💾📹 Save Video (tmp_api.mp4/mkv/webm) ⚠️💣

The name and the double warning icon (⚠️💣) in the pack's own README are the whole story here: this isn't your "save my finished video" node. It's plumbing. It writes to a fixed, temporary filename that other tools - or other ComfyUI instances calling in over an API - can rely on finding at a known path, and it happily overwrites that file every single time it runs. If you want a video that survives past the next run, this is the wrong node.

How it works

You give it a video_path - the path to a video file that already exists somewhere on disk (this node doesn't take a video tensor or a list of images; it works with a path string). It copies that file to a fixed temp location - tmp_api.mp4, .mkv, or .webm, matching the extension of whatever you handed it - inside the output folder. The author's stated use case is synchronizing data between API calls across multiple ComfyUI instances: one instance's workflow finishes a video, drops it at this known path, and another process (or another node like the pack's "Execute Workflow" API node) picks it up from there. It's a staging file, not an archive.

Because it always writes to the same name, there's nothing to configure and nothing to organize - which is exactly the tradeoff. You get a predictable handoff path at the cost of it destroying whatever was there before.

The inputs and outputs that matter

• video_path (required, string) - the path to the video you want staged. No other inputs.
• No outputs at all. This is a terminal node (is_output_node: true) - it does its file write as a side effect and the graph ends there for this branch.

There's genuinely nothing else to configure. If you need something more like a normal "save my video with a name I choose," look at the pack's other save nodes - this one is deliberately narrow.

How to install it

ComfyUI Manager → search Bjornulf_custom_nodes → install → restart. Manual:

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

This node itself is just a file copy, but the pack's video tooling generally leans on opencv-python and ffmpeg-python from the shared requirements.txt - install the pack as a whole rather than trying to cherry-pick.

Common issues & troubleshooting

My previous video disappeared. That's the intended behavior, not a bug - every run overwrites tmp_api.mp4/mkv/webm unconditionally. If you need to keep results, save them somewhere else first (a normal save node, or a chosen folder) and use this node only for the handoff step, not as your final destination.

It errored saying the file doesn't exist. video_path has to point at a real file already on disk - this node doesn't render or convert anything, it just relocates a finished video. If your video is still a list of frames or a video tensor, run it through one of the pack's "images to video" nodes first to get an actual file path.

I don't understand why I'd use this over a normal save node. You probably don't need it. It exists specifically for the multi-instance / API-chaining case the author describes - two separate ComfyUI processes exchanging a file through a fixed known path. If you're just generating one video and want to keep it, use a regular video-save node instead; this one is intentionally not that.