Stop-motion look at 12 fps: use the video filter fps filter

Run the fps filter through POST /v1/video-filter with a graph such as fps=12. Sume's Timeline output.fps only accepts 24, 25, 30 or 60, so it cannot produce a 12 fps look, but the video filter allowlist includes fps, and an encode is listed at $0.02 per job.

The trigger is Runway's Enhance Frame Rate (changelog entry dated Sep 17, 2026, read 2026-10-01), which converts video to 25, 30, 48, 60, 120 or 59.94 fps. It goes upward; the changelog does not mention a low-frame-rate look, which is the opposite request.

Why not set output.fps to 12?

The Timeline docs list output.fps as 24 | 25 | 30 | 60, and say to omit it to match the sources. Twelve is not accepted, so the Timeline path cannot give you this look.

How do I drop a clip to 12 fps?

Check the program first, then submit it. The check is free and does not need an Idempotency-Key; the encode does.

curl -X POST https://api.sume.com/v1/video-filter \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: choppy-12fps-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/clip.mp4",
    "filtergraph": "fps=12"
  }'

What about the rest of the clip?

Output inherits source geometry, frame rate and audio unless the program changes them. A graph of fps=12 changes the frame rate only, so resolution and audio stay as they were. The source can be up to 300 seconds. For the reverse problem, matching 24 and 30 fps sources inside a timeline, read 24 vs 30 fps in Timeline output.

Can I place the choppy clip in a timeline afterwards?

Yes; the docs say to drop the filter's MP4 into timeline_create video[]. Be aware of one rule in the Timeline docs: a rate that differs from a source's is met by repeating or dropping frames, reported as output_fps_resamples_sources. Expect that warning if you mix a 12 fps clip with sources at other rates.