The problem it solves
Late-round BTD6 lags because the game can't simulate thousands of bloons and projectiles fast enough (why that happens). When you record a laggy session, your recorder fills every stall with a copy of the last frame to keep its constant frame rate (how that works). The file ends up mostly padding. Speeding it up in an editor just makes the padding go by faster.
Add pause-menu visits on top, and a 30-second late-game clip can contain only a few seconds of actual gameplay, buried in frames you'd have to cut by hand.
What LagCut does
- Scan. Each recorded frame is classified as gameplay, pause menu, or a near-identical repeat of the previous frame. This runs locally with the bundled Mediabunny library handling decode and encode.
- Review. The detected cuts (menu visits and repeat runs) are listed on a timeline. Remove any you want to keep, or add manual cuts by time range.
- Shape. Choose the output pace. Normal (1×) keeps real-time spacing between the remaining frames. Fast-forward (3×) triples it. One pace for the whole clip, no ramps.
- Export. A video-only MP4 is written at a constant frame rate. In Chrome and Edge, long exports stream straight to disk. Add your audio in an editor afterwards.
Measured on real creator footage
Three 30-second windows from three channels, covering 30 fps, 60 fps and sparse source footage:
| Source | Repeated frames removed | Menus cut | Result |
|---|---|---|---|
| lBankedl Mr P, round 268 | 638 of 901 | 0 | 8.8 s |
| Dave, round 400+ | 159 of 208 | 0 | 1.6 s |
| More Mehalic, boss tournament | 1,340 of 1,800 | 3 | 3.25 s |
The exported MP4s were checked for remaining repeated frames. For the round-268 sample, the same frame selection was also rendered independently and checked. The before/after clips are embedded on the tool page, with links to the original videos.
LagCut removes holds and menus that were recorded. It cannot reconstruct game states that the laggy game never drew. If the original jumps, the output jumps there too. Exports contain no audio, by design, so you can lay your original track or music back in.
Games
Each supported game has its own page and its own frame model, because what counts as "the game moved" differs per game. We ship a game only after testing it on real creator footage.
| Game | What's game-specific | Status |
|---|---|---|
| Bloons TD 6 | Pause-menu detection; reads the speed button to keep 1×/3× pacing | Live |
| They Are Billions | Compares only the map viewport, block by block, so HUD tooltips, the clock and webcams don't count; flags multi-second stalls | Live · guide |
| Vampire Survivors | — | Tested, not shipped: normal late runs record smoothly; lag only appears in extreme builds |
| BTD Battles 2 | — | Tested, not shipped: creator footage was smooth in every sample |
| RimWorld, Oxygen Not Included | — | Frozen frames were paused planning, not lag; a different tool |
Privacy and cost
Free, no account, no upload. The video is decoded, scanned and re-encoded entirely in your browser. Your machine does the work, which is why the prototype caps processing at the first 30 seconds of a clip: trim to the moment you want before dropping it in.
Status
LagCut is an early prototype and says so on the page. If something breaks on your footage, the FAQ covers the common cases (formats, browsers, long files).