H3 Editor

A timeline video editor for MiniMax H3, inside ComfyUI. Write your shots, render them on your own GPU, and cut them together, picture and sound.

Project site: watch a cut made with it, shot by shot.

What you can do

• Write shots, not graphs. Describe what happens and what is said. The editor builds the ComfyUI graph, queues it, and shows the clip moving, with sound, while it samples.
• Keep people and places the same. Add their pictures to the cast, up to 8 per member, and write @Name in a shot or drag the member into the text. Give them a voice, or add a narrator who is only a voice.
• Join shots without a visible cut. Extend a clip forward or back, bridge two clips, or merge a join. A new clip carries on from real frames and sound of the clips it joins.
• Edit as in any editor. Trim, split, move, change speed, add transitions, flip between takes, file clips in bins, bring in your own footage and pictures, and export one video.
• Add music and narration. Lay sound files under the cut on lanes of their own, trim them and set their volume. The export mixes them in.
• Try fast, finish large. Drafts are small and quick. Finals are refined at up to 1920 pixels, with a realism LoRA for natural skin.
• Pick the model, per project or per clip. HyperFlow H3 Flash, MiniMax H3, its Turbo LoRA, Singularity, DaSiWa, 10Eros Max and PRISM are built in, and a clip can render on a different one than the rest of the project. Any other H3 checkpoint works too: pick its file, set its steps, sampler and scheduler, and save it as a preset for every project.
• Plug in speed-ups from other packs. Sparse attention, a step cache or a compile node: any installed node that takes the model and returns it can go on every render of a project, with its own settings shown in the editor.
• Let a language model write. Describe the video and it writes the shots as clips, or rewrites one clip from what you ask for. It is sent the cast's pictures, and any picture you add, such as a place or a frame of the cut, so a model that can see writes from them. It uses the model you name: a text model run by ComfyUI itself, or any OpenAI-compatible endpoint, Anthropic, Gemini or Ollama.
• Bring your LoRAs. Add LoRAs trained on MiniMax H3 to a project, or to one clip, set each one's strength, and choose whether it runs on every step or only after the first ones have set the framing.
• Generate to a recorded voice. Give a clip a recorded track, such as an approved narration, and its picture is generated to it.
• Let an agent make the video. Everything the editor does is an HTTP call, and an agent skill teaches the whole workflow.
• RefMods, if you use them. With the ComfyUI-MiniMaxH3Mod pack installed, a cast member can carry a RefMod, and the editor can make one from the member's pictures. This is the one optional extra that needs another custom node pack.

Everything else needs no other custom node pack.

Quick start

1. Install

You need a recent ComfyUI with its built-in MiniMax H3 support: 0.43 or newer. The pack is tested on 0.44. In ComfyUI's custom_nodes folder:

git clone https://github.com/igorls/comfyui-h3-editor

pip install -r comfyui-h3-editor/requirements.txt

On the Windows portable build, run the second step as ..\python_embeded\python.exe -m pip install -r comfyui-h3-editor\requirements.txt. The requirements bring ffmpeg, for importing and exporting video, and the gguf reader for HyperFlow's GGUF models.

Restart ComfyUI. H3 Editor appears in the sidebar.

2. Download the models

The pack does not download models. These are the ones a first video needs, about 54 GB:

HyperFlow's model page recommends these INT8 files on RTX GPUs with 24 GB or more. On a smaller GPU, take its GGUF files in their place, from Q8_0 at 15.2 GB down to Q3_K_M at 7.2 GB, anywhere in models/diffusion_models; see models and quality.

The text encoder and the video VAE also come in other precisions in the same repository: qwen3vl_32b_minimax_h3_int8_convrot.safetensors (25 GB) and qwen3vl_32b_minimax_h3_bf16.safetensors (48 GB), and minimax_h3_video_vae_int8_convrot.safetensors (2.6 GB). Any one of each is enough: the editor renders with what it finds, and with more than one installed you pick in the Project tab. A Qwen3-VL 4B or 8B can also stand in for the 32B text encoder, in about a third of the memory: see a smaller text encoder.

These are optional, and worth having:

Other H3 checkpoints work as well; see models and quality.

3. Make your first video

1. Open H3 Editor from the ComfyUI sidebar. It starts you on a first project.
2. In the Project tab on the right, choose the format: 16:9, 9:16 or 1:1.
3. Press New clip, write what happens in What happens, and press Render draft. The viewer shows the clip taking shape.
4. When the draft lands, press Space to play it. Not right? Change the text and render again: each render becomes another take.
5. Press Generate, then Extend forward, to carry the shot on, or add another clip.
6. Press Render final for the takes you keep, then Export. The video is saved in ComfyUI's output folder, under h3take_projects/<project>/exports.

Using the editor

The panel on the right. Select a clip and it shows the clip in tabs: Shot for what happens, the cast, sound and model, Takes for its renders, and Timeline for its speed and transition. The Project tab is always there, with the look, format, model and LoRAs that every clip shares. Esc selects nothing.

Clips and takes. Every render of a clip is a take with its own seed and the prompt that made it. Run the pointer across a take's picture to look through it, flip between takes with [ and ], keep a seed to render variations of one result, or restore a take's prompt. Rendered clips stay on disk: moving, trimming or splitting them never renders anything again. Render all drafts renders every clip that has no take yet, the ones that share a model one after another.

Cast and voices. Add in the Cast panel adds a reference picture or a voice. Choose who is in each clip, and write @Name in What happens to place them, or drag their card into the text. Write @Name in Who speaks to use their voice. A voice can be uploaded, or taken from a clip on the timeline.

The cast catalog. Press Save beside Catalog on a cast member to keep them for every project, with their pictures and voice. In another project, Add, From the catalog brings in a copy. When you change someone and save them to the catalog again, the other projects show Newer in the catalog with an Update button, or you can bring every project up to date at once from the catalog. A copy you changed in its project is never overwritten without you.

Joining shots. Select a clip on the timeline, open Generate and choose Extend forward or Extend back to generate what happens next or before. Bridge to next generates what leads from it into the following clip, landing on a short run of its first frames, and Bridge into its movement holds more of them, for a following clip that starts in mid-movement. Merge with next replaces the join between two clips with a generated crossing. These clips hold 39 real frames and their sound from the clips they join, so the cut does not show. If a clip they join changes, they are marked: render them again. An empty space between two rendered clips shows a plus that generates the bridge.

First and last frames. Give a clip an exact first or last frame by dropping a picture on it, uploading one, or using the frame at the playhead, with the buttons beside each frame in the Shot tab.

Picture to a track. A clip can hold a recorded sound, and its picture is generated to it. Extend forward carries on with the next part of the same track, so a long talking performance can be built from short shots.

Your own footage. Import brings in a video or a picture, fitted to the project's format. You can trim it, and extend or bridge from it like a