MiniMax H3 Final Master Save

Every video workflow ends the same way: with the save node that refuses to behave. The Final Master Save is the opposite - it's engineered to save exactly once, at the exact right moment. It's the terminal node of the H3 Shotboard: after native segments are concatenated and the one-film upscale has run, this node encodes the final delivery movie. And if the master isn't ready yet, it deliberately saves nothing and just reports that it's waiting.

What makes it different from a plain video saver

Three deliberate behaviors. First, it's gated on master_ready: until the Native Master Load says the full film exists, this node skips the save entirely and shows you a "waiting for the remaining segments" message. No partial films, no half-renders pretending to be final.

Second, its images and audio inputs are lazy. check_lazy_status only requests the delivery branch (the LTX/Wan/RIFE output) when master_ready is true. In a graph where the upscale branch sits behind this node, that means the upscaler doesn't run during segment generation - it runs once, on the final pass, and the save happens right after it. The whole "lazy" architecture of this pack exists so that expensive branches like this only fire when the delivery stage actually needs them.

Third, it enforces a new output file. The _require_new_output_path call refuses to overwrite an existing file, and the filename includes the render id and stage label (<prefix>_<render_id>_<stage>_full.mp4). Rerun the render and you get a new take, not a clobbered one - which is the property the README's validation checklist explicitly tells you to confirm.

Inputs and outputs

Required: master_ready (BOOLEAN), master_path (the native master this delivery is based on), resolved_render_id, fps. Optional: images (lazy), audio (lazy), filename_prefix (default IAMCCS/MiniMaxH3/final), stage_label (default "delivery"). No output sockets - it's a pure output node; it returns a UI message plus an animated image preview of the saved film.

Installing it

Part of IAMCCS-nodes: ComfyUI Manager (search "IAMCCS") or git clone https://github.com/IAMCCS/IAMCCS-nodes.git into custom_nodes, restart. Needs ffmpeg for encoding; nothing else.

Gotchas

The hard failure modes are the honest ones: if master_ready is true but images or audio are missing, it raises ValueError rather than writing a broken file. And because it refuses to overwrite, a stale file with the same name means your "new" render silently saved elsewhere (or errored on the name collision) - check the output folder if you don't see an update. Wire master_path through correctly; it's used in the save's log message but the node encodes from the lazy images/audio, so those two must be the real delivery frames.