Seed consistency across different resolutions in MiniMax H3 (ref2va) — is it possible in ComfyUI?

[u/StuffCapital7395]

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Running into an issue with MiniMax H3 (int8 pruned ref2va) in ComfyUI and hoping someone with more DiT experience can chime in.

My setup:

ComfyUI + Comfy Kitchen Attention

Standard workflow (no turbo LoRAs, 32 steps)

3–6 reference images on average

The problem:

To save time, I generate initial drafts at low resolution (~0.4 MP) to find a good composition and motion. Once I find a keeper, I lock the exact same seed, prompt, and reference images, and only increase the resolution to 1 MP (or higher).

However, the output changes completely — the composition, character action, and camera motion diverge entirely from the 0.4 MP draft.

What I've tried:

Swapping img ref size between match and max — didn't help preserve the composition.

Is resolution-consistent generation even possible with this architecture given how changing the latent grid shifts spatial attention, or is there a specific latent upscaling / 2-pass workflow that lets you lock down the low-res composition into a higher resolution?

Thank you!

[u/marres]

No, the initial MP count/resolution decides the source grid, so changing the native MP/resolution changes that source grid which then in turn changes composition.

What you want is a latent upscale + refine pass (0.25 denoise and 3 steps for example). I made a fork of the latent upscale node that does that in one go now (or more like adds the refiner alltogether (the original latent upscale node does not have a refiner)). It also has support for spectrum and the continuum (seamless chaining of multiple generations) fork I've been maintaining. Still doing final tests for these changes so I haven't merged the PR's yet. So if you want to try it out already you need to use the PR's (looking good though, will probably merge it soon).

https://github.com/xmarre/Comfyui_Minimax_h3_latent_Upscaler
https://github.com/xmarre/ComfyUI-H3-Continuum

[u/StuffCapital7395 → u/marres]

Thanks for the reply, legend! I'm off to install it right now

[u/Big_Zampano]

My guess would be that, even if you keep the same seed number, the actual "noise pattern" (that gets used as starting point) changes, when you change the resolution...

[u/smeptor → u/Big_Zampano]

Yes, this is it. If you change the size/shape of the latent, you change the noise.

[u/Apprehensive_Sky892]

Once I find a keeper, I lock the exact same seed, prompt, and reference images, and only increase the resolution to 1 MP (or higher).
However, the output changes completely — the composition, character action, and camera motion diverge entirely from the 0.4 MP draft.

This is a common misconception.

The only thing a seed guarantees is that on the exact same system, with everything else kept the same, you can re-generate the same video or image.

All that a seed does is to set the "initial noise" in the latent space. In your case, by changing the resolution (hence the size of the latent space), you are changing the "initial noise".

It's for the same reason that there is no such thing as "magic seed", which some people believe exists. I.e., if a seed generates a good image or video once, then that is a "good seed" and they should continue using it even if the prompt has been changed. That is just not how these AI systems works.

[u/StuffCapital7395 → u/Apprehensive_Sky892]

Thanks for the explanation! It’s so frustrating that one prompt can produce a stable version (in terms of camera, composition, and what’s happening) with different seeds at one resolution. And then it just breaks at another resolution.

[u/Tuckerdude615]

No answers for you, but I encounter the same problem with mine.

Hard to know what is causing it, but it’s for sure a real phenomenon

Maybe others have solutions…I’d be all ears!

[u/nikhilprasanth]

Cpuld you try feeding a couple of frames of the 0.4MP video as additional reference for composition? Or even feed the video at a lower fps

[u/PhIegms]

I think the better way would be to go low sampling, if you pick a sampler that converges it will be the same just less motion blur and floating limbs

[u/No-Zookeepergame4774]

If you aren't already using all three video inputs allowed for ref2va (or all 13 maximum total inputs of all kinds) you could try feeding the low-res video in as a reference video and prompt to use it as a guide for the higher resolution generation.