---
title: "Make a 480p MP4 of one beat's words."
method: POST
path: "/trailers/{jobId}/beats/{beatIndex}/text-preview/render"
tags: ["Trailer"]
---

# Make a 480p MP4 of one beat's words.

`POST /trailers/{jobId}/beats/{beatIndex}/text-preview/render`

## Request

- Base URL: `https://docs.sleeperhit.studio/api/v1`
- URL: `https://docs.sleeperhit.studio/api/v1/trailers/{jobId}/beats/{beatIndex}/text-preview/render`
- Auth: HTTP bearer

Free: a 480p MP4 of the text preview's window — the trailer master's own composition over the beat and a second of each neighbour — made once for exactly these words and this picture and kept. `status: ready` carries `mp4Url`; `rendering` means it is being made (about a minute): ask again for its link. Requires `Idempotency-Key`. Scope: `story:read`.

## Headers

- `Idempotency-Key` string, required

## Response `200`

The MP4's link, or that it is being made.

- TrailerTextPreviewRender: A beat's 480p preview MP4: its url once made, else that it is being made. Free.
  - `beatIndex` integer, required
  - `beatNumber` integer, required
  - `status` 'ready' | 'rendering', required
  - `mp4Url` string, nullable, required
  - `window` TrailerTextPreviewWindow, required: What a preview plays, in seconds of the master: the beat, and a second of each neighbour.
    - `fromSeconds` number, required
    - `toSeconds` number, required
    - `beatFromSeconds` number, required
    - `beatToSeconds` number, required
  - `credits` 0, required
  - `message` string, required

## Other responses

- `401`: Missing, malformed, revoked, or expired API key.
- `403`: API key is valid but lacks the scope, is blocked by IP allowlist, or the account is disabled.
- `404`: The named project or source does not exist or is owned by another account.
- `409`: The trailer exists and the request is well-formed, but the trailer, its beat, its cast or its plates are not in a state that allows it (`trailer_state_invalid`), and nothing was reserved: a plan approved outside draft, a take chosen or a beat rendered outside review/complete, an export before the finish, a finish while a call has no selected take, a narrated cut with no narrator, a render the compile blocked, or a finish while the master failed its video coverage (`trailer_video_coverage_failed`, with `details.videoCoverage`). `details.refusal` is `{ code, action, fix }` (see TrailerRefusalDetails): `action` is what unblocks it — `recast_figure`, `add_signature_items`, `recast_voice` or `remake_location_plate` — and `fix` names the MCP tool and CLI command that take it; `details.blocked[]` lists every beat a blocked compile could not render. The identical request succeeds once the trailer is put right.
- `429`: Rate limit for this API key + IP + route family was exceeded.
- `500`: The API failed unexpectedly. Safe to retry with the same Idempotency-Key.

## Changes

- **2026-10-20** `4534f5d25540`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/sleeperhit/apis/sleeper-hit-studio-story-api/changes/trailers/:jobId/beats/:beatIndex/text-preview/render/post.md)

---

[API](https://skmtc.dev/sleeperhit/apis/sleeper-hit-studio-story-api.md) · [All operations](https://skmtc.dev/sleeperhit/apis/sleeper-hit-studio-story-api/llms.txt) · [OpenAPI document](https://skmtc.dev/sleeperhit/apis/sleeper-hit-studio-story-api/revisions/4534f5d25540?raw)