Shorts camera segments with undo vs a Sume Timeline of slots

YouTube's Shorts camera records in segments: hold Capture or tap it to start, tap again to stop, and Undo or Redo clips. The same idea in Sume is a Timeline 1.0 video[] list, where each slot is one segment with a start, a duration and optional source_in. Reorder or drop a slot and render again.

What YouTube's page says

"Get started creating YouTube Shorts" (read 2026-10-05) describes recording with Hold Capture or a tap to start and stop, adjustable duration and Undo and Redo of clips. It also lists music, filters and effects, text-to-speech and a Get feedback button on the hook and pacing.

Slots as segments

Timeline 1.0 takes 1 to 200 slots, the first at start 0 with later starts increasing, and each slot at least 0.2 seconds. An "undo" is removing a slot and re-timing the rest; a "redo" is putting it back. The plan route compiles the list for free, so you can try edits before a billed render.

{
  "audio": { "url": "https://media.sume.com/artifacts/artf_demo/vo.wav", "duration_seconds": 12 },
  "video": [
    { "source_url": "https://media.sume.com/artifacts/artf_demo/take1.mp4", "start": 0, "duration": 4 },
    { "source_url": "https://media.sume.com/artifacts/artf_demo/take2.mp4", "start": 4, "duration": 4 },
    { "source_url": "https://media.sume.com/artifacts/artf_demo/take3.mp4", "start": 8, "duration": 4 }
  ]
}

Where the in-app camera still wins

Recording live, effects and text-to-speech are in YouTube's app. Sume does not replace that. It helps when the footage already exists as files, when you want the same cut repeatable, or when you generate several clips and join them.

• Keep one JSON body per cut version.
• Use source_in to pick a different moment from the same take.
• Upload the finished MP4 from a phone or computer, as the page describes.

Cost

Timeline is $0.10 per ceil output minute in the docs, so a 12 second cut is one billed minute at that list rate. Confirm with GET /v1/catalog.