Comflowy Preview Video

This is the least glamorous node in the Comflowy pack, and you'll hit it the moment you try to do video. The README is blunt about it: the Hailuo and Kling nodes "require the Comflowy Preview Video node to be used." It's the video equivalent of ComfyUI's built-in Preview Image - it exists so the generated video actually shows up in your UI instead of vanishing into a file path.

What it does

The pack's video generators (Comflowy_Hailuo, Comflowy_Kling, Comflowy_Luma) return a VIDEO - which, under the hood, is a local path to an mp4 the node downloaded into ComfyUI's output directory. This node takes that VIDEO and renders it in the graph. There's no processing, no transcoding, nothing clever. It's a display node.

• Input: video (VIDEO)
• Outputs: none. It's an output node; it terminates that branch of your workflow.

Behind the scenes the pack adds a little front-end behavior: right-click the node and you get "Open preview" and "Save preview" options, which is a genuinely handy way to grab the finished clip without hunting through your output folder.

The only troubleshooting you need

The node checks whether the video file actually exists before it tries to show it. If it doesn't, you get a placeholder - an error.mp4 - instead of your clip. Nine times out of ten that means the generating node failed upstream: a dead network connection to app.comflowy.com, a spent credit balance, or an expired API key. The video generators are generous about swallowing errors and returning a dummy path, so a preview that shows nothing useful is your signal to go look at the generating node's console output, not to blame this one.

There's no scenario where you fix this node itself. If your video preview is blank, the problem happened before it.

Install

It ships with the Comflowy pack, so you don't install it separately. Grab the pack via ComfyUI Manager (search "Comflowy's Custom Nodes") or:

cd ComfyUI/custom_nodes
git clone https://github.com/6174/comflowy-nodes

Restart, set your API key with the Comflowy Set API Key node, and wire this guy onto the end of your Hailuo or Kling branch. That's the whole trick. It's boring on purpose - the one node in the pack that never costs you credits, because it never calls an API.