Trim a video without re-encoding it
Cut the part you need in seconds. The original quality is kept. No upload.
Processed on your device. Your video is never uploaded. How we know
Drop a video to trim
Drop a video here, paste it with Ctrl+V, or choose one from your device.
ClipHeron runs in your browser. We don’t receive your videos, their names or anything in them. Ads on this page load separately and are not given your files. What happens to your video
How to cut a part out of a video without losing quality
Most online cutters upload your file and then re-encode the whole thing to make the cut, which takes minutes and softens the picture. ClipHeron copies the frames you keep straight into a new file. A two-minute cut from a 2 GB recording takes about as long as copying 400 MB on your disk, and the frames are byte for byte the ones the camera wrote.
The only catch is that a lossless cut has to start on a keyframe. The keyframes guide explains why; the short version is in the “why the cut snaps” section below, and the tool always tells you exactly where your cut will land.
- 1
Add your video
Drop or choose an MP4, MOV, WebM or MKV. The preview appears on a dark stage and the filmstrip fills in along the timeline.
- 2
Set the range
Drag the start and end handles, type timecodes, nudge by one frame or one second, or press I and O while the preview plays. The hint under the timeline says where a lossless cut will really start.
- 3
Trim and download
Leave Lossless selected for speed and perfect quality, or choose Exact cut if the start must be to the frame. Press Trim, check the preview, download.
What this tool does
- Lossless, keyframe-aligned cut by default: frames are copied, never decoded or re-encoded
- Exact cut mode re-encodes only the first and last second or so and copies everything in between
- Timeline with a filmstrip, keyframe ticks, draggable handles and editable timecodes
- The keyframe snap is shown in words, not just as a tick mark
- Output keeps the source container: MP4 and MOV become MP4, WebM and MKV stay as they are
- Optional “remove audio”, still lossless
- Keyboard shortcuts: I and O set the in and out points at the playhead
- Preview plays only the selected range
Cutting 12.5 s to 1:03.25 out of a 3-minute phone video
A 3 minute 12 second, 1.42 GB phone recording with a keyframe every two seconds. You ask for 00:00:12.500 to 00:01:03.250.
| Mode | Starts at | Ends at | Length | Re-encoded | Approx. size |
|---|---|---|---|---|---|
| Lossless, keyframe-aligned | 00:00:12.000 (0.5 s earlier) | 00:01:03.250 | 51.25 s | Nothing | 379 MB |
| Exact cut | 00:00:12.500 | 00:01:03.250 | 50.75 s | About 1.5 s at the start, 1.25 s at the end | 376 MB |
The sizes are the source’s 1.42 GB scaled by the kept duration (it is the same bitstream), so the lossless result is simply the frames you kept, plus a fresh container index of a few hundred kilobytes. Audio is cut at the nearest AAC frame boundary, about 21 ms at 48 kHz, and an edit list keeps it in sync with the first video frame.
Why a lossless cut snaps to a keyframe
A compressed video doesn’t store every frame as a picture. It stores a full picture (a keyframe, or I-frame) every so often, and in between it stores only what changed. A frame two seconds after a keyframe can only be decoded if you also have the keyframe and every frame between them. So if you cut at a frame that isn’t a keyframe and copy from there, the first frames have nothing to build on and the player shows garbage, or nothing, until the next keyframe arrives.
That leaves two honest choices. Lossless moves the start back to the keyframe at or before the time you asked for and copies from there: fast, perfect quality, and up to one keyframe interval (often 1 to 2 seconds on phone footage, up to 10 seconds on screen recordings) earlier than you clicked. Exact decodes the few frames between your requested start and the next keyframe, re-encodes just those with matching settings, and copies the rest untouched. The tail is handled the same way. Either way ClipHeron prints the actual start time and the difference, so there is no guessing.
Why a WebM comes out as WebM
A lossless trim copies the compressed video and audio exactly as they are, and each container only accepts certain codecs. MP4 and MOV hold H.264, HEVC and AAC happily, so they become a standard MP4. WebM holds VP8, VP9 and Opus, which don’t belong in an MP4 that every player will open, so a WebM stays a WebM and an MKV stays an MKV. The page tells you this on the file card and offers to convert to MP4 first; that requires encoding, so it is a separate step by design.
In this version the trimmed file is always an MP4: H.264 from an MKV or WebM is copied into it losslessly, while VP8 or VP9 video has to be re-encoded to H.264 because MP4 players don’t accept it.
Shortcuts and precision
With a handle focused, the arrow keys move it by one frame, Shift+arrow by one second, Page Up and Page Down by ten seconds, Home and End to the start and end. While the preview plays, I sets the start and O sets the end at the playhead. On a touch screen the handles are 44 pixels square and each has nudge buttons beneath it. You can also type a timecode such as 01:03.250 directly.
Variable frame rate recordings (most screen recordings) keep their original timestamps, so a range of “50.75 s” really is 50.75 seconds of wall-clock time, not a frame count divided by a nominal rate.
Good to know
- Long-GOP screen recordings may have a single keyframe at the start. Lossless mode can then only begin at 0; the hint says so and recommends Exact cut.
- The output is never bigger than the kept range of the source plus a small index. A size that looks “wrong” usually means the lossless start moved earlier than expected: read the hint.
- Several ranges in one pass (“keep these parts”) is on the list for a later release; for now, trim each part separately.
- Protected (DRM) files are refused. Files that are truncated or still being written by a camera show a specific message instead of a corrupt result.
Related tools and guides
Questions people ask
Does trimming lose quality?
Not in Lossless mode: the frames you keep are copied exactly. In Exact cut mode, only the opening and closing second or so are re-encoded, at settings matched to the source; everything in between is still a copy.
Why can’t I start exactly where I clicked?
Because a lossless cut must begin on a keyframe. The hint under the timeline shows the real start and how far it moved. Switch to Exact cut if the start has to be to the frame; it costs a second or two of re-encoding.
Can I cut several parts and join them?
Not yet. Trim each part separately for now; joining ranges losslessly is planned for a later release.
Why is my MKV or WebM output not an MP4?
A lossless cut copies VP9 or Opus streams as they are, and those don’t belong in an MP4 that every player opens. Use Convert to MP4 first if you need an MP4; that step has to encode.
Is my video uploaded?
No. The trimmer runs in your browser, reads the file from your device and writes the result back to it. We never receive the video or its name. See how it works for a test you can run yourself.
What about the audio at the cut points?
Audio is cut at the nearest AAC (or Opus) frame boundary, about 21 ms, and an edit list in the output keeps the first second in sync to within one audio frame. You won’t hear the join.
What happens to your video
Processed on your device. Your video is never uploaded. ClipHeron runs in your browser. We don’t receive your videos, their names or anything in them. Ads on this page load separately and are not given your files.
The trimmer reads only the parts of the file it needs through ranged reads and writes the new file to the browser’s private temporary storage, which is cleared when you download, clear or close the tab. Nothing is decoded in lossless mode, so no frame ever becomes a picture in memory. Your mode choice is remembered in local storage; the file, its name and the range you chose are not.
The page does load advertising and analytics scripts, separate from the tool and described in our privacy policy. They are never given your files.