Instagram Reel cover at 420x654 (1:1.55): crop and pull the frame

Instagram's help page recommends a Reel cover of 420px by 654px, a 1:1.55 ratio. A 9:16 frame is 1:1.78, so it is taller than the recommendation. To get a cover in the recommended shape from a 1080x1920 clip, crop 123 pixels off the top and bottom, which leaves 1080x1674, then pull the frame you want from the cropped file.

The cover size is from Reel size & aspect ratios on Instagram (read 2026-10-03). The page gives the dimensions but does not describe how the app places a cover, so treat the crop as a way to keep your key content safe, not as a documented requirement.

The arithmetic

At 1080 wide, a 1:1.55 shape is 1080 x 1674 pixels (1080 x 1.55). From a 1080x1920 frame that removes 246 pixels of height, or 123 at each edge. As fractions of the frame, the crop starts at y = 0.0641 and is 0.8719 tall. Put another way, anything that matters in the cover should stay inside the middle 87 percent of the frame's height.

Crop, then extract

Video filter takes a crop as fractions of the source frame and returns a new MP4, for $0.02 an encode. Then video frames pulls stills from the cropped clip at the times you give, up to 24 per call, as PNG if you ask for it. Both read a clip already on media.sume.com.

curl -X POST https://api.sume.com/v1/video-filter \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: cover-crop-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/reel.mp4",
    "ops": [{ "op": "crop", "x": 0, "y": 0.0641, "width": 1, "height": 0.8719 }]
  }'

Then pick the frame

When the filter job is ready, send the returned video_url to POST /v1/video-frames with at: [0.5, 1.5, 3] and format: "png". Look at the three stills at phone size and keep the one where the subject and any burned-in text are clearly inside the frame. The result is 1080x1674, so scale it to 420x654 in your design tool if you want the exact recommended size.