LTX-2.5 48 fps option: conform frame rate on Sume

LTX-2.5 runs at 24 or 25 fps as standard, with 48 or 50 fps as an option, according to the launch summary. On Sume you do not pick a frame rate at generation time; you conform it afterwards with Timeline 1.0's output.fps, which accepts 24, 25, 30 or 60.

What the launch summary says

The same page describes native multi-shot output in one pass and a new diffusion video decoder. I am only relying on the frame rate and multi-shot points here.

What Sume exposes

Each entry in GET /v1/videos/models lists resolutions, aspect ratios, durations, frame image and reference support, audio and seed. There is no frame-rate field, so there is nothing to set per request on POST /v1/videos.

Conform a clip

Timeline needs an audio spine with a declared length and Sume-hosted clips. Import first, then render one slot. For a silent clip, use audio.mode: "silence".

curl -X POST https://api.sume.com/v1/timeline-1.0/render \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: conform-001" \
  -d '{
    "audio": { "mode": "silence", "duration_seconds": 8 },
    "video": [{ "source_url": "https://media.sume.com/artifacts/artf_demo/clip.mp4", "start": 0, "duration": 8 }],
    "output": { "fps": 24 }
  }'

The catch

A rate that differs from the source's is met by repeating or dropping frames, so motion can judder, and the job reports output_fps_resamples_sources. That means a 48 fps source forced to 24 or 30 is decimated, and 48 cannot be requested at all because 60 is the nearest option. Public rate is $0.10 per ceil output minute; confirm live in GET /v1/catalog.