15-second pre-roll ad: a Wan 3.0 clip plus a still end card

A 15-second spot is a 12-second Wan 3.0 clip, a 300-character voice line and a 3-second still end card joined in one Timeline render, for about $1.61 at 720p. The end card is a still you supply, held for the last three seconds, so the offer and logo are exact pixels instead of generated text. This post does not state any platform's ad rules; check the ad platform's own page for length and format.

Why a still end card

Video models can garble small text, and a logo must be right. Timeline holds a still as a static slot, so the last slot carries your finished end-card image at full sharpness. A motion field on stills is ignored and reported as motion_ignored.

{
  "audio": { "url": "https://media.sume.com/artifacts/artf_demo/vo.wav", "duration_seconds": 15 },
  "video": [
    { "source_url": "https://media.sume.com/artifacts/artf_demo/hero12.mp4", "start": 0, "duration": 12 },
    { "source_url": "https://media.sume.com/artifacts/artf_demo/endcard.png", "start": 12, "duration": 3,
      "fit": "contain", "transition": { "type": "fade", "duration": 0.5 } }
  ],
  "output": { "fade_out_seconds": 0.5 }
}

Cost of the spot at three resolutions

Making a 30-second cut

Wan 3.0 reaches 30 seconds in one request, so a 30-second version is one clip, not several: about $3.50 at 720p for a 27-second clip, 600 characters of voice and a 3-second end card.

Make the shorter cut first. The first five seconds carry the pitch whichever length you run, so test the opening before you pay for the longer one.

Testing hooks cheaply

The opening five seconds decide whether the spot is watched, so draft three openings at 480p before you finalize one. At 480p a 12-second Wan 3.0 clip is a fraction of the 720p price, and the voice and render costs are the same. Pick the opening, then rerun that single clip at 720p or 1080p and replace the slot URL in the render. The end card never changes, so it can be reused across every variant of the campaign.