🎬 Full video walkthrough: <a target="_blank" rel="ugc" href="https://youtu.be/Rt_X0STyIZc">live demo</a># H3 Meta Batch Overlap: character swap on videos longer than 15 secondsMiniMax H3 stops at ~15 seconds. This workflow swaps a character on a video of any length, with no visible seams, and runs on an 8GB GPU.H3 Meta Batch Overlap is a ComfyUI custom node and workflow that loops a long source video through MiniMax H3 + the Character Swap LoRA, batch by batch, using the VHS Meta Batch Manager. Each batch is chained to the previous one with H3 Motion Context, so motion carries across the joins instead of jumping.Tested on an RTX 5050 8GB.---## 🔧 How it works1. Load Video splits the source into batches (Meta Batch Manager).2. H3 Meta Batch Overlap prepends the last <code>overlap</code> frames of the previous batch to the current one (first frame repeated on the first batch) and outputs a <code>batch_index</code> counter.3. H3 Motion Context uses those overlapping frames to continue the motion seamlessly.4. MiniMax H3 + Character Swap LoRA replaces the character in each batch.5. The batches are stitched back into one continuous video.## ⚙️ Key settings| Setting | Value ||---|---|| overlap | must equal Motion Context <code>context_length</code>: 5, 22, 39 or 56 || batch size | a multiple of 17 (H3 generates 17k+5 frames) || force_rate | 24 fps || Character Swap LoRA strength | 1.0 || H3 trained range | ~124–362 frames per generation |## ⚠️ LimitationAlways run the meta batch from the start. The previous batch's frames are kept in memory only, so after a ComfyUI restart mid-run, the next batch stops with an error.## 📦 RequirementsCustom nodes (clone into <code>ComfyUI/custom_nodes</code>):- [ComfyUI-H3MetaBatchOverlap](<a target="_blank" rel="ugc" href="https://github.com/shisa84/ComfyUI-H3MetaBatchOverlap">https://github.com/shisa84/ComfyUI-H3MetaBatchOverlap</a>)- [ComfyUI-H3-Motion-Context](<a target="_blank" rel="ugc" href="https://github.com/NikoDemon80/ComfyUI-H3-Motion-Context">https://github.com/NikoDemon80/ComfyUI-H3-Motion-Context</a>)- [ComfyUI-VideoHelperSuite](<a target="_blank" rel="ugc" href="https://github.com/Kosinkadink/ComfyUI-VideoHelperSuite">https://github.com/Kosinkadink/ComfyUI-VideoHelperSuite</a>)- Optional: ComfyUI-KJNodes, ComfyUI_essentialsModels:- [MiniMax H3](<a target="_blank" rel="ugc" href="https://huggingface.co/Comfy-Org/MiniMax-H3">https://huggingface.co/Comfy-Org/MiniMax-H3</a>) (ref2va diffusion model, VAEs, text encoder)- [Character Swap LoRA](<a target="_blank" rel="ugc" href="https://huggingface.co/akatz-ai/MiniMax-H3-Character-Swap-LoRA">https://huggingface.co/akatz-ai/MiniMax-H3-Character-Swap-LoRA</a>): <code>h3_character_swap_pro4500_1000.safetensors</code>## 🚀 Install1. Clone the three repos above into <code>ComfyUI/custom_nodes</code>, then restart ComfyUI.2. Download the models and the LoRA.3. Load the example workflow <code>H3_Character_Swap_Meta_Batch_Overlap.json</code> (included in the repo and attached here).4. Load your source video and your character reference, set the batch size and overlap, and queue the full meta batch.## 💡 Tips- Pick a source video with a clearly visible subject and continuous motion. That's where the seamless joins show best.- Plan the length of your source around the batch size (multiples of 17) so the last batch isn't truncated.- Disclose AI-altered content when you publish realistic swaps.Thanks to NikoDemon80 for H3 Motion Context and akatz-ai for the Character Swap LoRA.

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