Crop a 5:4 monitor clip to 9:16: width 0.45 and the exact sizes

Crop a 5:4 clip (1280x1024 or 1600x1280) to 9:16 with Sume video filter by keeping the full height and setting width to 0.45, x to 0.275. The result is 576x1024 or 720x1280. Both are exactly 9:16, which is rarer than it sounds: 0.45 gives whole, even pixels for any 5:4 size whose height is a multiple of 16.

The sum

5:4 is 1.25 wide per unit of height and 9:16 is 0.5625. The ratio is 0.5625 / 1.25 = 0.45. The centred offset is (1 - 0.45) / 2 = 0.275. Because 0.45 has no repeating decimals, the six-decimal value the compiler writes is 0.450000, and the crop width is floor(iw * 0.45 / 2) * 2 pixels. That is 576 for a 1280 frame and 720 for a 1600 frame, both already even.

Where 5:4 footage comes from

Old 17 and 19 inch monitors, some kiosks and point-of-sale screens, and a few medical and industrial displays. A typical request is a vertical teaser cut from a recording of a back-office tool. Content in a 5:4 window is usually dense, so the crop removes more than half the width. Decide whether the key panel is in the middle 45 percent. If it sits left, keep width and change x to 0; if right, use 0.55.

Resize and ship

A 576x1024 clip is below a 1080x1920 delivery frame, so add a scale. You can do it in the same request with a filtergraph, which runs after the ops. Be aware of what upscaling does to small UI text: it softens it. If the source is 1600x1280 or larger, the strip is already 720 wide and the scale is gentler. For Timeline 1.0 you can also skip the scale and let a slot's fit do the work, but that is a cover fit, which may crop again.

{
  "video_url": "https://media.sume.com/artifacts/artf_demo/kiosk.mp4",
  "ops": [
    { "op": "crop", "x": 0.275, "y": 0, "width": 0.45, "height": 1 }
  ],
  "filtergraph": "scale=1080:1920"
}

Limits

The source must be 300 s or less (output_duration_exceeded otherwise). The job costs $0.02, and you can run the body through /v1/video-filter/check without charge first. Each op's width and height must be at least 0.05, and x + width must not pass 1, or the call fails with video_filter_crop_out_of_bounds.