Crop 2560x1080 ultrawide to 16:9: video filter width 0.75

To crop a 2560x1080 ultrawide clip to 16:9, send one Sume video filter crop op with x: 0.125, y: 0, width: 0.75, height: 1. The result is 1920x1080, an exact 16:9 frame, taken from the middle of the picture.

The crop op takes fractions of the source frame, not pixels, so the program does not need to know the size. The video filter docs, read 2026-10-05, say x and y are in 0 to 1, width and height in 0.05 to 1, and x+width and y+height must not pass 1.

The math

For a source of width W and height H, a 16:9 crop at full height needs a width of H x 16/9. At 1080 that is 1920, and 1920 / 2560 = 0.75. The two margins share the remaining 0.25, so x is 0.125. The same rule gives the fraction for any size. A 3440x1440 monitor-style clip needs 2560 / 3440 = 0.7442, since 1440 x 16/9 is 2560. A true 21:9 ratio is 16/21 = 0.7619, but real files differ, so compute from the probed width and height.

Request

curl -X POST https://api.sume.com/v1/video-filter \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: crop-169-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/wide.mp4",
    "ops": [{"op": "crop", "x": 0.125, "y": 0, "width": 0.75, "height": 1}]
  }'

Rounding and a free check

The compiler rounds each value down to even pixels for yuv420p, using floor(value / 2) x 2. Pick fractions that land on even numbers, as 0.75 and 0.125 do at 2560 wide. Run POST /v1/video-filter/check first. It is unbilled, validates the program, and returns the compiled filter names. The encode costs $0.02, and the source must be 300 seconds or shorter.

The output keeps the source frame rate and audio unless the program changes them.