Loop Strip — Sprite Inspector

This is the payoff node, the one that makes all the cycle-finding and centering feel like it was building toward something. Feed it your walk-cycle batches for the eight compass directions and it opens an interactive preview right in the node - you can scrub frames, flip directions, and even drop into a little WASD "minigame" where your character actually walks around a canvas at whatever FPS you set.

If you've ever had to render eight sprite sheets and then mentally stitch together "does this look like it walks?", you know how valuable that is. You see the animation move before you save a single file.

How it works

The node itself is deliberately brain-dead - that's a compliment. It has eight optional IMAGE inputs, one per direction: N, NE, E, SE, S, SW, W, NW. Each input expects a batch of frames (a walk cycle), and anything you don't connect is just skipped. It writes the frames as PNGs to ComfyUI's temp folder, then hands the file list and your fps value to a JavaScript widget that lives in the pack's web/ directory.

The widget does the real work. There's a direction slider, a speed slider, left/right arrow buttons, and two modes:

• Inspector - the classic sprite-sheet viewer. Flip through directions, scrub frames, confirm the loop looks smooth.
• Minigame (WASD) - the fun one. Your character moves around the canvas in a top-down view using the eight directional batches, cycling the walk frames as it moves. It even auto-mirrors west frames for the east directions if you only bothered to make a west-facing cycle - a genuinely thoughtful touch for people who don't want to generate all eight.

The only input is fps (1–60, default 12), which sets the playback speed. If you loaded your source with Loop Strip - Load Video, wire its fps output straight in for an honest preview.

Install

Same pack, same routine. ComfyUI Manager → search "Loop Strip" → install, or:

cd ComfyUI/custom_nodes
git clone https://github.com/serhiiyashyn-sf/comfyui-loopstrip
cd comfyui-loopstrip
pip install -r requirements.txt

Restart after. This node is why the pack ships a web/ directory at all - the preview is pure browser JS, so you need a fresh ComfyUI reload after install or the widget won't appear. Dependencies are the usual pack set (opencv-python, numpy, torch, scipy, requests).

What to know before you trust it

It's an output-only node - no image outputs, it's terminal. And nothing is saved anywhere permanent: it writes to temp and the widget draws in-browser. If you want the PNGs, save your batches through your normal save nodes; the inspector is for looking, not for producing assets.

Two practical notes. First, it only shows what you connected - a single S input gives you a one-direction preview, which is still useful for checking a loop's seam. Second, the minigame expects each direction's batch to be a walk cycle in-place (the character stays roughly centered in the frame), which is exactly what the centering nodes produce. Skip centering and the minigame becomes a character doing a moonwalk across the screen - amusing, but not a great test. Do the pipeline right and this is the most satisfying ten seconds in the whole pack.