🅐 Video Preview

Every other video node in the Ace pack hands you a file path and calls it a day. 🅐 Video Preview is the one that bothers to show you what you've got. If you're using ComfyUI_AceNodes' ACE_VideoLoad at all, you want this node sitting right after it, because otherwise you're feeding a video downstream and squinting at a filename instead of the frames.

How it works

The Ace pack's video handling is deliberately dumb: ACE_VideoLoad just returns the path of a video from ComfyUI's input folder as a STRING. 🅐 Video Preview takes that string, passes it through untouched, and additionally sends the filename up to the browser so the pack's videoPreview.js can render an inline player on the node. That's the whole trick. There's no frame extraction, no ffmpeg involved at preview time - the browser plays the file directly, which is why the node feels instant.

The inputs and outputs

• video (STRING) - the file path. Feed it the output of ACE_VideoLoad (or any node that returns a real video path, like VHS's video loader).

The single output is STRING - the same path you fed in, so you can chain it mid-graph without breaking the flow. It's an output node, so it terminates a branch and shows its result in the UI.

One caveat worth knowing: this node doesn't validate anything. Feed it a real path and you get a player; feed it a random string and you get a broken widget with no error worth reading. It also expects the video to live where the JS can reach it - the normal input directory is what ACE_VideoLoad uses, and that's the safe path. If you're pointing it at a temp or output folder file, expect the preview to silently fail even though the string passes through fine.

Install

It's part of the hay86/ComfyUI_AceNodes pack - install that and you get this node for free:

cd ComfyUI/custom_nodes
git clone https://github.com/hay86/ComfyUI_AceNodes
cd ComfyUI_AceNodes
pip install -r requirements.txt

Then restart ComfyUI and search for 🅐 Video Preview under the Ace Nodes category. If you use ComfyUI Manager, just search the pack title ComfyUI_AceNodes and install from there.

Troubleshooting

The realistic failure modes here are boring. Nothing plays → check that the input string is an absolute path to a file that exists. Preview plays but the frame timing looks off → that's the file, not the node; this thing doesn't transcode anything. The one genuinely annoying thing: the pack's requirements.txt pulls in a long list of heavy packages (rembg, transformers, insightface, boto3…) that have nothing to do with video preview. You can't skip them with a normal Manager install, so installing this pack for one preview node means accepting the whole dependency list.

For actual frame-level work - grabbing individual frames, re-encoding, stitching - this node is not the tool; it's the confirmation that the tool before it worked. Pair it with VHS or a video loader that gives you real frames if that's where you're headed.