Winter solstice class clip: dim and vignette a Wan clip for $0.02

To make a candlelit winter solstice class clip, generate a 6-second Wan 3.0 clip at 480p ($0.375), darken it with one video-filter job that dims the luma and adds a vignette ($0.02), and burn the class time on top with caption cues ($0.20). The total is $0.595 and the job needs no editing software. The filter pass is what turns a bright studio shot into an evening one.

The Farmers' Almanac (read 2026-10-11) gives the 2026 winter solstice as Monday, December 21, at 3:50 p.m. EST, the shortest day of the year in the Northern Hemisphere. A Monday-evening class on that date is an easy hook for a yoga, pottery or meditation studio.

What does the filter actually change?

Per the video filter docs (read 2026-10-11), dim multiplies the luma of the whole clip by an amount in (0, 1]. Black stays black and chroma does not change, so 0.6 gives a darker picture that is not gray. A filtergraph can then add allowlisted filters such as vignette, and the list also contains eq and colortemperature if you want to tune the tone.

It cannot add candles. Put the candles in the generation prompt ("rows of lit candles on a studio floor, dusk window light"), and use the filter only to push the mood. Dimming a clip that has no light sources will look like a dark clip, not a candlelit one.

What is the request, and can I test it for free?

Yes. POST /v1/video-filter/check runs the schema, op, allowlist and source checks, creates no job and bills nothing. A passing check can still fail on the worker, so treat the numbers below as a starting point, and look at one frame before you post. This program was not rendered for this article.

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/studio.mp4",
    "ops": [{ "op": "dim", "amount": 0.6 }],
    "filtergraph": "vignette"
  }'
# valid: true -> send the same body to /v1/video-filter
# with an Idempotency-Key header.

How do I add the class time?

Run the caption job last, on the filtered MP4. A clip with no speech needs cues or the job fails with caption_no_speech. Three cues over six seconds work: "Winter solstice" (0 to 2), "Candlelit class, Mon Dec 21, 6:30 pm" (2 to 4.5), and "Mats provided. Book by Dec 18" (4.5 to 6). Use your real time and booking rule.

What is the full bill?

Wan 3.0 is $0.0625 a second at 480p, $0.125 at 720p and $0.25 at 1080p on Sume. The filter job is listed at $0.02 and the caption job at $0.20; live prices are in GET /v1/catalog.