YouTube lists 1440p at 16 Mbps; Sume Timeline cannot output 2560x1440

YouTube's upload page lists 16 Mbps for 1440p SDR video, but a 1440p frame is 2560 by 1440, and Sume Timeline's output width and height must be even integers between 256 and 2160. That rules out 2560 on the long edge. The closest 16:9 render Timeline can produce is 2160 wide and 1214 tall.

What fits and what does not

The Timeline docs set the range for output.width and output.height at even integers 256 to 2160. The default is 1080x1920. For a vertical 9:16 Short, the tallest render is 1214 by 2160, because 2160 x 9 / 16 is 1215, which is odd, so it drops to 1214.

What to do instead

If a 1440p-class upload matters, there are two options. The first is a 1920x1080 render, which fits and uses the 8 Mbps row. The second is a 2160x1214 render, which carries more pixels than 1080p but is still not YouTube's 1440p tier, so do not describe it that way.

Model output does not change this. The video generation docs list 480p, 720p and 1080p for Seedance 2.5, and Timeline only assembles clips. Scaling a 1080p clip up to 1214 tall adds no detail.

Size at the recommended rate

At 16 Mbps, a three-minute video would be 360 MB (16 x 180 / 8), our arithmetic. The same length at 8 Mbps is 180 MB. Since Sume's docs do not expose a bitrate, you cannot ask Timeline to hit either number.

What Sume does not do

Sume does not render above 2160 on an edge, and it does not set bitrate or upload to YouTube. If your master already is 2560x1440, keep that file out of Timeline and upload it directly.

To decide quickly, weigh the cost of the extra pixels: the 1080p row is 8 Mbps, half of the 1440p row's 16 Mbps, so the file is half the size. If you truly need the extra pixels, the source has to be made outside Timeline and uploaded as is, since Timeline's job is assembling clips, not producing higher resolutions.