Preview Video

Here's the thing nobody warns you about when you land on this page: the Preview Video node doesn't exist in the current version of this pack anymore. It shipped for about a year, then got deleted when the repo was reworked from ComfyUI_MiniCPM-V-2_6-int4 into the MiniCPM-V-4_5 version. If you installed the pack fresh today, you'd search for "Preview Video" in the node list and find nothing. So before you go hunting for a missing node, let's talk about what this thing actually was - because the answer is "almost nothing, and that's fine."

What it was

PreviewVideo was the video counterpart of ComfyUI's built-in PreviewImage. The MiniCPM-V pack is a wrapper around OpenBMB's MiniCPM-V multimodal LLM - you feed it a video (or image or text) and it writes a caption or answers a question, which makes it a favorite trick for auto-captioning video before an LTX or Wan pipeline. That whole loop needs you to actually see the video you're about to throw at the model, and in 2024 ComfyUI had no native video preview. So the pack shipped a tiny pair of helper nodes: LoadVideo, which picked a file from your input folder, and this one, which rendered it.

It was a leaf. is_output_node true, zero outputs, one required input - video, the video you wanted to eyeball. That's the whole schema. Nothing computed, no model loaded, nothing passed on. Its job was to make the video show up as a playable inline widget right on the graph node.

How it worked

The mechanism was unglamorous and it's worth knowing because it explains why the node died. PreviewVideo.load_video() did nothing but split the file path into basename and folder, hand them to the UI as {"ui": {"video": [name, dir]}}, and a bundled JavaScript extension (web/js/previewVideo.js) caught that onExecuted callback and injected an actual <video> element into the node with playback controls. Right-clicking gave you "Open preview" and "Save preview." Pure front-end theater, no backend brain.

Fun detail: the author copy-pasted the node's DESCRIPTION ("Load Video") straight from its sibling, and the original LoadVideo was itself lifted from another pack - the very first commit still had a stray AIFSH_DiffSynth-Studio category string in it. The pack was young.

Install

You install it the same way as the whole pack - it was never separate:

cd ComfyUI/custom_nodes
git clone https://github.com/IuvenisSapiens/ComfyUI_MiniCPM-V-2_6-int4
cd ComfyUI_MiniCPM-V-2_6-int4
pip install -r requirements.txt

Or just search minicpm in ComfyUI Manager. But honestly: don't install this pack for this node. If you have an old saved workflow that references "Preview Video" and you want it back, pin an old checkout (the node existed as PreviewVideo from August 2024 to July 2025, e.g. commit 2c45b68). Otherwise leave it buried.

What to use instead

This is the part that matters. PreviewVideo was killed in the July 2025 commit "fix LoadVideo in New ComfyUI" because modern ComfyUI grew native video support - the IO.VIDEO type and a built-in video loader with its own preview. The pack's VQA nodes (MiniCPM_VQA, MiniCPM_VQA_Polished) now take source_video directly, no LoadVideo/PreviewVideo dance required. If you're following an old tutorial that shows the two-node chain, mentally delete the first two nodes: load the video however you normally would and wire it straight into the VQA node. You lost nothing, because this node never did anything but show you what you already had.