Video Trimmer (Buff)

Every video workflow hits the same wall eventually: you generate a clip, and half of it is junk. Warm-up frames where the motion hasn't settled, two seconds of dead air at the start, a tail that drifts into mush. The usual fix is to leave ComfyUI and open an editor, which is a pain mid-graph. Video Trimmer - the one node in the tiny ComfyUI_VideoCutter pack - plugs that hole directly in the graph: Load Video -> Video Trimmer -> Save Video. It takes a native ComfyUI VIDEO object, cuts it by time or by frame number, and hands you back another VIDEO that your existing save/encode node will happily eat.

This matters more than it sounds, because ComfyUI is the only local tool where chaining video models, conditioning, and post-processing in one graph is even practical. If you've ever had to drop a clip to an external cutter, cut it, and re-import just to shave off filler frames, you know the friction. This node removes that round-trip.

How it actually works

The key detail is that it trims in memory, not by re-encoding. It grabs the decoded components of the incoming VIDEO (frames tensor, audio, metadata, frame rate), converts your time or frame inputs into a frame slice, cuts the tensor, and rebuilds a fresh VIDEO object. Audio is sliced to match - it converts the frame range to audio samples using the frame rate and sample rate so the soundtrack stays in sync. No file-system round-trips, no ffmpeg dependency, no model downloads. It's about as lightweight as a node gets.

That simplicity has one real requirement, though: the node imports comfy_api.latest from ComfyUI core to access the native VIDEO API. If your ComfyUI is old enough to lack that, the node fails at load with a clear import error. Keep ComfyUI updated and you're fine.

The inputs that matter

You'll set two things in practice: trim_mode (a toggle, time or frames) and the matching start/end pair.

• trim_mode - "time" is the default and the friendly one. Switch to frames when you want surgical precision.
• start_time / end_time - seconds as floats. Set end_time to 0 to cut from start_time to the very end.
• start_frame / end_frame - integers, same deal: end_frame = 0 means "everything to the end."

One trap: the end values are exclusive, which matches Python slicing. end_frame = 192 with start_frame = 48 keeps frames 48 through 191, not 192. Don't be the person who wonders why their last frame vanished.

Outputs

The star is trimmed_video (VIDEO), which wires straight into your Save Video node. The rest are metadata you mostly don't need but are nice for validation: duration_seconds, frame_count, and the resolved_start_frame / resolved_end_frame - the actual frames used after clamping. If you're chaining automated workflows, those resolved values are how you confirm the cut landed where you thought.

Installing it

Via ComfyUI Manager, search for ComfyUI_VideoCutter and install. Or do it by hand:

cd ComfyUI/custom_nodes
git clone https://github.com/benjamin-bertram/ComfyUI_VideoCutter

Then restart ComfyUI and look for Video Trimmer under the Video Editing category. There are no dependencies, no requirements.txt, no models to fetch. One stale README detail: it tells you to put the folder in as ComfyUI_VideoCutter_CodexAPP, which is an artifact of the author's dev machine - the clone lands as ComfyUI_VideoCutter and works fine.

Troubleshooting

• Node shows up red / won't import: your ComfyUI predates the native VIDEO API. Update ComfyUI core.
• Errors about empty videos, missing frame rate, or malformed tensors: the input isn't a proper decoded VIDEO. It has to come from a node that outputs the native type - typically Load Video.
• "Invalid trim range": your start is past your end, or off the end of the clip. Fix the numbers.
• No audio after trimming: only happens if the source VIDEO had no audio track to begin with; the node preserves it when present, not when absent.

It's a small, niche node from a one-custom-node pack - don't expect a big community around it. But for the specific job of cutting generated footage down to the good part without breaking your graph, it's exactly the tool you reach for. The name isn't a lie: it trims video. That's all it does, and that's enough.