Video Comparer MXD

When you're iterating on a video - new LoRA, different sampler, higher CFG - you need the old clip and the new clip in the same place to tell whether you actually improved anything. Video Comparer MXD gives you the in-node A/B compare that the image side of ComfyUI has had for years (rgthree popularized it for stills), now applied to videos. New clip first, original beside it, slider between them.

What it does

• new_video (required) - the clip you just generated.
• original_video (optional) - the reference clip. Leave it unconnected and the node just previews the new one, which is a legitimately useful fallback.

The output is new_video, passed straight through - the pack description is explicit: "new video displays first and is passed through." So it's both a comparator and a passthrough node. You can drop it at the end of your graph after the video-combine, and the video still flows onward to a save/preview node if you want it saved too.

Mechanically it's simple and transparent: each video is rendered to an mp4 in ComfyUI/output/previews with a timestamped filename, and the frontend shows them side by side with a slide handle. That preview-directory habit is worth knowing about - those mxd_video_compare_*.mp4 files accumulate, so clear output/previews occasionally if you run a lot of compares.

Why you'd reach for it

Video iteration is expensive - a WAN 2.2 run is minutes, not seconds - and the whole point of A/B is not having to trust your memory of clip #3 from forty minutes ago. Having the original frame-for-frame against the new one is the difference between "this LoRA looks better" and "wait, it actually changed the motion." It's one of the pack's most genuinely useful daily-driver nodes precisely because it's boring infrastructure done right.

Gotchas

• It's built on ComfyUI's newer comfy_api VIDEO type. Not showing up in your menu? Update ComfyUI, restart, and it'll register.
• It doesn't save the original to your main outputs folder - originals only go to the previews dir for comparison. If you want the original archived, save it elsewhere before wiring in this node.
• No frame-rate or resolution matching here: whatever each video is, that's what you compare. Compare like-with-like and the slider makes sense.

Install

ComfyUI Manager → search Maxed Out → install → restart, or:

cd ComfyUI/custom_nodes
git clone https://github.com/Maxed-Out-99/ComfyUI-MaxedOut

No requirements.txt, no model downloads. Under MXD/video in the menu.