Topaz Upscale Video (fal)

Topaz is the paid default everyone benchmarks video upscaling against - when someone builds an open video upscaler, "I cancelled my Topaz subscription" is the trophy they post. This node gives you Topaz's video upscaler through fal.ai on a pay-per-clip basis, which is a genuinely different deal from the subscription: no monthly fee, you pay for the clips you actually run.

It's a cloud call - the video goes to fal, Topaz's model does the work, you get a URL back. Nothing runs locally.

How it works

Video upscaling is its own hard problem, separate from image upscaling, because every frame has to agree with its neighbours. Run a per-frame image upscaler on video and fine repeating textures shimmer - the model resolves them differently each frame and the result is unwatchable. Topaz is built for the temporal job: it upscales with frame-to-frame consistency in mind, which is why it's been the commercial standard for so long. You feed it a clip and a factor; it hands back a larger, cleaner one.

The inputs and outputs that matter

• upscale_factor (required, default 2, range 1–5 in 0.1 steps) - how much bigger. The fine step size lets you hit a specific target resolution rather than only doubling.
• the source video - supply it as a video (VIDEO) socket or an input_video_url string already on fal. One or the other.
• use_fps + target_fps (optional) - turn use_fps on and set target_fps (up to 60) to also change the frame rate, i.e. do frame interpolation alongside the upscale. Leave use_fps off to keep the original timing.

Output is a video_url STRING - a link to the finished clip on fal, not a previewable VIDEO. Route it through the pack's Fal Save Media from URL node to download it, or into a downstream fal node's *_direct_url. Those URLs expire; save what you want.

How to install it

Ships in gokayfem's ComfyUI-fal-API pack. ComfyUI Manager: search ComfyUI-fal-API, install, restart. Manual:

cd ComfyUI/custom_nodes
git clone https://github.com/gokayfem/ComfyUI-fal-API.git
pip install -r ComfyUI-fal-API/requirements.txt

Add your fal key (copy config.ini.example → config.ini, paste from fal.ai/dashboard/keys, or export FAL_KEY=your_key), restart. No download.

Common issues & troubleshooting

The cost adds up fast on long footage. Video upscaling is priced per clip and per second under the hood - cheap for a five-second test, ruinous for two minutes at high factor. Upscale short segments, or downscale your factor, before committing a long render.

No video and no input_video_url. You need to give it a source one way or the other. If your clip is local, feed the VIDEO socket; if it's already on fal (say, from an UploadVideo_fal node), use the URL field.

Frame rate changed unexpectedly. That's use_fps. If it's on and target_fps is set, Topaz retimes the clip. Turn use_fps off to preserve the original frame rate.

Output won't preview. It's a URL string - download it via Fal Save Media from URL first.

Insufficient funds / credit lag. fal bills per call and is legit; top-ups have occasionally posted late. Let credits settle rather than repaying. fal's error text surfaces in ComfyUI.