Compare Video

Judging video by alt-tabbing between two players is a bad way to work. Frame numbers drift, your eyes adapt, and after three swaps you genuinely can't tell which clip had the better motion. Compare Video fixes that the obvious way: two VIDEO inputs, both playing on the node itself, a divider you drag left and right, one clock driving both sides so the same moment of each clip is on screen at the same time.

It's a viewer, not a pass-through. There's no output socket - it's an output node, so it runs when you queue the graph and draws its panel on the canvas. If you were looking for something to sit mid-graph, this isn't it; wire it in as a leaf and leave it.

What you wire in

Both inputs are optional: video_a on the left of the divider, video_b on the right. Leave one empty and you just get the other. Anything that produces the VIDEO type works - a loader, or the decode end of a video model's pipeline.

The use cases that actually matter are the boring investigative ones: same seed and prompt across two schedulers, a LoRA at 0.8 versus 1.0, one checkpoint against its distilled sibling, or a straight before/after for an upscale or interpolation pass. Motion is where video comparisons go wrong by eye - a clip can look sharper frame by frame and still have worse motion between them - and a divider at a fixed instant is the only cheap way to see both at once.

Keep the pair comparable: same resolution, same frame rate, same length, same frame count. The node plays both from one clock, so mismatched clips will show you frame n against frame n, and if one is 24 fps and the other 30, that alignment drifts as the clip plays. That's fine for a vibe check and misleading for anything else.

What's happening underneath

Each side gets written to the temp folder - under the prefixes was.compare.video.a and was.compare.video.b - and the node serves them to its own in-canvas player. Because the panel is drawn by the pack's frontend code rather than by ComfyUI itself, you're relying on the pack's web assets loading: if the node shows up empty, check the browser console and hard-refresh before you file anything, that clears it most of the time.

Also worth knowing: those temp files are real files, and they accumulate. Every comparison run writes two clips to temp. If you're iterating twenty times on a 10-second 2K generation, you've just quietly parked a lot of gigabytes on the drive your ComfyUI temp lives on. Clear temp between sessions.

Install

Compare Video is part of WAS Node Suite v3. ComfyUI Manager, search WAS Node Suite v3, install, restart. Manually:

cd ComfyUI/custom_nodes
git clone https://github.com/WASasquatch/was-node-suite-comfyui.git

Requires ComfyUI 0.14.0+ and Python 3.10+ - the pack is written against ComfyUI's newer backend node API, so a stale ComfyUI is the usual reason a node like this won't appear at all. Nothing gets pip-installed and nothing gets downloaded; first start writes config.yaml and its folders under <ComfyUI user dir>/was-node-suite/ and takes a second longer than later starts.

Worth flagging for anyone arriving from an older tutorial: search results for this pack are dominated by its 2023–2024 life, when it was a 220-node collection that pinned OpenCV and InsightFace and broke whenever ComfyUI updated. The author was candid at the time about not being able to keep up with it. The current pack is a 463-node rewrite with zero default dependencies - so if a guide is telling you to install packages to make WAS nodes load, it's describing the old one, and it's describing a problem this version doesn't have.

The honest limits

It's a UI node: no output to route, no automation, nothing to script. It plays what you give it and that's all. And if you're comparing two clips you already exported, a player-side A/B like this is often slower than just opening both files - the payoff is when the clips come straight off the graph and you're comparing settings, not deliverables.