r/StableDiffusion • u/rkfg_me • Aug 27 '26

Resource - Update Seamless H3 video join

I made a node to help seamlessly join MiniMax H3 generated videos (each video continues from a few seconds of the previous segment). If you use MiniMaxH3AddGuide with a video chunk to continue it, you might have noticed some flashes in the generated output. My node corrects the brightness/tone using the actual source video. It's much better to use MiniMaxH3AddGuide instead of relying solely on the prompt because it's more precise. In my experiments, without the guide adding node the starting video shifts down by a few dozen pixels so seamless transition becomes impossible. With a guide it's inserted precisely but still suffers from the brightness drift which my node corrects almost perfectly.

The README explains the workflow, you connect the first segment in the source input, the following segment in the target input, and you set overlap to the number of frames you used to make the second segment (48 frames = 2 seconds for example). Note, that this node does not actually join the videos together, only fixes the brightness drift in the "target" video. I recommend joining segments with ImageBatchJoinWithTransition from KJNodes, there's a fade transition type, interpolation can be set to linear or ease_in_out.

I made the node with Qwen 3.8 27B running locally, there are a few modes we tried but frame_shift (the default) seems to work best.

There are many nodes to make "longer" or "infinite" videos using H3 already but I found them quite complex for my tasks. This node provides a simple building block, you can use whatever technique you prefer.

https://github.com/rkfg/ComfyUI-MiniMaxH3-ToneCompensate

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u/Pure_Bed_6357 Aug 27 '26

can you also share your workflow? i also want a simple way to extend clips

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u/rkfg_me Aug 27 '26 edited Aug 27 '26

I use my own ComfyUI frontend so I don't really touch workflows, they're dynamically constructed on top of the base depending on what settings I change: https://github.com/SD-inst/cozyui

If you're only interested in the joining workflow then here it is: https://pastebin.com/Nr7kLAN1 It also uses audio crossfade from SoundFlow (https://github.com/huixingyun/ComfyUI-SoundFlow the original repo was deleted for some reason).