Re-upload an old vertical video: is it a Short or long-form?

Per YouTube's three-minute Shorts help page, the class is set by upload date and file shape. A video uploaded on or after October 15, 2024 with a square or vertical aspect ratio and a length up to three minutes is categorised as a Short. A video uploaded before that date stays long-form. A re-upload is a new upload, so by the page's wording a vertical 2:30 file you upload today would be a Short, while the original from 2023 stays where it is.

What the page says, and for whom

The page distinguishes two channel types with different dates, and it states a Content ID rule that matters for longer Shorts.

Why a re-upload may not be what you want

Two things change when the same footage becomes a Short. First, monetisation moves to the Shorts revenue-sharing model from the Shorts feed, according to the page, instead of long-form on the watch page. Second, a Short over one minute with any active Content ID claim is blocked globally, with no channel penalty; the page says nothing changes for Shorts under a minute. If the old video has licensed music in it, a re-upload as a Short can fail where the long-form original did not.

Keeping it long-form on purpose

The page's advice is to use a wider aspect ratio such as 16:9 if you do not want a video classified as a Short. With Sume you can control that at render time: Timeline 1.0 defaults to 1080x1920 but accepts output.width and output.height as even integers between 256 and 2160, so a 1920x1080 output is a normal option. Note this is a Sume setting that I describe from the docs, not something I tested against YouTube's classifier.

Check the file before you upload

Use video inspect with frames: false. It returns the probe only, with no stills, so you can read duration and frame size and see the shape the upload will have. If the clip runs past three minutes, cut it with video trim. duration takes 0.2 to 900 seconds, so duration: 180 produces three minutes on the dot, and a Short of exactly 180 seconds is still inside the page's "up to three minutes".

{
  "video_url": "https://media.sume.com/artifacts/artf_demo/old-vertical.mp4",
  "start": 0,
  "duration": 180
}