Trim Video Without Re-encoding
Trim video – cut the beginning, cut the end, done: the tool copies the chosen part of your video unchanged into a new file – no re-encoding, so it takes seconds and loses no quality. Everything happens in your browser.
Source: MDN – VideoEncoder.configure(): bitrate in Bit pro Sekunde. Updated: .
How it is calculated
Shorten a video without re-encoding it
Most online video cutters upload your video, re-encode it and send it back – which costs time and picture quality. This tool works differently: it takes the already-compressed picture and sound data of the chosen section bit for bit into a new file. That is why even a long video takes only seconds, and the quality stays exactly the same.
How it works
- Drop or choose a video (MP4, MOV from an iPhone, WebM, MKV).
- Set start and end: type a time (1:30 or 1:30.5), or play the video to the spot and tap “Use current position as start” or “… as end”.
- Click “Trim video”, check the result and download it.
Why the start is sometimes a little earlier
Videos do not store every frame in full. Only keyframes are complete pictures; all other frames only contain the changes from the previous one. Without re-encoding, a video can therefore only start at a keyframe. If your start lies between two keyframes, the cut begins at the keyframe before it – the result shows the actual start time. In phone videos keyframes are usually just one or two seconds apart. The end, on the other hand, can be set freely.
What stays and what doesn't
- Picture and sound stay unchanged, as do the resolution and the rotation of portrait videos.
- Format: MP4 and MOV are saved as MP4, WebM as WebM, MKV as MKV.
- Size: the file shrinks roughly by the share you cut away. To fit a fixed size, use Compress video afterwards.
- Limits: joining several sections, subtitles and chapters are not supported. The result is built in memory; very large sections (several GB) may fail on weaker devices.
Privacy
The video is only read piece by piece from your device; there is no upload and no server that sees it. Reading and writing the video files is handled by the open-source library Mediabunny (MPL-2.0), which only loads when you pick your first video.
Only need to shorten audio? Use the MP3 cutter. Turn a clip into an animation with Video to GIF.
Frequently asked questions
Is my video uploaded?
No. The video is read and trimmed in your browser. It never leaves your device.
Does trimming reduce the quality?
No. The section is copied without re-encoding, so picture and sound stay bit for bit the same.
Why does my cut start slightly earlier than I chose?
Without re-encoding a video can only start at a keyframe. If your start lies in between, it moves back to the previous keyframe – usually less than two seconds. The actual start time is shown with the result.
How do I trim a video on iPhone?
Open this page in Safari, choose the video from your library, set start and end and trim. The result is saved as MP4.
Is this an alternative to trimming with VLC?
Yes, for simple cuts. Like a stream copy in desktop tools, it keeps the original quality – but runs in the browser without installing anything.
How long can the video be?
The file can be up to 4 GB. It is read piece by piece; only the trimmed section ends up in memory.
Sources and legal basis
- MDN – VideoEncoder.configure(): bitrate in Bit pro Sekunde
- MDN – EncodedVideoChunk.type (key/delta)
- ITU-T H.264 – Advanced video coding for generic audiovisual services
- Mediabunny 1.61.0 – Vanilagy (MPL-2.0), Quelltext
- Lizenzen der Medien-Werkzeuge (MPL-2.0)
As of:
Related tools
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