Kling 4.0 21:9 ultrawide: check Sume's aspect ratios
Kling 4.0 supports 21:9 output. Sume documents 21:9 as a ratio, but each model lists its own supported_aspect_ratios, so read them before sending.
Kling's post says Kling 4.0 supports 21:9 ultrawide output. Sume lists 21:9 among its documented aspect ratios, but each model advertises only a subset in supported_aspect_ratios, so read that field for your model before you send aspect_ratio: "21:9".
What does Kling claim?
One line in the 4.0 vs 3.0 post: Kling 4.0 also supports 21:9 ultrawide output for more cinematic compositions. The post does not list per-resolution limits for it in the passage read.
Which sizing fields does Sume use?
| Field | Behavior |
|---|---|
aspect_ratio | Documented ratios include 16:9, 9:16, 1:1, 21:9 (ultra-wide) and 9:21; models advertise a subset |
resolution | Subset advertised in supported_resolutions |
size | Rejected on v1: every v1 model reports supported_sizes: null |
How do I check one model for 21:9?
Read the model entry from the models endpoint and look for 21:9 in supported_aspect_ratios. If it is absent, pick a listed ratio instead. For an example of a model with a wide range, see MiniMax H3 aspect ratios.
Can I send exact pixel dimensions instead?
No. The docs say size returns 400 unsupported_parameter on v1; use resolution plus aspect_ratio. See the video docs.
Sources
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