Preview Video (AI CustomURL)

Let's be upfront about this one, because the name oversells it. Preview Video (AI CustomURL) takes a file path, does some bookkeeping, and hands the path back - it doesn't actually render a video player in your node the way you'd hope. If you're picturing a thumbnail you can scrub, this isn't that, at least not in the current state of the pack. What it is is a clean terminal point for a video workflow: a node you can drop at the end, attach to your Save Video output, and use to confirm the file exists and is in the right place for ComfyUI's UI.

How it works

You give it a filepath (the absolute path from Save Video from URL, or anywhere else). It checks the file exists, normalizes it to an absolute path, and if it's outside ComfyUI's output directory it creates a symlink inside the output folder pointing at the real file - so the video shows up where ComfyUI expects output files to live. Then it logs the file size and returns the path, unchanged.

The story behind the thinness is actually interesting: the pack's own last commit is literally "Temporarily disable video UI display to test freezing issue," and the code comments say the in-node UI display was switched off to prevent freezing. So the current passthrough behavior is a deliberate, documented regression while the author figures out the hang. Worth knowing if you're on the latest version and wondering why the preview does nothing.

The input and output

Input: filepath (a string). Output: filepath - the same path, passed through. There's no processing, no conversion, no frames. It's an output node, so ComfyUI treats it as a workflow endpoint and runs it last.

Installing it

Part of the ComfyUI-AI-CustomURL pack:

cd ComfyUI/custom_nodes
git clone https://github.com/bowtiedbluefin/ComfyUI-AI-CustomURL
cd ComfyUI-AI-CustomURL
pip install -r requirements.txt

Or ComfyUI Manager → search "AI CustomURL", restart. No models, no special deps - it uses ComfyUI's folder_paths utility, which is built in.

The honest take

If you're on a workflow that chains Generate Video → Save Video → Preview Video, this node will happily sit at the end and confirm the file is where the console says it is. What it won't do yet is show you the video. For actual visual verification, your options are the file explorer, a dedicated video-preview custom node from a bigger pack, or patience while this single-author project fixes the freezing bug that got UI display disabled. Treat it as a well-behaved passthrough with nice logging, not a player - and if you need to know whether the file survived, it's perfect for exactly that.