Video Trimmer

About this tool

Cutting the useful thirty seconds out of a long recording - for a chat post, a lesson slide or an application upload - is an even more common need than format conversion. This tool asks for just two time points: start and end. Plain seconds (12.5) and mm:ss (1:05) are both accepted, and leaving a side blank means the beginning or the end of the video.

There are two ways to cut. Lossless slicing (stream copy) re-encodes nothing: it copies the chosen stretch of the original streams, finishes in seconds and keeps bit-identical quality - the only catch is that the cut snaps to the nearest keyframe, so the start may be a fraction of a second earlier than requested. Frame-accurate trimming re-encodes the segment so the cut lands exactly on your time point. The tool picks the right mode automatically, and you can override it.

As everywhere on this site, the cutting is done by FFmpeg compiled to WebAssembly inside your browser: the video is never uploaded or stored, which matters for home movies and screen recordings.

Features

• Start/end trimming with plain seconds or mm:ss input, blanks allowed
• Automatic lossless keyframe slicing when the codec allows it: seconds, zero quality loss
• Optional frame-accurate re-encode at high-quality H.264 settings
• Reads MP4, AVI, MKV, MOV and WebM; outputs universally playable MP4
• Fully local processing with live progress and a cancel button

How to use

1. Drop the video into the box and use the preview to locate your segment
2. Enter start and end times (e.g. 1:05 to 1:30)
3. Keep the automatic trim mode (or force one) and click Cut clip
4. Preview the trimmed clip and download the MP4

Frequently asked questions

Lossless cut or frame-accurate trim - which should I pick?

Leave it on Automatic: the tool inspects the codec and uses lossless stream copying whenever possible - seconds to finish, zero quality loss - accepting that the cut may snap a fraction of a second early to the nearest keyframe. Switch to frame-accurate when the exact frame matters (beat-synced clips, for instance); it re-encodes and takes longer.

What time formats are accepted? Can I fill only one side?

Plain seconds with optional decimals (45, 12.5) or clock format mm:ss / hh:mm:ss (1:05, 1:02:03). Blank start means 0, blank end means the end of the video - filling only one side is fine.

Why is my video forced into re-encode mode?

Lossless slicing requires the video codec to be legal inside an MP4 container (H.264, MPEG-4 and the like). VP9 WebM files, for example, cannot be stream-copied into MP4, so the tool automatically switches to frame-accurate re-encoding at CRF 18 - visually almost indistinguishable from the source.

Is there any quality loss, and does the video get uploaded?

Lossless cuts are bit-identical; frame-accurate cuts re-encode at high quality where differences are hard to see. And no, nothing is uploaded: there is no backend able to receive your video - all work happens in your browser memory.

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