Video Compare

This is a pure preview node - it has zero outputs, and that's by design. It exists so you can drop two videos side by side inside a draggable comparison slider directly in the ComfyUI canvas, without exporting anything or opening a separate video player. Before/after an edit, two different encode settings, two model outputs - anywhere you'd otherwise be alt-tabbing between two video files, this puts them in one view with a divider you drag across.

How it works

Per the pack's own README, you get a slider control and a draggable divider line down the middle: drag it and you're comparing the two videos at whatever split point you land on. It supports both URLs and local video files, can update a video's URL dynamically inside the preview, and - usefully - automatically resolves ComfyUI's own input/output folder conventions, so you don't need to hand a full absolute path to a file ComfyUI already knows about.

All four of its inputs are optional, and they come in two flavors: video_a_url_or_filepath/video_b_url_or_filepath (plain strings - paste a path or URL directly) and video_a/video_b (a proper VIDEO-typed socket you can wire from an upstream node). You can mix and match - paste one directly, wire the other from a generation node upstream. There are zero required inputs, since you can fill in either the string pair, the VIDEO pair, or both, depending on what's convenient.

Because the node has no outputs at all, it's a dead end in your graph by design - don't expect to chain anything after it. It's there to be looked at, not to feed the next step.

Installing it

ComfyUI Manager: search ComfyUI-KYNode, install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/yorkane/ComfyUI-KYNode

Restart ComfyUI. No external binaries needed for the comparison UI itself - the README notes a separate "Video File Compare" variant exists for picking straight from your input/output folders via dropdown with zero upstream wiring, if you just want to eyeball two files that are already saved.

Common issues

If you wire a VIDEO object in but nothing shows, double check you actually connected the video_a/video_b sockets and not just typed a path into the string fields (or vice versa) - since both input styles exist side by side, it's easy to fill in one pair and leave the other blank, and only one pair needs to be set for the comparison to work.

Since this node depends on ComfyUI's video preview/playback in the browser rather than doing anything itself with pixels, if a video won't load, the usual browser video-codec support issues apply - an unusual codec or container that your browser can't play natively will fail to preview here the same way it would in any HTML5 video player, regardless of whether the file itself is valid.

And because there's no output, if you're trying to use this as a step in an automated pipeline rather than a manual QA check, it's the wrong node - it's built for a human looking at the canvas, not for passing a "winner" video downstream.