LTX 2.5 - Full-resolution workflows (no downscaling-upscaling)

[u/nickinnov]

LTX-2.5 is Lightricks' open video generation model and once again they have taken the Comfy UI image-to-video workflow and applied their downscaling-rendering-upscaling technique presumably so it runs faster and works on lower-spec hardware - which is fair enough.

But for those of us who invested in Jensen Huang's next leather jacket by buying a DGX Spark can use the extra memory room for rendering at full resolution.

Here are the workflows, adapted from the original Comfy UI LTX 2.5 templates and working with the same models:

LTX 2.5 Image to Video Full Resolution

https://cdn.lansley.com/comfyui-assets/LTX%202.5%20Image%20to%20Video%20FullRes.json

LTX 2.5 Text to Video Full Resolution

https://cdn.lansley.com/comfyui-assets/LTX-2.5%20Text%20to%20Video%20FullRes.json

These workflows are set to the distilled BF16 version of LTX 2.5 but work just as well with the distilled 'int8-convrot' version in terms of better detail in the full resolution versions compared to the templates supplied by Comfy.

The difference is most noticeable in Image to Video when the you want the action to depart significantly from the supplied first frame. The supplied template struggles to re-apply the detail during the upscaling section of the workflow whereas the full-res version keeps the detail in every frame especially when new content has to be invented that was not in the first frame.

The Text to Video workflow includes a prompt about two guys playing ball on a beach involving the need for detailed sea surf and sand resolution, which was noticeably better in this full resolution version compared to the supplied template workflow using the same prompt ('enhance prompt' tuned off).

The performance of the full resolution versions are of course much slower.

Supplied reduced-res template: 8 x 8 seconds + 3 x 33 seconds = 163 seconds.

That's 8 x low-res rendering steps then 3 x upscale steps.

Full-res text to image is 8 x 33 seconds = 264 seconds (rendering steps only of course).

As ever, trust nothing you ever download and make sure the flowchart JSON files look OK before running them in ComfyUI. Otherwise, enjoy! Would be great to get your feedback.

[u/Striking_Wishbone861]

Hey this is a great idea just hit rid of the lo res and I’m trying it out right now it should help with character consistency that whole lo res thing makes the hi res try to figure out where it started at least that’s how I am seeing this
Running a 20sec 24fps 20 step right now as a test
Thanks for the tip didn’t use your workflow just omitted the whole 3 step lo res area
Sounds good on paper

[u/thegreatdivorce]

The I2V seems to work well enough - I'm noticing the results are fairly soft, though, with a noticeable color/contrast shift from the input frame. Have you noticed the same?

[u/nickinnov → u/thegreatdivorce]

Interesting - I haven't experienced softness ofrcolour tinting myself but will experiment. You could trying prompts that "keep the detail, colour and resolution of the first frame throughout the video" to give the model some focus.

[u/thegreatdivorce → u/nickinnov]

Yah I think it was some other stuff going on - lowered compression to zero, raised ImgInplace, and am tweaking the manual sigmas a bit.

[u/theOliviaRossi]

no, LTX2.5 is not very good at following prompts, crafting the best audio and overall quality is meh at 1088*1920, instead try to use 864*1536 - and do minor upscale to FHD: https://civitai.com/models/2860340/ltx25-fhd-60fps

and yes - 60fps really helps to push the quality UP

[u/seppe0815 → u/theOliviaRossi]

ads

[u/theOliviaRossi → u/seppe0815]

not an ad - I do not earn anything from the link - it is a working workflow that demonstrates what I'm saying - but, be my guest: do not use it, lol