4:5 AI video: HappyHorse lists it, Sume's rows do not. Crop instead.

Alibaba's HappyHorse text-to-video API reference lists nine aspect ratios, including 4:5 for the feed. The Sume rows for Omni, Kling and the MiniMax H3 pair do not list 4:5, and Sume does not list a HappyHorse id, so for a 4:5 feed video the Sume route is to generate in a nearby ratio (3:4 on H3, or 1:1 on H3 and Kling) and crop.

Alibaba's list was read on 2026-10-07 from the HappyHorse text-to-video API reference; the Sume lists are from its Video Router docs and video docs.

Who lists which ratio

Sume's general docs name 9:21 as a ratio a model may accept, but none of the four rows above lists it. H3 also lists an adaptive value, which the table leaves out.

The crop route to 4:5

A 4:5 frame is 0.8 as wide as it is tall. From a 3:4 clip (0.75) you keep full width and trim a little height; from a 1:1 clip you keep full height and trim 20 percent of the width. Both lose little of the picture, which is why the nearby ratio is the better source than 16:9 or 9:16.

Doing it on Sume

Sume's Video filter page describes a crop operation on one Sume-hosted clip that returns a new MP4. Read the page for the exact request shape; its unbilled check endpoint lets you validate a program before you submit.

• Generate on minimax-h3 at 768p in 3:4 (5 to 15 seconds) and crop the height.
• Or generate on kling-3 in 1:1 and crop the width.
• Frame the subject centrally in the prompt, since a crop removes edge content.
• Preview one frame at 4:5 before you render a batch.

When the ratio matters more than the model

If a platform's feed placement depends on 4:5 and you cannot accept a crop, that is a reason to use a model that lists the ratio natively. HappyHorse documents it; Sume's current rows do not.

A framing checklist before you crop

A crop is only clean if the picture was composed for it. Because the crop trims the edges, anything you need must sit in the middle band of the frame. Write that into the prompt: name the subject, say it is centered, and avoid text or logos near the borders, since those are what a trim removes first.

Check the 1:1 route first if your subject is tall and narrow, such as a person standing or a bottle, because trimming 20 percent of the width costs little there. Choose 3:4 on H3 if the subject is wide, since that route trims only a sliver of height.

• Centered subject, empty edges.
• No captions burned into the generation; add them after the crop.
• One test frame at 4:5 before the batch.