Quality and upscale — what to pick
Two separate choices. The default is the best value, and it is not a compromise.
Quality is what the model renders. Upscale is what happens to that render afterwards. They are separate because they cost very differently: the render dominates the bill, so buying resolution at the upscaler is far cheaper than rendering it.
For a 5 and 10 second clip on Seedance 2.5:
| Route | Rendered at | Delivered | 5s | 10s |
|---|---|---|---|---|
| 480p → 4K | 480p | 3840x2160 | $0.67 | $1.33 |
| 480p → 1080p | 480p | 1920x1080 | $0.56 | $1.11 |
| 480p as rendered | 480p | 480p | $0.53 | $1.04 |
| 720p → 4K | 720p | 3840x2160 | $1.32 | $2.63 |
| 720p → 1080p | 720p | 1920x1080 | $1.21 | $2.41 |
| 720p as rendered | 720p | 720p | $1.18 | $2.34 |
| 1080p → 4K | 1080p | 3840x2160 | $3.03 | $6.03 |
| 1080p as rendered | 1080p | 1080p | $2.89 | $5.74 |
That is why the default is 480p as rendered: it delivers 3840×2160 for less than a native 1080p render costs, because the expensive part — the model — is doing less work.
When native 1080p is worth it: the upscaler infers detail that was not in the 480p render, and on fine texture, small faces and dense foliage that inference can look synthetic. A native render has no interpolated detail. You are paying several times more for that honesty.