Trim Video

Cut a video down to the stretch you actually need, without the file leaving this tab.

Runs on your deviceVideoWorkingNo account needed

What this tool does

Trim Video plays your file through an off-screen video element, captures the frames with captureStream, and writes the result with the browser's own MediaRecorder. That makes it a re-encode rather than a cut: nothing copies the original stream between two points, the tool watches the section you asked for and builds a new file as it goes.

The start and end points are typed as timecodes — bare seconds such as 12.5, mm:ss such as 1:23, or hh:mm:ss such as 0:01:23. Leaving End at blank runs to the end of the video, and the start sits at 0 until you change it, so cutting only the tail off takes one field. Anything the parser does not recognise is refused with the offending text quoted back, rather than quietly becoming zero and giving you the wrong clip.

Because the file is recorded while it plays, the job takes about as long as the section you keep: a two-minute clip needs roughly two minutes, and the progress bar follows playback instead of estimating. Keep the tab in front while it runs. Browsers throttle background tabs, and a starved capture ends with an empty recording — which the tool reports as an error instead of handing you a file that will not open.

Three constraints are worth knowing before you start. The output is always WebM, because the recorder is only ever asked here for WebM types — VP9 or VP8 video with Opus audio — so a destination that insists on MP4 means running the clip through Convert Video afterwards. A browser that supports none of those recording types is turned away at the start with a message naming Chrome, Edge and Firefox, rather than being handed some other container. And the input has to be something this browser can genuinely decode — MP4 with H.264 and WebM are the safe cases, an MKV opens only when it holds VP8, VP9 or AV1, a MOV needs H.264 or HEVC rather than ProRes, and AVI, WMV, FLV, MPG and MPEG-TS have no decoder here at all.

How to use it

  1. Choose the video. One file per job. It has to be a container this browser can play, so an AVI or a WMV is refused as it opens, with the reason named.
  2. Type the start and end points. Seconds, mm:ss or hh:mm:ss. Leave End at blank to run to the end of the video, and leave Start at 0 when you only want to drop the tail.
  3. Decide whether to keep the audio. Keep the audio is on by default and routes the track through a silent Web Audio graph. Switch it off when you want the picture alone.
  4. Set Quality and let it run. The Quality control is a bitrate in disguise: High is 8 Mbps, Medium 4, Small file 1.5, and the fourth option leaves the rate to the browser. Encoding runs in real time, so leave this tab in front until the progress bar reaches the end.

Processing & privacy

Runs on your device. Your file is processed directly in this browser.

Common use cases

Cutting the fumble off a screen recording

Most recordings open with a cursor hunting for the right window and close with a hand reaching back for the stop button. Trimming both ends takes half a minute.

Pulling one answer out of a long call

A recorded meeting is an hour of context wrapped around the ninety seconds a colleague needs. Cut video down to that stretch and send the clip rather than a timestamp.

Squeezing a clip past a size cap

A chat app or a web form that caps attachments will often take a shorter section written at 1.5 Mbps when it refuses the full recording.

Handling footage you would rather not pass around

Unreleased or confidential material can be shortened on your own machine, with no copy of it sent anywhere to be cut.

Questions

Does the footage go to a server to be cut?
No. Decoding, frame capture and recording all happen inside this browser tab, so nothing is transmitted and trimming still works with the network disconnected. The finished clip is written straight to a download.
Can it hand me an MP4 instead?
No. The recording is done by MediaRecorder, and this tool only ever asks it for WebM — VP9 or VP8 video with Opus audio — so there is no MP4 path here at all. If you need one, trim first and then run the WebM through Convert Video, which encodes on the OmniKitly processing service.
Why does it take as long as the clip itself?
The video is played back and recorded as it plays, so a five-minute section costs about five minutes of real time. There is no way to skip ahead without a proper encoder, which is why the setting note says to keep the tab in front.
Does trimming lose quality?
Yes. This is a re-encode, not a lossless copy of the original stream between two keyframes, so the picture is compressed again at whichever bitrate you chose. The frame size is kept exactly as it was, but a high-bitrate source cut at 1.5 Mbps will look softer than the original.
Are the cut points frame-accurate?
Close, but not exact. The start is a seek, so recording begins at the nearest frame the decoder can land on, and the stop is driven by a timer that checks playback about eight times a second. The summary hedges to match: it says the clip kept “about” a range, and the figures it prints are the points you typed clamped to the length of the video, not a measurement taken from the file that came out.
The clip came out silent — why?
Some browsers refuse to route a media element's audio into a recording. When that happens the tool says so in the summary instead of pretending the sound is there. Trying a different browser, usually Chrome or Firefox, is the practical fix.
My file will not open at all.
The browser has to be able to decode it. AVI, WMV, FLV, MPG and MPEG-TS are not playable here, an MKV works only when it holds VP8, VP9 or AV1, and a ProRes MOV will not load. Convert those to MP4 or WebM with Convert Video first, then trim the result.

Related tools