Open-source ComfyUI workflow renders 60-second AI videos in one pass with keystone+capstone windows
roychodraws · reddit · 2026-10-31
A Reddit user open-sourced Clowntext Hybrid Windows, a ComfyUI node suite built on kijai's MiniMax H3 context windows (ComfyUI PR #17425) and the Rolling Diffusion paper, for long-form video generation without quality decay:
- Instead of chaining clips, the whole video renders in one pass using overlapping windows, with memory capped at a single window.
- Keystone + capstone: window 1's finished first frame (keystone) and final single-frame latent (capstone) are locked into the first and back slots of every later window; each window renders switchstep steps independently, then rolls back to a snapshot for a blended finish across the full video.
- In a same-seed 60-second / 17-window test, plain hybrid windows lost heavy detail toward the end, while keystone+capstone held detail far better.
- Author reports 1 hour on an RTX 5090, with 14 extra render steps per window as the quality cost; options include per-window prompts, freenoise reuse, and sound-first rendering.
Workflows and full parameter docs are on GitHub.
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