LagCut questions, answered.
Formats, limits, privacy, browsers, and what the tool can and can't do. If your question isn't here, the how-it-works page goes deeper.
Is LagCut free?
Yes. LagCut is a free browser-based prototype. There's no account, no upload and no watermark.
Does LagCut upload my video anywhere?
No. Scanning, review and export all run inside your browser. The file never leaves your device. That's also why large videos take a while: your own machine is doing the work.
What does LagCut actually remove?
Two things. Pause-menu visits (the frames where the BTD6 pause menu is on screen) and repeated frames, where the recorder wrote the same image again because the game hadn't produced a new one. Everything else stays.
What does it not do?
It can't recreate gameplay that was never recorded. If the game stalled and then jumped, the output will show that jump, because those frames don't exist. It also doesn't edit audio: exports are video-only so you can add your original audio or music in an editor.
What formats does it accept and export?
Common browser-playable formats such as MP4 (H.264) and WebM work as input. The export is a video-only MP4 at a constant frame rate. If a file won't open, re-encoding it to MP4/H.264 first usually fixes it.
Which browser should I use?
Chrome or Edge. They can save long exports directly to disk. Other browsers work but may buffer the whole export in memory, which can fail on long clips.
Is there a file size or duration limit?
The prototype scans and exports the first 30 seconds of whatever you drop in. Longer files load fine, but only the first 30 seconds are processed, so trim to the section you want first (any editor, or a free tool like LosslessCut). This keeps scans fast and stops long files from tying up your browser.
What's the difference between Normal and Fast-forward speed?
Both use only the real (non-repeated) frames. Normal (1×) plays them at the original game pace. Fast-forward (3×) plays them at three times that. The whole export uses one pace, so there are no speed ramps to fix later.
Does it work for games other than BTD6?
There's a dedicated version for They Are Billions at lagcut.h4tools.com/they-are-billions/, with its own frame model (it watches only the map viewport and ignores the HUD and webcams). Each game gets its own version only after we've verified it on real creator footage. We tested Vampire Survivors and BTD Battles 2 and didn't ship them: normal late runs in both were recorded smoothly, so there was nothing to fix. The BTD6 page will still remove repeated frames from any recording, but its pause-menu detection is BTD6-specific.
Why does my clip look jerky after speeding it up in my editor?
Because the repeated frames from lag are still in the clip. Speeding it up makes them go by faster but doesn't remove them. Removing them first, then setting the pace, is what makes fast-forward footage look smooth. See the guide on speeding up BTD6 footage.
Can I adjust the cuts it finds?
Yes. After scanning you get a cut list on a timeline. You can remove any cut you want to keep and add manual cuts by time range before exporting.
Is this a finished product?
No. It's an early prototype, labelled as such on the tool. It's been validated on footage from several BTD6 channels covering 30 fps, 60 fps and sparse recordings, but expect rough edges.