Encode Video Stream

Encode Video Stream is the pack's strangest node, because unlike its siblings it doesn't just return a fake string - it actually crashes. This is from ComfyUI Core Video Nodes (Immac/ComfyUI-CoreVideoMocks), the pack GitHub describes as "A set of mock nodes for RFC purposes," and the crash is a real bug in the shipped source, not a rumor.

Here's what happens. The node declares three inputs - images (IMAGE), codec (a DICT, the thing the AV1/VP9 codec nodes emit), and frames_per_second (FLOAT, default 30, min 1, max 120, tooltip "Frames per second for the encoded video."). But the underlying function is written to accept four arguments: images, codec, bitrate, frames_per_second. There is no bitrate input anywhere in the schema. When ComfyUI executes the node, it calls the function with exactly the three inputs you provided, Python raises TypeError for the missing bitrate, and the node dies with a red error. The one case where the mock doesn't pretend - it just breaks.

Why this is instructive

The inputs themselves are a perfectly sensible encoder API. images is where your decoded frame batch goes in. codec is the quality-bearing codec object from the factory nodes - structured options instead of text, which was the good idea we covered in the AV1 Codec article. frames_per_second is the output timing. Wire a real frame batch into a node like this and you'd have an encoder. Wire it into this one and you get a crash, because the node's function signature and its declared inputs stopped agreeing somewhere in the author's drafting.

It's also a nice object lesson in why the pack stays a mock: a spec that was never actually run end-to-end. Even the mock's own internal wiring was never smoke-tested.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/Immac/ComfyUI-CoreVideoMocks

Restart ComfyUI. No pip packages, no models, no ffmpeg - pure Python on ComfyUI's own folder_paths, or grab it via ComfyUI Manager ("ComfyUI Core Video Nodes").

The bottom line

If you're here because this node threw an error in a workflow you imported: that's expected, and it's not your fault. Uninstall, or just replace it with real encoding via VideoHelperSuite (VHS) or ffmpeg. The pack has two GitHub stars and no community discussion; it's an RFC sketch for future core video nodes. If you want to study what a clean encoder interface could look like, read the input schema - just don't expect it to run.