Questions about editing video in your browser

No. Your video is read from your disk into the browser tab and processed there by FFmpeg WebAssembly. The application has no upload endpoint, so there is nothing to upload to. The only file that comes down over the network is the FFmpeg engine itself, and that is code, not your data.

No. There is no server-side storage of any kind. Your file exists in the tab's memory while you are working, and it is gone when you close the tab.

Yes, on the pages — not on your files. Every page loads P-analytics from api.panalytics.money, which records a cookie-less page view: the page address, the referrer, any campaign parameters in the URL and how long the page stayed open. Your browser and a country come from the request itself, as with any web request. It has no visibility into the editor or into anything about the video you load. The privacy page describes this in full.

After the first successful edit, largely yes. Once the page and the ~32 MB WebAssembly engine are in your browser cache, the editor keeps working offline. The analytics request simply fails, which changes nothing.

Two ways. Right-click anywhere on the timeline bar for a context menu and pick Cut, Speed up or Slow down — the edit lands at that exact time. Or scrub the playhead to where you want the edit to start and press "+ Add edit" below the cards.

Click an edit card, or its coloured band on the timeline, to make it active. Two handles appear on the timeline that you can drag to resize the range, and the card has Start and End fields if you would rather type exact values.

Yes. Cuts, speed-ups and slow-downs can all coexist on the same timeline, and pressing "Apply All Edits" turns the whole set into one FFmpeg filter graph. The video is decoded and re-encoded once regardless of how many edits you stacked.

The editor flags them and blocks the apply button until you fix it. Overlapping ranges have no unambiguous meaning — a section cannot be both removed and slowed down — so they have to be separated first.

You can preview where it lands, not what it will look like. Clicking the timeline seeks the video player, so you can check the exact in and out points. The card also shows the estimated duration of the finished video, which updates as you add edits. Once the encode finishes, the result plays inline so you can check it before downloading.

No. Segments are always re-joined in their original order. This is a trimmer with three operations, not a non-linear editor.

Yes. Mark the range you want with any edit card and press "Keep only this part". The editor replaces that edit with cuts covering everything before and after the range, so only the marked section survives the encode. It is the same thing as adding the cuts by hand, done in one click.

Trim a video to one section

Yes. Load the file, then choose a different output format, a resolution cap or mute without adding any edits, and the apply button becomes "Convert video". It runs the same pipeline with a single passthrough segment, so a format or resolution change is still decoded and re-encoded rather than remuxed. Mute on its own is the exception: with the output kept at MP4, MKV or MOV, the editor tries a lossless stream copy first and only re-encodes if the source codec cannot go in that container.

All converters

Yes. Space plays and pauses. I and O set the active range's start and end to the playhead. Delete or Backspace removes the active edit, and Esc deselects it. The arrow keys seek one second, Shift plus an arrow seeks five, and the , and . keys step a single frame. Ctrl+Z (Cmd+Z on a Mac) undoes; Ctrl+Shift+Z or Ctrl+Y redoes.

Yes. A Cancel button is shown while FFmpeg is running. Cancelling stops the engine outright rather than asking it to finish, so it is reloaded from your browser cache on the next run — a short pause, not another 32 MB download.

It removes everything between your start and end time and joins the surrounding footage together, so the video gets shorter. It does not leave a gap, a freeze or a black frame. There is a fuller write-up on the cut-a-video page.

It plays the selected segment faster — 1.5x, 2x, 4x, 8x or a value you type — while everything outside the selection stays at normal speed. Audio is retimed with FFmpeg's atempo filter, which changes tempo without changing pitch, so sped-up speech does not sound squeaky.

The same in reverse: the selected segment is stretched to 0.75x, 0.5x, 0.25x or a custom factor, and the audio is stretched to match at unchanged pitch. No new frames are generated, so how smooth it looks depends on the frame rate of your source footage.

Speed-ups run from 1.1x up to 16x, and slow-downs from 0.99x down to 0.1x, either from the presets or typed into the card. Factors outside atempo's own 0.5-to-2.0 range still work because the editor chains several atempo filters together automatically.

There is no limit imposed by the site, because there is no server to impose one. The real constraint is your device's memory: the input file, FFmpeg's virtual filesystem and the output all sit in RAM together. A few hundred megabytes is comfortable on most machines; multi-gigabyte 4K footage is where a tab starts to struggle.

It works, but desktop is the better place for anything long. A phone has to download the same ~32 MB engine, hold the whole video in memory and run the encoder on a mobile CPU. Short clips are fine; a half-hour 4K recording will be slow at best and may exhaust the tab's memory.

You can open MP4, MOV, MKV, WebM and AVI. You can export MP4, MKV, MOV or WebM. MP4, MKV and MOV are written as H.264 video with AAC audio; WebM is written as VP8 with Opus, which the container requires and which encodes noticeably slower.

Slightly. Every operation runs through a filter graph, and a filtered stream cannot be stream-copied, so the output is re-encoded with libx264 at the ultrafast preset and CRF 28. On ordinary footage the difference is hard to spot; on very clean, very detailed source you may notice it.

Yes — use the max-resolution control. Capping the output at 1080p, 720p or 480p reduces the file substantially and makes the encode finish sooner. It only ever scales down, so a 480p source is never upscaled.

Downscale a video to 1080p, 720p or 480p

Yes. Tick the mute option and the output is written without an audio stream. It works on its own, with no other edits, or alongside cuts and speed changes in the same encode.

Remove audio from a video

The browser is downloading the ~32 MB FFmpeg WebAssembly core. That happens once; afterwards it is served from your browser cache and later edits start immediately, including on future visits.

No. If FFmpeg cannot find an audio stream, the edit is automatically retried without the audio branch of the filter graph and you get a valid silent video back.

No. The file you download is exactly what FFmpeg produced. Nothing is stamped on it, and there is no paid tier that removes anything.