Recast 480p fails: resolution must be 768p or 1080p, priced by length

H3 Max Recast takes only two resolutions, and a 480p request is refused with H3 Max Recast resolution must be 768p or 1080p. A 10-second source costs $3.75 at 768p and $5.625 at 1080p on Sume.

Recast bills the seconds of the source video, at $0.375 per second at 768p and $0.5625 at 1080p (Sume price tool, read 2026-10-09).

Price by source length

Leave resolution out and you get 768p. That default is Sume's: fal's own default is 1080p, so a request copied from a fal example costs less on Sume when it omits the field.

A body that passes

The Video Router form takes video_url and reference_image_urls, one photo per new person. duration is the source length in seconds, rounded up, and the prompt is optional.

{
  "model": "h3-max-recast",
  "video_url": "https://example.com/source.mp4",
  "reference_image_urls": ["https://example.com/new-host.jpg"],
  "resolution": "768p",
  "duration": 10,
  "mode": "async"
}

A source that is not a whole number of seconds

duration is the inspected source length in seconds, rounded up. A 12.4-second source is sent as 13, which is $4.875 at 768p ($0.375 per second) and $7.3125 at 1080p.

Round up in code with math.ceil on the length you measured. A value under 5 or over 30 is refused, and a number shorter than the real clip makes the reserve too low.

Limits and gotchas

If the number of seconds you pass is not the real source length, the reserve is wrong. Inspect the clip first.

• Source video: 5-30 seconds, with no single shot longer than 15 seconds.
• 1-4 reference photos, one per new person.
• No aspect_ratio, image_url, end frame, reference_video_urls, reference_audio_urls, generate_audio or bitrate_mode: each is refused.
• model_params is refused.
• The output keeps the source length, motion, camera, cuts and soundtrack.