Will trimming reduce quality?
Not when the file can be copied as-is. You will see a green note. If the file must be re-encoded, you will see an amber note — that path may change quality.
Trim video without quality loss
Cut a clip in your browser. When the container and codec allow it, the original media is copied as-is — no re-encode, no quality drop, usually done in a second. If this file cannot be copied, we tell you and re-encode instead.
Frequently asked questions
Why isn’t the cut exact to the frame?
Copying without re-encoding has to start on a keyframe. The range may expand or shrink slightly so the file stays valid. If you need frame-accurate cuts, use the regular trim page and accept a re-encode.
When does this fall back to re-encoding?
When the output container cannot hold the original codec, or a track cannot be copied. You get a warning; the slower path then runs instead of failing silently.
How is this different from the regular trim page?
https://cutfa.st/features/trim is the general “trim video online” page. This page is for people who specifically want no quality loss and an honest copy-or-re-encode message.
Do you upload my video?
No. Trimming runs locally in your browser.
Which files copy instantly?
Common MP4/MOV/MKV files with widely supported codecs usually copy. Changing to a container the codec cannot enter, or using ProRes-style files, often needs a re-encode.