Effects

---
name: effects
description: Pick the right editing effect for the moment and genre (food, travel, daily vlog, review/unboxing, product ad, talking head, real estate, event/MV) and make it with BashCut's native tools — transitions (dissolve, whip, blink, zoom, spin, shutter, wipe), speed ramps, freeze frames, reverse, punch-in, keyframe motion (Ken Burns, animated titles), split moments, text presets, word-by-word captions, stickers and matching SFX — or say plainly when an effect is not possible yet. Use when the user asks "hiệu ứng", "effect", "chuyển cảnh", "transition", "speed ramp", "freeze", "chữ nhảy", "làm giống CapCut", "zoom vào màn hình", "tua nhanh", or when a cut feels flat and needs emphasis.
---

# Effects: when, then how

Reply in the user's language. Decide **when** first; most cuts should stay hard cuts. With a `[Scope]` (Send to Agent), work only on those items (`bc:edit-workflow`).

## When

- **Effects serve a moment, not the whole video.** One or two special transitions per video (the hook, a
  location change); everything else is a hard cut on a sentence, a beat or an action.
- **Choose the transition by how different the shots are:** new place → whip, shutter or cover-the-lens; same
  place with a time skip → blink or a jump cut; product or dish reveal → speed ramp or freeze into the reveal
  with a hit.
- **Every visual motion gets a matching sound**, sized to it (see `bc:audio-mix`). Punchline → cut all music and
  SFX for 1–2 s.
- Whip pans move the same direction on both sides of the cut.
- Cinematic style is the opposite: hard cuts, no whoosh on cuts, one special transition per video; the colour
  look and serif captions carry the feel.

| Genre | Fits |
|---|---|
| Food / travel | whip, cut on action, place cards, pop stickers, speed ramp on food action, build-up → reveal |
| Review / ads | freeze + label, price as a keyword sticker, reverse-into-hand hook |
| Talking head | jump cuts with punch-in, keyword stickers, few transitions |
| Real estate | slow speed, keyword stickers for price and area |
| Event / MV | beat cuts, flash, blink, speed ramps |

## Library first

- `bashcut library list --kind effect-preset` (also `transition-preset`, `sticker`). Built-ins: `ken-burns-in`,
  `ken-burns-out`, `zoom-punch-in`, `punch-in`, `speed-ramp`, `slow-motion`; transitions `soft-dissolve`,
  `quick-whip`, `zoom-punch`; emoji stickers.
- Effect preset: `bashcut library apply ID --item CLIP --set zoom=1.4 --from F --to T --base-rev N` (every step in
  one undo; `library get ID` shows its parameters and ranges).
- Transition preset: `bashcut library apply ID --item CLIP --base-rev N` sets kind, duration, easing and its sound
  at the cut beside the clip.
- Sticker: `bashcut library place ID --at-frame F --position top-right --size 0.25 --base-rev N`.
- An effect the user liked: `bashcut library save-selection --kind effect-preset --name "Food reveal" --item CLIP`
  (or `transition-preset`, `sticker`). A correction: `library update ID --params '{...}'`, or `--as NEW_ID` for a
  built-in or plugin preset.
- A sticker or sound the library lacks: `bashcut library search "fire" --kind sticker` (or `library generate`)
  when a plugin provides it; a job, then `library add --from-result JOB:N`.

## How, in BashCut

| Effect | Make it with |
|---|---|
| Transition | `{"op":"upsertTransition","id":"t-hook","kind":"whip","from":"A","to":"B","duration":12}` (clips adjacent on one video layer; kinds: dissolve, whip, blink, zoom, spin, shutter, wipe) |
| Speed ramp | `clip speed-curve ITEM --preset hero` (montage, hero, bullet, jump-cut, flash-in, flash-out) or `--points '[[0,1],[0.5,3],[1,1]]'` |
| Constant speed | `clip speed ITEM --speed 2` (length follows; `--keep-duration` keeps it) |
| Reverse | `clip reverse ITEM` (job) |
| Freeze frame | select the clip, playhead on the frame, `ui action clip.freeze` |
| Punch-in / reframe | `setProperties` `{"reframePreset":"close","transform":{"zoom":1.3,"pan":0,"tilt":0}}` |
| Picture in picture, split moment | the second clip on an overlay layer with `transform` zoom below 1 and pan/tilt |
| Black-and-white moment | `adjustment add --look black-white` over the range |
| Pop text, labels, prices | text items with `hook-title`, `keyword-sticker`, `place-card` (`bc:captions-text`) |
| Stickers | `library place ID --position top-right --size 0.25` (image, alpha movie or emoji; see Library first) |
| Fade from/to black | `dissolve` against a black clip, or audio `fadeIn`/`fadeOut` for sound |
| Ken Burns on a photo, slow push-in | `clip motion ITEM --preset zoom-in` (also zoom-out, pan-left, pan-right, pan-up, pan-down) |
| Animated title or label | `clip motion TEXT_ITEM --preset pop-in` (fade-in-out, slide-up, zoom-punch) |
| Custom move (zoom, pan, tilt, rotation, opacity over time) | `clip motion ITEM --keyframes '{"zoom":[{"frame":0,"value":1},{"frame":45,"value":1.3,"ease":"out"}]}'` (frames from the item's start; eases linear, in, out, inOut, hold) or one key at a time: `clip keyframe ITEM --property pan --value -80 --at-frame F` |
| Zoom onto a panel of a screen recording | `clip motion ITEM --focus x,y,w,h [--focus-to x,y,w,h] [--ease out]`: the panel's rectangle in the recording's pixels (origin top left, size from `media list`); BashCut works out zoom, pan and tilt and keeps the picture's edges out of the frame. One panel per sentence. Draw the rectangle around the panel only: at zoom 1.9 a 1920 px recording showed 1010 px and a neighbouring window crept in; 2.6 isolated the panel. Confirm with `ui frame` |
| Presenter box over a screen recording | `setProperties` `{"crop": {"left": 0.2, "right": 0.2, "top": 0.1, "bottom": 0.3, "radius": 0.15}}` on the camera clip (fractions of the picture; `radius` 0.5 = circle), then `transform` zoom/pan/tilt to size and place it (zoom ~0.37 for a 9:16 camera, bottom centre). The visible part keeps its place in the picture: an uneven crop (left 0.28, right 0) left the face box off-centre to the right until pan moved it back by (left − right) / 2 × canvas width × zoom |
| Fast-forward waiting, typing, rendering | `clip speed ITEM --speed 18`, 2.4–3.6 s, no presenter or captions, one label saying what happens (a 65 s typing stretch read clearly in 3.6 s) |
| Word-by-word captions | `captions words --all --style highlight` (karaoke, reveal); see `bc:captions-text` |

Speed changes break lip sync: use them on b-roll and action, not on talking shots. Real slow motion needs
50/60/120 fps sources; slowing 30 fps footage below ~0.5× stutters.

## Not possible yet — say so and offer the alternative

- Typewriter text, counting numbers, shake, glitch, film grain.
- Segmentation (text behind a person, cut-outs), motion tracking, AI-generated transitions.

When the user needs one of these, note it as a feature request for BashCut (or a plugin action) rather than
faking it with a pre-rendered file.

## Verify

Render frames just before, inside and after each effect with `ui frame F` and read them (for motion: the first,
middle and last frame of the item); `timeline get` lists
the transitions you added. Ask the user to listen to the matching sound.