MiniMax H3 • Replace Video Stream (deprecated)

"Replace Video Stream (deprecated)" - the name is the whole story. This is the legacy alias for swapping the video half of an H3 AV latent, kept alive purely so older saved workflows don't fail to load. The node's own description is the instruction manual: use "Replace Stream" for new graphs, with stream=video. If you're building something fresh, do that. If you opened an old graph and this node appeared, here's what it's doing.

What it does

Identical behavior to Replace Stream with stream=video:

• av_latent - the H3 AV latent whose video stream you're replacing.
• replacement - the new video latent, from Encode Video Stream.
• fit_mode (strict / crop_pad) - strict requires matching geometry and errors otherwise; crop_pad center-crops/pads spatially.
• alignment (start / end / center) - used with crop_pad to position the replacement in time.
• denoise (default 0) - 0 keeps the replacement exactly; 1 fully regenerates it.

One output: the modified av_latent. The audio stream is untouched - that's the point of per-stream replacement.

When this node shows up

Backward compatibility is a real obligation in ComfyUI: people share graphs, and a graph with a missing node is a red box with a dead end. The pack author registered these legacy classes (Replace Video and Replace Audio as subclasses of Replace Stream) so old saved graphs deserialize cleanly. That's the same reason the class names still carry the old MiniMaxH3LatentLab prefix even though the pack is now called LongMedia. The continuity is intentional.

The cost of that kindness: the old nodes are frozen. New features land on Replace Stream, and the deprecated ones are candidates for removal in a future release. If you're maintaining a workflow, the migration is trivial - right-click the node, replace it with Replace Stream, set stream=video, done.

Install

Ships in ComfyUI-MiniMax-H3-LongMedia. Manager search "MiniMax-H3-LongMedia", or:

cd ComfyUI/custom_nodes
git clone https://github.com/vizart-vj/ComfyUI-MiniMax-H3-LongMedia

restart, with the H3 weights + VAEs available (MiniMaxAI/MiniMax-H3, ~42.5 GB, community license excludes US/EU/UK/Korea).

Troubleshooting

Since this is legacy code, the usual failure is a workflow that depends on an old interaction you can no longer see. If the replaced video isn't appearing in output, check the denoise level and whether a downstream sampler is regenerating the video stream (a video_mode=transform or auto setting can). And if you're touching this node at all in a new graph, take the two minutes to migrate to Replace Stream - you'll get the same function with the deprecation notice gone, and you won't be the one holding a graph hostage to a node that might disappear.