Mock Scene Video

MockSceneVideo is the video member of the mock trio in the Story JSON Nodes pack (stepan-bogatorjov/comfy_scenes_json_node). Where the real pipeline would call a video model like grok-imagine-video for each scene, this node synthesizes a short, silent clip - a flat grey frame (or your reference image) whose brightness slowly pulses - and hands it out as a real ComfyUI VIDEO object. Its whole job is to let you test the video half of the graph before any video model runs.

That matters more than it sounds, because the video side of this pack has strict naming conventions. StoryFinalCompile only finds scene clips named <scene>_<counter>.mp4, and the only way to be sure your save-and-compile chain is wired correctly is to push real clips through it. MockSceneVideo gives you those clips instantly, at the exact resolution and aspect ratio the final render will use.

How it works

It resolves dimensions from resolution (480p/720p/1080p) and aspect_ratio (9:16, 16:9, 1:1), builds duration × 24 frames, and if you've connected reference_0 or reference_1 it resizes that image as the first frame - otherwise a mid-grey base - then drifts brightness by a few percent across the clip. The frames get wrapped into a real VIDEO object via ComfyUI's comfy_api video components, so downstream it's indistinguishable from a generated clip.

Inputs and output

• resolution / aspect_ratio - set these to your production values; the compiler and any downstream save node see real dims.
• duration - 1–60 seconds of frames.
• seed - controls the drift, in case you want reproducible test clips.
• reference_0 / reference_1 - optional; if connected, the clip is built from that image (a rough preview of how the scene will look).
• prompt / model - cosmetic, logged and ignored.
• Output VIDEO - wire it into SaveVideoPassthrough, which writes scene_NNNN.mp4 to the output folder.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/stepan-bogatorjov/comfy_scenes_json_node

Restart ComfyUI (or install via Manager under "Story JSON Nodes"). No model downloads - nothing here talks to a network.

Troubleshooting

The one real requirement: a recent ComfyUI. The node builds its VIDEO object through the comfy_api module that ships with newer ComfyUI versions (the same support that defines the native VIDEO type). On an older install the import fails at load time - update ComfyUI, don't fight the node. And remember it's silent and grey by design: if you test StoryFinalCompile with these, don't judge audio mixing on the result. Use it to validate the wiring, then swap in real scene videos.