How to trim a video (cut the start and end) without re-encoding
You've got a clip with ten dead seconds at the start and some fumbling at the end. You don't need a video editor — you need to trim. Here's how trimming works and why the method matters for quality and speed.
Trimming vs. editing
Trimming just cuts a clip down to a start and end point — keeping the middle, dropping the rest. It's not the same as editing (adding transitions, text, multiple clips). Because you're only choosing where the clip begins and ends, trimming can be fast and lossless if done right.
The key idea: stream copy vs. re-encoding
- Re-encoding rebuilds the video frame by frame. It's slow and throws away a little quality every time — unnecessary if you're just cutting.
- Stream copy keeps the original video data untouched and only changes where it starts and stops. It's near-instant and lossless — the output looks identical to the source.
For a simple trim, stream copy is what you want. The one caveat: cuts land on the nearest keyframe, so the exact start point can shift by a fraction of a second. For most clips that's invisible; for frame-perfect cuts you'd need re-encoding.
How to trim cleanly
- Load the video and find your in-point (where it should start) and out-point (where it should end).
- Set start and end times.
- Export — with stream copy, it finishes almost immediately.
Privacy and file size
A browser-based trimmer processes the video on your own device, so a personal clip never gets uploaded to a server. And trimming naturally shrinks the file — a shorter clip is a smaller file. If you only need the audio from the clip, you can instead extract it to MP3.