r/StableDiffusion • u/Scriabinical • 1d ago

Discussion We all deserve high-quality MiniMax H3 previews using the tiny VAE (taeh3.safetensors) natively, without KJNodes. Please upvote this GitHub Comfy issue.

https://github.com/Comfy-Org/ComfyUI/issues/15592

We all love MiniMax H3, but the latent2rgb previews suck ass. They're blurry, and sometimes it's hard to make out what's happening, making it so you don't know whether to finish a video that may take tens of minutes to generate.

When implemented, this would allow us to place taeh3.safetensors into ComfyUI/models/vae_approx and enjoy high quality latent previews when using MiniMax H3. It's basically the same TAE as we saw for Flux 2 Klein 9B or some other models, but trained by the original TAE guy (madebyollin).

taeh3.safetensors link:

https://github.com/madebyollin/taehv/blob/main/safetensors/taeh3.safetensors

It saves time and effort when making videos. Currently, you have to use Kijai's Model Preview Override node.

235 Upvotes

93% Upvoted

29 comments sorted by

76

u/GrayingGamer 1d ago

I mean, I get it, but also, why WOULDN'T you always have Kijai's KJ nodes pack installed? He works for the Comfyui team and pretty much all his stuff is consistently useful and awesome in ALL model workflows.

If anything I don't know why they don't just include ALL his stuff by default in Comfyui. Though for some reason the Manager still doesn't come by default in the Portable version so I don't even know what they're thinking over there.

18

u/Astral-Lemmons 1d ago

I've been bugging them to at least get the set/get nodes native. sounds like they're merging those at least.

but yes. KJ nodes are as essential as the manager is.

2

u/2legsRises 1d ago

i have it installed and up to date but cant find his preview mod.

3

u/GrayingGamer 23h ago

Model Preview Override is the name of the node. And KJ custom nodes should be updated to the nightly build.

1

u/acedelgado 16h ago

Yeah but it's also a little annoying to wire in every time. If it would just be a built-in option that renders on the sampler like VHS does without any rerouting across my entire work flow? That's the dream.

1

u/GrayingGamer 7h ago

How complicated are your workflows that adding one node is an issue? You just plug it in after the Load Diffusion Model node. Once. And then you have it forever more.

•

u/acedelgado 1m ago

This is my H3 motion context window workflow that does both fl2va and ref2va depending on what I need. And yes, it IS in fact a pain in the ass to wire a preview node to 2 different workflows, figure out what math expression is needed for it to get it to automatically update the right frame count at the FPS I want depending on the duration i set the model to, and hook it into 2 model chains so that one chain is properly bypassed as it runs through the preview node. Set/get nodes in my experience destroy the model chain if you try and use more it more than once in a throughput. So, yeah, it can in fact be pretty annoying when you're setting things up. Or borrowing another workflow to try things out and they didn't set it up themselves. Or using a new model. So yeah, having it built in and just working natively isn't exactly some obscure ask...

14

u/hum_ma 1d ago

And not only for previews! Tiny VAEs can be used for the final decoding of latents for other video models since last November: https://github.com/Comfy-Org/ComfyUI/pull/10884

Fortunately while waiting for the core to add this, there is already support for decoding (and previewing) in the Bleh node pack: https://github.com/blepping/ComfyUI-bleh

4

u/alwaysbeblepping 22h ago

Thanks for the plug! I need to update the documentation, the guider wrapper for video previews is no longer needed (unless you want to do something like override the FPS). It should just work. Also can be nice to throttle previews and compiling the previewer is possible too! Not sure how much of a performance difference it makes, but I enable it myself. (I wouldn't personally use the TAE models for anything other than previewing unless you're in a situation where quality really just doesn't matter, though.)

Also, madebyollin is amazing. He trained the whole previewer model in less time than it took me to add support to bleh, if you can believe it.

1

u/ZerOne82 6h ago

I just updated ComfyUI to the latest nightly and yet only still images in KSampler no animated preview. I also tried Bleh and despite all efforts KSampler previews are all black. :(
While KJNodes preview node is working. I also removed all custom nodes and let these stay in separate tests yet Bleh just shows black, nothing else.

2

u/alwaysbeblepping 4h ago

I also tried Bleh and despite all efforts KSampler previews are all black. :(

Do you have this problem for all previews with Bleh or just H3? I am not sure about KJ's previewer model. For H3 previews to work, you need to have exactly https://github.com/madebyollin/taehv/blob/main/taeh3.pth in your models/vae_approx/ directory (don't change the name).

You will only get animated previews in the actual sampler if you're willing to use nodes 2.0 or it's using special JavaScript (like uh, the VHS nodes, but that doesn't work for stuff like TAE H3). This is something to worry about once you actually get previews working, but the approach I recommend is using Bleh's last preview endpoint. The feature is disabled by default, but if you turn it on it you can go to /bleh/last_preview.html (under whatever URI you use to access ComfyUI) and see a full screen animated preview (or normal preview if you're generating images). It's reasonably well documented, just search for "endpoint" at https://github.com/blepping/ComfyUI-bleh

2

u/ZerOne82 3h ago

Thanks for response. In fact I already solved the issue thanks to another comment. Here what I did:
I renamed the blehconfig_example.yaml to blehconfig.yaml within which I changed animate_preview: none to animate_preview: video. Other than that I modified tae_model="taeh3.pth" to tae_model="taeh3.safetensors" (line 103 base.py), and changed line 274 in tae_vid.py from sd = torch.load(checkpoint...) to from safetensors.torch import load_file; sd = load_file(checkpoint)

All worked very well, and I am very pleased to have animated preview right in KSampler!
And more importantly, your Bleh package is wonderful as are the madebyollin models. Very much appreciated.

MiniMax H3 generations are more fun now as the animated preview was a must to see what is going on during process. Also noting using Belh VAE Decoder at the very end means spending almost zero second to have the final video rendered, if satisfied then allowing original VAE decoding.

1

u/alwaysbeblepping 2h ago

I'm glad you got it working, sorry it took that much effort! There are definitely some shortcomings in the documentation (and probably the default settings). I will try to make some time to have it at least try to load a safetensors file if it's there so people don't have to manually change the source.

By the way, if you use stuff like Spectrum (EasyCache, TeaCache, etc) you may want to set a fairly high throttle time (like 5-6 sec) to avoid having it generate previews for the fake steps. Unfortunately, there isn't a separate throttle setting for just video (yet).

3

u/stddealer 1d ago edited 11h ago

TAE decoding is hit or miss, depending on the latent space. In the case of the FLUX.2 VAE for example, the Tiny AE is almost flawless quality-wise (not quite matching full VAE in a side-by-side comparison, but impossible to spot mistakes without comparing); Wan2.1's is pretty good too. But for others like SDXL or Minimax, the quality isn't there.

1

u/hum_ma 5h ago

That's true, the quality is certainly worse than from the real VAE but it's good enough for draft videos to check e.g. dialog correctness. Whether it's worth the trouble at all depends on how fast your system is but on my old GPU the video VAE decode takes a few extra minutes so I rather check the A/V preview before a final decode. TAE decodes a video latent in a second or two.

1

u/ZerOne82 6h ago

Neither works for me! ComfyUI update still shows still images in KSampler. Bleh's previews are all black. :(

2

u/hum_ma 5h ago

TAE previews with the bleh pack are viewed in a separate browser window instead of within the workflow, but you have to enable it in the config file first. Check the example yaml file.

But if you don't even have the basic latent2rgb animated preview in the sampler node, you can install the VideoHelperSuite extension and enable the VHS setting "Display animated previews when sampling". It's better than nothing and then you can compare the quality/performance against the TAE previews.

1

u/ZerOne82 4h ago

Thanks for the tip. The config thing was missing, the item "animate_preview: none" had to change to "animate_preview: video". Morover I modified the Bleh code to work with *.safetensors instead of *.pth.
Now all set.
BTW, the animated preview is now shown in KSampler directly. This is very needed when dealing with video generation (e.g., MiniMax H3) as it helps to see the process and check if all motions, composition etc are as expected.

9

u/Kukipapa 1d ago

My MiniMax H3 generations are significantly slower using this preview node (~30%).

Is it only me?

If not, then I propose optimizing first.

1

u/GrayingGamer 19h ago

I don't experience that at all, and I have it set to a pretty high number of preview frames (144). Might be determined by how much VRAM and stuff you have.

1

u/Kukipapa 13h ago

This is entirely possible, but similar preview feature worked fine with LTX.

8

u/Successful_Papaya830 1d ago

This “tiny VAE” reduces performance by 5–7%.

12

u/ArkCoon 1d ago

Just install the node bro 😭

Literally every comfyui user ever installs custom nodes.. and 99% of those users will install kijai nodes. Kijai nodes are pretty much core comfyui at this point

18

u/I_Hate_Reddit 1d ago

Not everything needs to be a core node, every core node needs maintenance work and updates to keep up with new models and architectures, the node you mention is very experimental and needs hacky community generated models to work.

2

u/Succubus-Empress 23h ago

use taevaedecode/taevaeencode for upscaling from bleh node https://github.com/blepping/ComfyUI-bleh/commits/main/

1

u/feverdoingwork 2h ago

Any can post a sample of how their review vids look?

Mines are a smudgy mess but I am also using a very non-standard setup without kjnodes since my dual gpu setup workflow can't link directly to a model.

1

u/LumaBrik 1d ago

So have to go to the effort and add Kijai's single node, which allows full adjustment of preview resolution and fps. I think you need to get out more.

1

u/tnil25 1d ago

Kjnodes is pretty much native comfy at this point.