Square 1:1 AI video for YouTube Shorts: Seedance 2.0 15 s from $2.64

A square 1:1 video up to three minutes long is a YouTube Short, so a 15-second square clip from Seedance 2.0 qualifies. On Sume it costs 15 x $0.17577 = $2.63655 at 480p, 15 x $0.378 = $5.67 at 720p and 15 x $0.8505 = $12.7575 at 1080p. Seedance 2.0 is the model whose supported ratios in the Sume docs example include 1:1.

What YouTube says

YouTube's help page, read 2026-10-09, says Shorts can be up to three minutes and that a video is classified as a Short when it has a square or vertical aspect ratio. It also says a Short longer than one minute with an active copyright claim is blocked globally and cannot be monetized. A 15-second clip stays well under that one-minute line.

• Upload date rule on the page: standard channels, uploads after October 15, 2024.
• A 16:9 upload is not classified as a Short, so ratio matters more than length for a 15-second clip.

Price by resolution

Rates are provider list times 1.25, default options, read 2026-10-09. Seedance 2.0 accepts 4 to 15 s, so 15 s is its maximum. The supported_aspect_ratios list in the docs example for seedance-2 is 21:9, 16:9, 4:3, 1:1, 3:4 and 9:16; read GET /v1/videos/models for the live list of any other model before you assume it takes 1:1.

Length and ratio together

The two YouTube rules combine. A 15-second 1:1 clip is a Short because it is square and under three minutes. A 15-second 16:9 clip is not classified as a Short. If you stitch several 15-second clips into one video, a 45-second square result is still a Short, and stays below the one-minute mark where the copyright-claim rule changes.

Check the ratio on the Sume side too. The model's supported_aspect_ratios field in GET /v1/videos/models is the source of truth, and a request with an unsupported ratio fails validation. Gemini Omni Flash, for instance, lists only 16:9 and 9:16, so it cannot make a 1:1 clip.

A practical split is to render all variants of a hook at 480p, pick the winner, then rerun only that prompt at 1080p. Ten 480p drafts cost $26.37 and one 1080p final costs $12.76, for $39.13 in total, against $127.58 for ten 1080p attempts.

Request

Set aspect_ratio to 1:1 and duration to 15 on POST /v1/videos. A first-pass square at 480p costs about a fifth of the 1080p price, and the 480p to 1080p ratio is 0.17577 / 0.8505 = 0.207. Draft at 480p, then render the keeper at 720p or 1080p. For a song or voice track, upload your audio separately: Seedance 2.x accepts audio references according to the Sume docs.