MiniMax H3 ComfyUI workflow guide

Set up MiniMax H3 in ComfyUI in five steps

Quick answer: This guide is for first-time MiniMax H3 users setting up an official ComfyUI workflow. Update ComfyUI, place the diffusion model, text encoder, video VAE and audio VAE in their model folders, import the task JSON, verify every loader inside the collapsed subgraph, and queue a 512 × 288, 22-frame smoke test before changing settings.

1. Update ComfyUI — Use ComfyUI 0.30.0 or newer, update Manager and restart before importing the workflow.
2. Download files — Download the workflow's diffusion model, text encoder, video VAE and audio VAE.
3. Use correct folders — Keep diffusion, encoder and VAE files in their separate model directories.
4. Import JSON — Drag the official workflow into ComfyUI and select your installed filenames.
5. Run a short test — Queue a short moderate-resolution test. Once it succeeds, save that workflow as your clean baseline before adding cache, LoRAs or longer clips.

Put each file in the right folder

Use the Comfy-Org MiniMax H3 repository as the current file index. Download only the variants required by your chosen workflow.

ComfyUI/models/diffusion_models/
ComfyUI/models/text_encoders/
ComfyUI/models/vae/

Do not rename files just to match a screenshot. Open the loader dropdown and select the filename that is actually installed. If it is missing, rescan models or restart ComfyUI.

Choose T2V, I2V or R2V

Start with T2V when you only need a prompt, I2V when an image must anchor the result, and R2V when the graph needs reference media. Node and override notes on this page were checked against Comfy-Org/workflow_templates@7837633a…; record that revision with your clean copy.

Open the T2V subgraph before Queue Prompt

The outer video_minimax_h3_t2v.json canvas is intentionally small: three documentation notes, a ResolutionSelector, a SaveVideo node and one collapsed subgraph. The loaders, prompt conditioning, sampler and decoders sit inside that subgraph. Open it before the first queue, because a missing filename or red node can otherwise stay hidden.

1. Select a real installed filename in every loader; do not rely on the name saved in the JSON.
2. Set the source image or reference media before testing I2V or R2V.
3. Fix the seed while debugging so one change can be compared with the next.
4. Resolve missing nodes, reload the JSON, and restart before installing another node pack.

Source boundary: node names, connections and shipped settings above were parsed from the pinned official T2V JSON, checked August 19, 2026. See the template overview for task and file differences.

Two settings that override what the node shows

A connected input overrides the number still displayed in its widget. In the pinned official T2V JSON, width, height and length are link-driven, so the visible values on the H3 node are not necessarily the values that execute.

Resolution

The H3 node displays 1344 × 768, but the linked ResolutionSelector ships at 16:9, 0.4 megapixels and a multiple of 32. The template's own size reference maps that setting to 864 × 480. When an exact canvas matters, disconnect the width and height links and enter the dimensions directly.

Duration

The linked math node snaps duration to the model's 17-frame block grid. Five seconds becomes 124 frames, or 5.1667 seconds at 24 fps; ten seconds becomes 243 frames, or 10.125 seconds. For a benchmark or bug report, record frames and fps instead of only the rounded duration entered in the control.

Run the 512 × 288 smoke test before anything else

Queue a short diagnostic clip before your real prompt. This site's gate is 512 × 288 at 22 frames. On one RTX 3060 12GB test bench, the official T2V and I2V smoke workflows and the site's R2V smoke workflow completed in 51.8–55.6 seconds. These are three single observations, not averages or a cross-GPU ranking.

Peak VRAM stayed between 11,591 and 11,689 MiB, or about 94–95% of the card's reported capacity, while peak guest RAM stayed between 42,348 and 43,176 MiB. On this bench, the small smoke job was therefore an installation gate, not a low-memory profile. It does not establish a universal minimum for another GPU, operating system or workflow build; use the VRAM evidence and system RAM evidence before generalising.

A successful smoke test establishes only that:

• Every loader resolved to a real file and the encoder loaded as minimax.
• The graph sampled, decoded and saved one complete video.
• The audio path produced a track when that tested workflow enabled it.
• This exact machine survived this exact short run.

Save the passing JSON as a clean baseline, then change one variable per run. Treat caching and other acceleration as a separate experiment; the cache-node record compares them against an unaccelerated baseline.

Test conditions and dates

Physical GPU 0 was an RTX 3060 12GB with 12,288 MiB. The KVM guest had 16 vCPU, about 47 GiB RAM and no swap on Ubuntu 24.04; driver 580.173.02, CUDA 13.0, ComfyUI 0.31.0 at bf4c9a08…, Python 3.12.3 and PyTorch 2.13.0+cu130 were used with no third-party custom nodes, cache node, Turbo LoRA or SageAttention. Each workflow used 512 × 288, 22 frames, 24 fps, 20 steps, a fixed seed, res_multistep, simple and denoise 1. T2V and I2V were measured August 20, 2026 with native audio on; R2V was measured August 13, 2026 with audio off.

Fix the workflow before tuning quality

Model dropdown is empty

Check the folder, filename and file completion, then restart ComfyUI. A partial download may appear on disk but fail to load.

Red missing nodes

Install the exact named custom-node repository. Restart and reload the JSON before installing another pack.

OOM before step one

The text encoder or model handoff may be the problem. A lower sampler resolution cannot fix every pre-sampling OOM.

Output has no audio

Confirm the workflow includes the audio VAE and audio path. Some optimized community workflows intentionally disable audio.

Open the symptom-led troubleshooting guide.

MiniMax H3 ComfyUI questions

How do I download the official MiniMax H3 ComfyUI template JSON?

The workflows hub hosts frozen copies of the official Comfy-Org T2V, I2V and R2V JSON templates, with the pinned revision, SHA-256 and MIT notice. Choose the task first, download that JSON, and then select the model files installed on your machine.

What files and folders does MiniMax H3 ComfyUI require?

Put diffusion files in ComfyUI/models/diffusion_models, Qwen3-VL text encoders in ComfyUI/models/text_encoders, and video and audio VAE files in ComfyUI/models/vae.

Which MiniMax H3 ComfyUI template should I use for T2V, I2V or R2V?

Start with T2V if you only have a prompt. Use I2V when a source image must control composition or identity, and use R2V when the workflow needs reference media. Run a short test before enabling audio or increasing frames.

Why does the MiniMax H3 ComfyUI template output 864 × 480 instead of 1344 × 768?

The width and height on the H3 node are inputs fed by a link from the ResolutionSelector node, and a connected input overrides whatever the widget still displays. The official template ships that selector at 16:9 and 0.4 megapixels, which its own size reference maps to 864 × 480. Disconnect the two links and type the numbers into the node when a specific canvas matters.

How many frames does a 5-second MiniMax H3 ComfyUI workflow generate?

124 frames at 24 fps, which is 5.1667 seconds rather than 5. The official template converts a duration in seconds into a frame count with a math expression that snaps up to the model 17-frame block grid, so a valid length is 17k + 5. Ask for ten seconds and the same expression returns 243 frames.

Next step

Once the clean MiniMax H3 ComfyUI workflow passes its smoke test, keep that JSON unchanged and open the task-specific workflow guide before increasing resolution, duration or adding acceleration. If the clean graph fails, diagnose the loader or memory symptom first instead of tuning quality around it.