# Skill: effect/word-carousel — "מילה מתחלפת" (Word carousel)

One word of a sentence keeps swapping — “we build apps → sites → bots” — sliding through its slot.
מילה אחת במשפט מתחלפת שוב ושוב — ״אנחנו בונים אפליקציות ← אתרים ← בוטים״ — מחליקה דרך המקום שלה.

Category: Text animations · אנימציות טקסט · a real preview: https://media.gpt.org.il/lookbook/effects/word-carousel.mp4?v=mv19exzc
Price: **60 credits per finished minute**: the render itself — 1 credit per second of 1080p output. Combined with captions, a hook or other effects: still one render, nothing more for combining.

Base URL: `https://apihub.co.il` · Auth: `Authorization: Bearer <API key>` · Docs: `/docs` (group "Video Effects")
Send `X-Tag: <job name>` on every call of one video; `GET /v1/usage?tag=<job name>` returns what it cost.
**Files are kept 24 hours** — download the finished video.

---

## 1. On its own — one call

```jsonc
POST /v1/effects/word-carousel             // x-wait-ms: 110000
{
  "video_url": "https://media.gpt.org.il/samples/sample-he.mp4",
  "start": 0.2,
  "duration": 4.6,
  "params": {
    "before": "אנחנו בונים",
    "words": [
      "אפליקציות",
      "אתרים",
      "בוטים",
      "סרטונים"
    ],
    "y": 22
  }
}
```

A normal render: `status: processing` → poll `GET /v1/executions/{id}` until `completed`, then read `output.url`.
Leave out `video_url` and the effect is drawn on a plain black canvas (9:16 unless `output.aspect_ratio` says otherwise).

When it plays: a stretch: `start` + `duration` (seconds of the finished video), or `at` (a word id) + `duration`, or `during` { from, to } (word ids).

## 2. With captions, a hook and other effects — the same render

```jsonc
POST /v1/studio/edit               // x-wait-ms: 110000
{
  "video_url": "<the video>",
  "language_code": "he",
  "captions": {
    "style": "classic"
  },
  "effects": [
    {
      "id": "word-carousel",
      "params": {
        "before": "אנחנו בונים",
        "words": [
          "אפליקציות",
          "אתרים",
          "בוטים",
          "סרטונים"
        ],
        "y": 22
      },
      "start": 0.2,
      "duration": 4.6
    }
  ],
  "audio": {
    "normalize": true
  },
  "output": {
    "aspect_ratio": "9:16",
    "resolution": "1080",
    "fit": "crop",
    "quality": "high"
  }
}
```

`effects` is a list: add more entries for more effects. The engine applies them by pipeline stage (cuts and time →
camera → grade and looks → overlays → text and captions → sound), never by their order in the list. An edit has one
`transition`, one `color` grade, one `music` bed, one `speed` and one caption style: two effects that set the same
one are refused with a message that names them.

## 3. Params

| param | default | range / options | what it does |
|---|---|---|---|
| `before` | `""` | string | The words before the slot |
| `words` | **required** | list | The words that take turns in the slot |
| `after` | `""` | string | The words after the slot |
| `size` | `6.5` | 2–30 | Letter size, % of the frame height |
| `color` | `"#FFFFFF"` | string | Text colour |
| `font` | `"Heebo"` | string | Font family — GET /v1/studio/fonts |
| `bold` | `true` | boolean | Bold |
| `y` | `30` | 2–98 | Height of the text's centre, % from the top |
| `outline` | `0` | 0–20 | An outline round the letters, % of the letter size (0 = none) |
| `outline_color` | `"#000000"` | string | The outline's colour |
| `shadow` | `true` | boolean | A soft shadow under the letters |
| `accent_color` | `"#D0F808"` | string | The slot's words |
| `hold_ms` | `900` | 300–5000 | How long each word stays, ms |
| `transition` | `"slide-up"` | `slide-up` · `flip` · `fade` | How one word gives way to the next |
| `transition_ms` | `220` | 80–800 | How long the change takes, ms |
| `loop` | `true` | boolean | Start over after the last word (false = stop on it) |

GET `/v1/effects/word-carousel` returns the same as JSON (with the full body schema). Every field has a default; numbers
outside their range are refused with the field's name.