Xiaohongshu note video: 1:1 or 9:16, 500 MB, 720p

A third-party guide to RedNote (Xiaohongshu) content specs, read on 2026-10-03, lists 9:16 or 1:1, up to 15 minutes, up to 500 MB and a 720p minimum. On Sume, pick a model whose supported_aspect_ratios includes 9:16 or 1:1 and whose supported_resolutions includes 720p, then check the file size after download.

The specs, with a caveat

These numbers come from a third-party guide, not from the platform. The guide calls 15 minutes and 500 MB technical limits and recommends 1080x1920 or higher for the feed. Confirm them in Xiaohongshu's own creator guidance before you publish.

Matching them on Sume

Sume lists supported options per model at GET /v1/videos/models. The documented seedance-2 example reports 1:1 and 9:16 among its aspect ratios and 720p among its resolutions. Pass aspect_ratio and resolution; the older size field returns 400 unsupported_parameter for every model today.

A single generation is far shorter than 15 minutes: seedance-2.5 accepts 4 to 30 seconds and most other catalog models top out at 15. A longer note is several clips joined in Timeline.

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: xhs-note-001" \
  -d '{
    "model": "seedance-2",
    "prompt": "A skincare routine on a bathroom shelf, soft morning light",
    "aspect_ratio": "1:1",
    "resolution": "720p",
    "duration": 10
  }'

Check before upload

Resolution and aspect ratio are set at request time, but file size is something you measure. Download the file, check its size and dimensions, and compare to the platform's current limit. A short 720p clip is typically far below a 500 MB cap, but verify rather than assume.

Captions for the audience

If the note has speech, burn captions with POST /v1/video-captions. Use a Hangul style for Korean speech, since Latin styles reject Hangul. Chinese caption support is not described in the captions docs, so test a short clip before committing.