Make a Short from a YouTube live stream: Clips, highlights, VOD trim

There are three routes from a live stream to a Short. YouTube Clips are 5 to 60 seconds and need DVR; the mobile app can save a Short highlight from a live stream; and YouTube Studio's Clips and Shorts tool picks segments from a finished video. When you hold the recording file yourself, Sume's video trim cuts any range into a new MP4. The YouTube facts are from help pages read on 2026-10-03.

Sume does not connect to a live stream or pull highlights for you. It works on a clip file, after the stream is a video.

What can YouTube do inside the product?

The pages differ in what they say, so each row cites the page it comes from.

When do you want a file instead?

YouTube's tools give you a clip on YouTube. If you need the moment in your own file, for a different platform, a branded cut or a vertical reframe, download or export the VOD you own and trim it with Sume.

Video trim reads one clip on media.sume.com in your workspace; the docs say there is no open-internet fetch and point to POST /v1/media-imports to bring a file in. You send start in seconds and exactly one of end or duration. Output is a new MP4 and the source is untouched.

Trimming the moment

Pick the range from the stream's timeline, then send it. The docs give these limits: a source up to 1800 seconds (30 minutes), a cut of 0.2 to 900 seconds, and a public price of $0.02 per job (confirm in GET /v1/catalog). A two-hour stream is therefore too long as one source; split the recording first or work on a shorter export.

precision: "exact" is the default and re-encodes for a frame-accurate cut; keyframe copies the stream and may start a little early, so read actual_start_seconds in the result. The optional output object sets width, height (256 to 2160) and fps, for exact precision only. A Idempotency-Key header is required.

curl -X POST https://api.sume.com/v1/video-trim \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: live-moment-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/stream-part-1.mp4",
    "start": 742.5,
    "duration": 45
  }'

Which route fits which goal?

Use YouTube's own Clips when the goal is to let viewers share a moment from the watch page and you are happy for it to live on YouTube. Use Studio's Clips and Shorts tool when you want a Short on your channel quickly from a finished stream, and the AI suggestions are available to you. Use the mobile highlight when you stream vertically from the app and want a first cut ready the moment you tap Finish. Use a Sume trim when you need a file: a branded cut, a vertical reframe, a version for another platform, or a batch of moments from one recording.

The routes combine. You can let YouTube find candidates, note the timestamps you like, and cut exact versions of them as files for your own edit.

Turning a wide stream clip into a Short

A stream is usually 16:9, and a Short is vertical, so trimming is only the first step. Vertical 1080x1920 render with Sume Timeline covers the reframe, and batch trimming from a spreadsheet covers a whole list of moments. Note your timestamps while you watch the replay, since Sume does not detect highlights on its own.

Upload the result as a Short and schedule it if you like; see can you schedule YouTube Shorts.