Wan 3.0 smart duration and adaptive ratio vs Sume's explicit fields

QwenCloud lists smart duration and adaptive aspect ratio as Wan 3.0 features, without more detail on the changelog page. On Sume's POST /v1/videos, duration is an integer in whole seconds and aspect_ratio must be one the model advertises, so you choose both explicitly. wan-3.0 accepts 2 to 30 seconds.

For a vertical example see Wan 3 vertical 9:16 video.

What did QwenCloud list?

The changelog entry says Wan 3.0 features include audio generation, sound toggle, smart duration, and adaptive aspect ratio. It does not define the two terms there, so this post does not describe how they behave.

How do duration and ratio work on Sume?

duration is an integer, in seconds. aspect_ratio is validated against the model's list, and each model advertises the subset it accepts in supported_aspect_ratios. Durations come from supported_durations.

Does the legacy shape have adaptive ratios?

The legacy Video 1.0 shape lists auto and adaptive among its aspect_ratio values, alongside 21:9, 16:9, 4:3, 1:1, 3:4 and 9:16. That shape is validated against the Auto serving family, not against Wan, so do not read it as Wan's adaptive ratio.

What should I send for Wan?

Pick a whole-second duration between 2 and 30 and an aspect_ratio from the model's supported_aspect_ratios. Check both on GET /v1/video-router/models before the first request.