Reframe an AI video to 9:16: regenerate, crop or fit?

Luma's Ray3.2 announcement, dated June 9, 2026, lists enhanced reframe as a feature. Sume has no tool called reframe; to get 9:16 from a clip you have three options: generate at 9:16 in the first place, crop a 16:9 clip with video filter, or fit it into a 1080×1920 Timeline render. The crop is a $0.02 encode job.

What does Luma mean by reframe?

Luma's announcement, read 2026-09-29, names "enhanced reframe" in a feature list and gives no detail in the text saved for this page. This page therefore does not describe how it works.

Should I regenerate at 9:16 instead?

If the clip is not made yet, ask for the ratio. 9:16 is a listed aspect ratio, and each model advertises the subset it accepts in supported_aspect_ratios; gemini-omni-flash-1.1 is documented as 16:9 or 9:16. A new generation composes the shot for the vertical frame, so it is the option that changes the picture, and it is a new paid job.

When is cropping the right call?

When the subject already sits in a vertical slice of the 16:9 frame. The crop op takes fractions of the source frame. A full-height 9:16 slice of a 16:9 frame is 81/256 of its width, about 0.3164, and centered it starts at about 0.3418. That is arithmetic, not a docs rule. The unbilled check route validates the program without creating a job:

curl -X POST https://api.sume.com/v1/video-filter/check \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/talk.mp4",
    "ops": [{ "op": "crop", "x": 0.3418, "y": 0, "width": 0.3164, "height": 1 }]
  }'

How do the three options compare?

Pick by what you can afford to lose: picture, edges or a rerun. The full crop and fit walkthrough is in converting horizontal video to vertical.

What must I do before either tool sees my clip?

Video filter and Timeline read only this workspace's media.sume.com files, so import the clip first with POST /v1/media-imports; both encode routes require an Idempotency-Key. The filter's check route does not. Read the video filter docs for the refusal codes.

What size is a cropped result?

The crop keeps the source's pixels, so it is smaller than the source: a 1920×1080 clip cropped to the 0.3164 slice is roughly 606×1080 (arithmetic), with sides rounded to even numbers for yuv420p. That is a 9:16 shape but not a 1080×1920 frame. If you need the full vertical frame, the Timeline route defaults to 1080×1920 and offers fit modes that place the clip in it.

A crop can fail with video_filter_crop_out_of_bounds when the rectangle leaves the frame or a side is under 0.05, and a source longer than 300 seconds fails with output_duration_exceeded. The check route surfaces the first kind before you pay.