720p landscape to a TikTok 9:16 ad: a 405-wide crop misses 540x960

Crop a 16:9 clip to 9:16 and you keep about 31.6% of its width at full height. From 1920x1080 that is about 608x1080, which clears TikTok's 540x960 minimum for 9:16 ads. From 1280x720 it is 405x720, which does not. So the source resolution decides whether a crop can be an ad, before you pick any tool.

The numbers

A 9:16 strip is 9/16 of the height wide. The table is arithmetic from the page's minimum, not output from a Sume job.

Check the crop for free

Sume's video filter has a crop op with x, y, width and height as fractions of the source, and a /v1/video-filter/check route that validates the program without creating a job, reserving credits or using the encoder. The encode itself is $0.02 per job in the doc. The check returns valid, any diagnostics and an estimate. The source must be a media.sume.com clip of up to 300 seconds, so import first.

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/wide.mp4","ops":[{"op":"crop","x":0.3418,"y":0,"width":0.3164,"height":1}]}'

Choosing the source tier first

Work backwards from the minimum. If the final ad must be at least 540x960 and you plan to crop a 16:9 source, the source needs to be at least 960 pixels tall, which in practice means 1080p. A 720p source cannot reach it by cropping alone, since the crop only removes pixels.

That changes the generation request. If you will crop later, ask the model for 1080p, and check which rows offer it: Seedance 2.5, Wan 3.0, Kling 3 and Gemini Omni Flash 1.1 list 1080p in the Video Router doc. Better still, if every Sume row you would use lists 9:16, request 9:16 directly and skip the crop.

The crop is useful for footage you did not generate, such as a recorded demo. There the source is fixed, and the table tells you quickly whether a vertical ad can come out of it at all.

When to regenerate instead

The check proves the program is valid, not that the result is big enough; compute the size yourself first, as in the table. If your source is 720p, regenerating at 9:16 with the model's own tier is cleaner than cropping and upscaling. The reframe guide compares the options, and a crop also drops 68% of the frame, so a subject at the edge may be lost.