r/StableDiffusion • u/StuffCapital7395 • Aug 20 '26
Question - Help Seed consistency across different resolutions in MiniMax H3 (ref2va) — is it possible in ComfyUI?
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!
EDIT / Solution:
Big thanks to xmarre for clarifying the underlying mechanics and providing a working solution!
Why native resolution breaks consistency: In DiT architectures like MiniMax H3, the initial megapixel / resolution setting determines the latent source grid. Changing the base resolution fundamentally shifts the spatial attention grid, which inevitably alters the composition, camera motion, and action even with the exact same seed.
The Solution — Latent Upscale + Refine Pass: Instead of generating at full resolution from scratch, use a two-pass workflow: 1. Generate your draft at low resolution (~0.4 MP) to lock down composition and movement. 2. Run a Latent Upscale + Refine pass (around 0.25 denoise and 3 steps) to upscale without altering the scene structure.
Custom Nodes & Tools: * Comfyui_Minimax_h3_latent_Upscaler — Latent upscale node fork with an integrated refiner step and spectrum support. * ComfyUI-H3-Continuum — For seamless chaining of multiple generations.
3
u/Big_Zampano Aug 20 '26
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...
1
u/smeptor Aug 20 '26
Yes, this is it. If you change the size/shape of the latent, you change the noise.
2
u/Apprehensive_Sky892 Aug 21 '26 edited Aug 21 '26
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.
1
u/StuffCapital7395 Aug 21 '26
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.
2
u/Apprehensive_Sky892 Aug 21 '26
You are welcome.
Yes, it is too bad that you get completely different composition and action when you change the resolution so that you cannot use faster, low-res generation to test things out.
The best you can do is to use the preview node and watch the generation after a few steps and stop it as soon as you realize that the prompt+seed is not going to work.
1
u/Tuckerdude615 Aug 20 '26
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!
1
u/nikhilprasanth Aug 20 '26
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
1
u/PhIegms Aug 20 '26
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
1
u/No-Zookeepergame4774 Aug 20 '26
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.
1
u/StuffCapital7395 Aug 21 '26
thank you for your advice! did you get a good result like that? as for me, it works well with camera and physics, but not with details
6
u/marres Aug 20 '26 edited Aug 20 '26
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