Halloween teaser cut: Video trim start and duration, exact or keyframe

The cut

To cut a teaser from a longer shoot, call POST /v1/video-trim with video_url, start, and exactly one of end or duration. It returns a new MP4 holding only [start, end) and leaves the source untouched. Halloween 2026 is Saturday, October 31, so a Friday-night teaser for the weekend is a few clicks away.

The source must already be a media.sume.com artifact or asset in your workspace. Off-host URLs are rejected at admit, so import first with POST /v1/media-imports. An Idempotency-Key header is required.

Request

curl -sS -X POST https://api.sume.com/v1/video-trim \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: halloween-teaser-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/haunted-walkthrough.mp4",
    "start": 12,
    "duration": 10,
    "precision": "exact",
    "audio": "keep"
  }'

Exact or keyframe

precision defaults to exact, a frame-accurate re-encode. keyframe uses stream copy, so the cut may start a GOP early; re-base against actual_start_seconds in the result. The output conform (width, height, fps) works with exact only.

Then caption or assemble

A finished job's result has video_url (a new artifact), duration_seconds, actual_start_seconds, precision and optional warnings[]. Past the source the end clamps and the result warns trim_clamped_to_source. Drop the new URL into a Timeline 1.0 video[] slot with source_in 0, or caption it. There is no GET /v1/video-trim/:id; poll /v1/jobs/:id/status and read /result.