Writing a prompt - Describe the change in the frame, not an editing action: “large snowflakes falling”, not “make an effect”. - Add details of light, weather, style: “warm sunset light, soft shadows”. - One effect — one idea: first the snow, then, if needed, another range with another idea. - Short ranges are cheaper and more precise: pick exactly the moment where the effect serves the story. ## What's next - [Clip effects](https://docs.slicer.media/en/guide/editor/effects/) — free effects without AI. - [History and versions](https://docs.slicer.media/en/guide/projects/history/) - [Operation prices](https://docs.slicer.media/en/guide/help/prices/)