Seedance 2.5 vs Omni Flash at 5 and 10 s, 720p 9:16: a 4.6x gap

Both Seedance 2.5 and Gemini Omni Flash 1.1 are on Sume, and both can make a 10-second 9:16 clip at 720p. They are priced very differently because Seedance bills by video token and Omni bills by second.

The numbers

How the token price works

A Seedance token count is width x height x seconds x 24 / 1024. At 720x1280 that is 21,600 tokens per second, so a 10-second clip is 216,000 tokens. The price scales with pixels, so a 16:9 720p clip has a slightly different token count than a 9:16 one; check pricing_skus from GET /v1/videos/models and the pixel size before you budget.

Omni Flash has a flat rate per second at each resolution: $0.125 at 720p and $0.1875 at 1080p billed, against Seedance 2.5's $0.5778 per second at 720p 9:16.

What the gap buys

Seedance 2.5 runs 4 to 30 seconds, so it is the choice when you need more than Omni's 10-second ceiling in one request. Omni Flash always generates native audio and takes up to 10 reference images and 3 short clips; for Seedance 2.5's reference inputs, read supported_input_references in its GET /v1/videos/models entry. Under 10 seconds with a vertical frame, Omni is the lower-cost route, and Seedance is worth the extra only for a specific look you have tested yourself.