Trim Video

Trim a video in your browser. Open an MP4, MOV or WebM file, set a start and an end, play the selection, then download that section with its sound. Your device re-encodes the frames, so the cut lands on your times rather than the nearest key frame. Nothing is uploaded.

One clip, one span of it

Drop a video here

MP4, MOV or WebM, up to 10 minutes and 2 GB. Your video stays on your device.

File: —
Source: —
Duration: —
Start: —
End: —
Result: —

Verified facts

Inputs: MP4, MOV, WEBM
Output formats: MP4, WEBM
Processing: In your browser. No media upload.
Access: Free · No signup

MP4, MOV and WebM are containers. Whether a file decodes depends on the codec inside it and on this browser or device. Not every file in these containers will open.

How to use it

Press Open video to choose a local file, or Try a sample. The tool reads MP4, MOV, WEBM. Whether a file decodes depends on the codec inside it and on this browser.
Set the start and the end. Drag the two handles on the Trim range track, or type into the Start and End fields. Start here and End here take the time from the playhead. Whole clip puts the selection back over the whole source.
Press Play selection. It previews the selected section and stops at its end.
Read Result, Size, Format and Sound. Then press Download video. You can stop the export while it runs.

Limitations

One section of one clip. There is no splitting into several files, no joining of clips, no reordering and no effects.
Start and end sit on millisecond steps. Either end snaps to the exact clip end when it lands within half a step of it, so a full selection is the whole file rather than a rounded millisecond of it. The shortest selection is 0.1 seconds, or the whole clip when the clip is shorter than that.
The end is exclusive: a frame that begins at the end time belongs to what follows. The start cuts across the picture rather than filtering frame times. A start between two frames keeps the frame you see at that moment and writes the rest of it. The export writes no picture from outside the selection.
Times are elapsed seconds of picture, counted from the first frame. A source whose timestamps start above zero still opens at zero here, and its export begins at zero. A selection is a stretch of video, so sound that runs on past the last frame cannot be reached.
The export decodes and re-encodes every frame in the selection, so this is not a lossless copy and the cut is not restricted to key frames. Frame timing inside the selection is carried through, including variable frame rates, and the frame rate does not change.
The picture keeps the source display size, after the rotation and the pixel aspect ratio the file declares. A source with an odd display width or height is written one pixel shorter on that edge, because video encoders take even numbers. The whole picture is scaled into that size rather than cut, so its shape shifts by a fraction.
The export reduces a source longer than 1920 pixels on its longest edge to fit, and names the reduced size before it runs. The picture is never enlarged.
A file with sound is written as VP9 or VP8 in WebM with Opus audio. A file without sound is written as H.264 in MP4 where the browser can encode it, and as WebM otherwise. The format is resolved when the video opens and named before the export runs. It holds for every section of that file.
WebM is the format for sound because this tool re-encodes the sound alongside the selected frames. The AAC encoder browsers expose put the sound tens of milliseconds behind the picture in testing, while Opus held them together. WebM plays in browsers and in most current editors. Some older players and cameras read only MP4.
The primary video track and the primary audio track are kept. Further audio tracks, subtitle tracks and chapters are not written. A source whose audio cannot be decoded and re-encoded fails with a message instead of exporting silent video.
Sound keeps its position against the picture. A source whose audio starts after its first frame keeps that delay, and a selection that reaches past the end of the sound is silent from there on. A selection that lies outside the sound of the file is written without an audio track, and the tool names that before the export runs.
The audio track can end up to 60 milliseconds before or after the end of the selection.
Colour is not managed. The browser re-encodes an HDR or wide-gamut source without a conversion this tool controls, and its colour can shift.
Sources are read up to 2 GB, 10 minutes, 16 megapixels per frame and 16,384 pixels on the longest edge, measured on the display size and on the coded raster. A file that exceeds one of these limits fails to open, and the error names the limit.
The export stops above 512 MiB of written video, because the file stays in memory until the download starts. This bounds the file. Decoding and encoding hold memory beyond it.
An export can be stopped while it runs. Nothing is uploaded and nothing is saved between visits.
MP4, MOV and WebM are containers. Whether a file decodes depends on the codec inside it and on this browser or device. Not every file in these containers will open.

Setting the start and the end

The fields take hours, minutes, seconds and milliseconds. They take plain seconds as well, so 4.5 is four and a half seconds. A value outside the clip snaps back and writes a message instead of moving the handle. So does a value that would leave a selection shorter than the minimum.

Neither edge can pass the other. Each one stops 0.1 seconds short of its partner. That is the shortest selection the export takes. A clip shorter than 0.1 seconds selects whole instead.

Focus a handle and the arrow keys move it 0.1 seconds a step. Shift and an arrow move it one second. Page Up and Page Down move it five seconds. Home and End send it to its own limit.

Selections on a source of 6.000 seconds.
Start and End	Result	What is kept
0 to 6	6.000	The whole clip. The Whole clip button sets it.
2 to 3	1.000	Everything from 2 seconds up to 3, and nothing at 3.
0.5 to 1.25	0.750	The fields read milliseconds, so 1.25 is one and a quarter seconds.

What the Sound line tells you

The Output panel says what your selection will do to the sound before you press Download video. Sound reads one of four things: Source audio kept, Silent in this selection, Partly silent in this selection, or No audio track in the source.

The two silent readings describe the source rather than the export. A file can carry sound over one stretch of a longer clip. A selection outside that stretch has nothing to write.

Privacy and processing

Reading, playback and encoding happen locally in this browser. The tool does not upload your video to Avo servers. You need no account.

The browser fetches this page and the optional sample clip over the network like any website. Local media processing is not an offline mode. It is not a statement about site analytics.

The tool keeps nothing between visits. Replacing the source releases the previous file and its preview. A downloaded export stays wherever you saved it.

Questions

Where exactly does the cut land?

On the times you set. Key frames do not move it. The end is the first moment left out. A start between two frames keeps the frame you can see at that moment. The source frame timing decides how close a given time sits to a frame. This tool claims no general frame exactness.

Is this a lossless cut?

No. This tool decodes the frames inside the selection and encodes them again. That is a second generation of compression. A cut that copies the source bytes can only start where a key frame already sits. This one starts where you asked.

Why is my export a WebM and not an MP4?

Because the source has sound. This tool re-encodes the sound alongside the selected frames. The AAC encoder browsers expose put the sound tens of milliseconds behind the picture in testing, while Opus in WebM held them together. A source without an audio track comes out as H.264 in MP4 where the browser can encode it, and as WebM where it cannot. The Output panel names the format before the export runs.

Can I split a clip into several files, or join two clips?

No. One export writes one section of one source. Run the tool again with a different start and end for the next section. Joining clips is not part of this tool.

Is the audio kept?

The export keeps the primary audio track and re-encodes it. It holds its position against the picture. The Output panel says what your selection will do to it before the export runs: Source audio kept, Silent in this selection, Partly silent in this selection, or No audio track in the source.

My video starts at a timestamp above zero. Which times do I type?

Type elapsed seconds counted from the first frame. A file whose timestamps begin at two seconds still has its opening frame at 0. The playhead, the fields and the exported file all use that same count.

Why will my MOV or MP4 not open?