YouTube Shorts up to 3 minutes: trim a long video to fit

To fit a Short, cut the clip to 180 seconds or less with POST /v1/video-trim (start plus duration: 180) and keep the frame square or vertical. YouTube's help page says Shorts can be up to three minutes and need "a square or vertical aspect ratio".

What does YouTube's page require?

Two things are quoted: the three-minute ceiling and the shape. For long-form videos, the page says to use a wider aspect ratio such as 16:9.

How do I cut a long video to 180 seconds?

Video trim takes start and exactly one of end or duration, and returns a new MP4 with only that range; the source is untouched. The source can be up to 1800 seconds. The default precision is exact, a frame-accurate re-encode; keyframe copies the stream and can start a GOP early, so read actual_start_seconds.

curl -X POST https://api.sume.com/v1/video-trim \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: short-cut-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/long.mp4",
    "start": 30,
    "duration": 180
  }'

What if the source is horizontal?

Then the cut alone will not make a Short. Crop it with https://docs.sume.com/models/video-filter or render a vertical frame with Timeline 1.0, whose default output is 1080x1920 and whose fit can be cover, contain, stretch or blur. See convert horizontal video to vertical.

How do I check the result?

Poll GET /v1/jobs/:id/status, then GET /v1/jobs/:id/result; the result carries video_url and duration_seconds. Compare that number with 180 before you upload. Sume does not upload to YouTube for you.

What are the common mistakes?

Most failed cuts come from a small set of range errors, and each has a stable code in the trim docs. Learning them saves a debugging round.

• Sending both end and duration returns video_trim_range_conflict; send exactly one.
• Sending neither returns video_trim_range_required.
• An end that is not after start, or a range over 900 seconds, returns video_trim_range_empty.
• An end past the source clamps and the result warns trim_clamped_to_source.
• A source over 1800 seconds fails as source_duration_exceeded.

Does audio survive the cut?

By default yes: audio is keep, and an exact cut remuxes the kept audio as AAC. Pass audio: "drop" if the Short will get its own sound. The output is an MP4 encoded with libx264 and yuv420p on the exact path, priced at $0.02 per job.