ComfyUI-PreviewVideo

Preview Video for ComfyUI

A missing companion to ComfyUI's built-in Save Video node: preview native VIDEO output directly in the graph without permanently saving every test generation.

Why this node exists

ComfyUI has Preview Image for images and Save Video for videos, but no equivalent temporary preview output for the native VIDEO type. During iteration, Save Video fills the output directory with files that were only needed for a quick look. This node provides that preview-only workflow.

Features

• Accepts ComfyUI's native VIDEO type.
• Shows a playable video preview inside the node.
• Preserves video audio.
• Supports the same automatic container/codec behavior as Save Video.
• Provides optional H.264 re-encoding and CRF control.
• Passes the original VIDEO through its output for further processing.
• Writes only to ComfyUI's temporary directory, never to output.
• Optionally embeds VHS-compatible workflow metadata in the preview video.
• Videos saved from the preview menu can restore their workflow when dragged back into ComfyUI.
• Provides a customizable filename for previews and downloaded videos.
• Shows resolution, frame count, frame rate, and duration below the preview.
• Has no third-party dependencies.

Temporary files remain eligible for ComfyUI's normal temporary-file cleanup.

Installation

ComfyUI Manager

Search for Preview Video in ComfyUI Manager and install it.

Manual

Clone this repository into ComfyUI/custom_nodes:

git clone https://github.com/elgalardi/ComfyUI-PreviewVideo.git

Restart ComfyUI, then search the node library for:

Preview Video

Usage

Connect any native VIDEO output to the node's video input. Leave format and codec on auto for the fastest and most compatible behavior. Use H.264 re-encode only when you need a specific CRF.

Leave include_workflow_metadata enabled to embed the workflow in the temporary preview. You can then right-click the preview, save the video, and drag that file back into ComfyUI to restore its workflow. This metadata format is compatible with Video Helper Suite.

Set filename to choose the downloaded video's name. Right-click the node and select Save video to download it with that exact generated name. Preview Video appends a counter and the selected container extension automatically so repeated previews do not overwrite each other.

The filename supports ComfyUI's standard text replacements. For example, preview_%date:yyyy-MM-dd% includes the generation date in the saved filename.

This is an output node, so it can execute a preview branch without requiring a Save Video node.

Compatibility

The node uses ComfyUI's versioned V3 backend API and requires ComfyUI 0.30.0 or newer. It is operating-system and GPU independent.

License

MIT