Crop 16:9 to 9:16, 1:1, 4:5, 3:4 and 2:3: video-filter fractions

To crop a 16:9 video to another aspect ratio with Sume's video filter, send a crop op with y: 0, height: 1, and a width of the target ratio times 9/16, with x set to half of what is left over. For 9:16 that is width 0.3164 and x 0.3418; for 1:1 it is 0.5625 and 0.21875; for 4:5 it is 0.45 and 0.275.

The op takes fractions of the source frame, not pixels, so the same numbers work for 1280x720 and 3840x2160 sources. Each encode is $0.02 and the program check is free. The rules below come from the Sume video filter page, read on 2026-10-03; the arithmetic is mine.

The fraction table

The docs define crop as a rectangle in fractions of the source frame: x and y in 0 to 1, width and height in 0.05 to 1, with x + width <= 1 and y + height <= 1. For a full-height crop of a 16:9 frame, the width fraction is the target aspect ratio divided by 16/9, which is the same as multiplying by 0.5625. Centering puts x at (1 - width) / 2.

The compiler rounds the result to even pixel sizes for yuv420p, so a 1920x1080 source cropped at 0.3164 lands within a pixel of true 9:16. If you need an exact output size, set it on the timeline render that follows, where output.width and output.height are explicit.

One request

Check first. POST /v1/video-filter/check runs the same schema and source preflight as the encode and returns diagnostics instead of a 400, without creating a job or reserving credit. A program that passes can still fail on the worker for resource reasons, which comes back as a structured job error.

The encode needs an Idempotency-Key and a media.sume.com source in your workspace, so import an outside file first. The default mode is async; mode: "sync" waits up to 30 seconds.

curl -X POST https://api.sume.com/v1/video-filter \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: interview-9x16-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/interview.mp4",
    "ops": [{ "op": "crop", "x": 0.3418, "y": 0, "width": 0.3164, "height": 1 }]
  }'

When the speaker is not centered

A centered crop is wrong for a two-person interview or a speaker standing on the left third. Move x toward the subject but keep x + width at or below 1; for a 9:16 crop that means x can range from 0 to 0.6836. Pull a still first to find the subject: the video frames route returns an exact frame at a time, and inspect returns up to 24 stills.

Five ratios from one interview is five encodes, or $0.10 in total. If a single clip has to feed all five placements, that is cheaper than re-shooting, and cheaper than generating new video. If the clip is already vertical and only needs a safe margin, a timeline fit of blur or cover handles it without a crop job.

• Width fraction for a full-height crop = target ratio x 0.5625.
• Centered x = (1 - width) / 2.
• Maximum x = 1 - width.
• Minimum width and height fraction: 0.05.