Video Cutter
Trim video clips by selecting start and end timestamps. Choose instant stream copy or frame-accurate re-encoding with full privacy right inside your browser.
MP4, WebM, MOV, MKV, AVI, FLV, 3GP · up to 1 GB
Tips
- On first use, the browser downloads approximately 30 MB of core engine files, which remain cached for offline use.
- Fast cutting copies video streams without re-encoding in seconds, but cuts snap to the nearest keyframe.
- Choose re-encoded cutting when you need frame-accurate boundaries, though rendering takes longer on your device.
How to use it
- 1 Select or drag and drop your video file into the designated area.
- 2 Set the start and end cut points using the timeline markers or timestamp inputs.
- 3 Choose fast stream copy for instant cutting or re-encode for frame-exact precision.
- 4 Start the trimming process and download the exported video file.
What you should know
Trimming video requires balancing processing speed against cutting accuracy. Video formats like MP4 and WebM rely on inter-frame compression, storing complete keyframes (I-frames) every few seconds and predictive delta frames (P-frames and B-frames) in between. When you cut without re-encoding, termed stream copying, the software preserves original bitrates, colour depth, and audio tracks with zero quality loss. However, cuts must align with keyframe boundaries. If you demand exact timecodes down to the millisecond, the software must decode and re-encode surrounding frames, which calculates new pixel values and allows custom target dimensions or bitrates.
This tool processes your video entirely within the browser using WebAssembly. Select your start and end points directly on the playback timeline or input explicit timestamps. The fast stream copy option outputs your trimmed video almost instantly by extracting intact frame packets without altering codecs. Switching to re-encode mode recalculates the GOP structure to ensure frame-exact cut points. Note that browser-based rendering runs on a single CPU thread, so re-encoding high-resolution 4K or high-frame-rate files can take multiple times the clip duration. Container metadata and extraneous subtitle tracks may be discarded during export.
Frequently asked questions
Why does the fast cut start slightly before or after my selected time?
Fast cutting does not re-encode video data, so it must split the file at the nearest keyframe (I-frame). To trim at an exact millisecond regardless of keyframe placement, enable the re-encoding option.
Does trimming reduce the visual quality of my video?
If you select fast stream copying, video quality remains identical to the original because no compression occurs. If re-encoding is selected, the video is compressed again, which may result in minor generational loss depending on encoder settings.
Why does re-encoding a video take several minutes in the browser?
The WebAssembly processing engine executes locally on a single CPU thread inside your browser tab without hardware GPU acceleration. Complex codecs, high resolutions, and long durations require significant mathematical computation per frame.
Guides
Articles and format references related to this tool.
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