Five dim levels for a TikTok ad cost $0.10; the check can't preview

The free check cannot show you how a dim level looks. POST /v1/video-filter/check returns valid, diagnostics, a compiled filter list, an estimate and next_action, and its encode field says not_run. To compare five amounts by eye, such as 0.30, 0.45, 0.60, 0.75 and 0.90, you have to encode each one, at $0.02 per encode job: 5 x $0.02 = $0.10 (as of 2026-10-08). The five checks in front of them cost nothing.

Why you would dim a TikTok ad

Burned-in captions are usually white, and white text over a bright frame can be hard to read. A darker picture underneath is one fix. (TikTok's page says the separate ad caption field is shown in white in a uniform font you cannot customize; that field is not what this post dims for.) The dim op in Video filter multiplies the luma of the whole clip by an amount above 0 and up to 1. Black stays black and the chroma is unchanged, so the picture gets darker without a color shift.

What the check does and does not do

The check runs the same schema, op whitelist, filtergraph allowlist and host preflight as the encode. It creates no job, reserves no credits, boots no box and uses no encoder. It also needs no Idempotency-Key. Use it to catch the cheap mistakes: an amount of 0 or above 1, a missing media.sume.com URL, a source that is not a video.

Cheaper ways to choose

You do not need five full encodes. Video filter accepts sources up to 300 seconds, and a job costs $0.02 whatever the length. So trim a 5-second sample first (Video trim, $0.02), then run the dim candidates on the sample. That adds $0.02 to the total: $0.02 + 5 x $0.02 = $0.12, and each candidate is a short file that is quick to open. If you can eyeball the brightness with two candidates instead of five, the total drops to $0.06.

Or skip the preview. Pick 0.45, the docs example, encode it once for $0.02, and keep the original file. The filter never changes the source, so if the result is too dark you re-run from the original with a higher amount. Each retry is another $0.02, so a one-candidate-at-a-time search is no more expensive than the five at once.

After you choose

The dimmed clip is a new MP4 on media.sume.com. Put it into Timeline video slots, or burn captions on it with the caption job, which needs a public HTTPS URL. Check the finished file against the TikTok page: 540x960 or more for 9:16, up to 10 minutes, 500 MB or less, 516 kbps or more. Sume does not offer a bitrate field, so measure the file you get.

A two-step search

Binary search works well here. Encode 0.45 first. If it is still too bright, try 0.30. If it is too dark, try 0.60. Three encodes ($0.06) usually settle a level that five parallel jobs would. Judge on the target screen: a phone at arm's length shows glare that a desktop monitor hides.