Is a 4:5 video a YouTube Short? 1080x1350 fits square or vertical

A 4:5 video, such as 1080x1350, is taller than it is wide, so it is vertical, and YouTube's Shorts page says videos with "a square or vertical aspect ratio up to three minutes in length" are categorized as Shorts (read 2026-10-09). The page does not name 4:5 specifically, so treat the classification as the page's rule applied to the shape, and confirm on your first upload. A 4:5 Timeline render at 1080x1350 for 170 seconds is ceil(170 / 60) = 3 minutes, $0.30.

The page gives one date: standard channels get the classification for videos uploaded on or after October 15, 2024. For Official Artist Channels the date is December 8, 2025.

What the page implies for each shape

The page names square, vertical and the 16:9 escape. Anything between is the page's rule applied to the shape. The table marks which entries the page names and which are inferred.

Render a 4:5 Short

Timeline output.width and output.height take even integers from 256 to 2160, so 1080x1350 is fine. Set output.fps to match the sources or omit it. The default fit is cover, which fills the frame and crops; contain and blur keep more of a source with a different shape.

The cost is by output minute, rounded up: $0.10 per minute, so a 170-second render reserves ceil(170 / 60) = 3 minutes = $0.30. The free POST /v1/timeline-1.0/plan reports billable_minutes and the estimate first. If you go to 180 seconds exactly, the price is the same, 3 minutes; 181 seconds would be over the three-minute Shorts line anyway.

{
  "audio": { "url": "https://media.sume.com/artifacts/artf_demo/vo.wav", "duration_seconds": 170 },
  "video": [
    { "source_url": "https://media.sume.com/artifacts/artf_demo/a.mp4", "start": 0, "duration": 170 }
  ],
  "output": { "width": 1080, "height": 1350 }
}

Why pick 4:5 over 9:16

A 4:5 frame is 80% as tall as a 9:16 frame of the same width: 1350 against 1920. It reuses a feed asset made for other platforms without a crop or a blur pad, and it keeps more of a horizontal composition. The cost is that the Shorts player shows less than a full-screen vertical.

The claim rule still applies: a Short over one minute with an active copyright claim of any type is blocked globally. If you reuse music across platforms, check the track before you render a 170-second version.

Checking the result

After the render, run video inspect on the output: it returns the probe (width, height, duration) plus stills, so you can confirm 1080x1350 and the duration before you upload. Stills at the first second and the last second show whether the cover crop cut a headline or a face.

If the upload is not classified as a Short, the page's rule is the place to look first: the length must be up to three minutes and the shape square or vertical. A file of 3:01 fails on length even at 9:16, and a 1920x1080 file fails on shape.