Browser-Side Video Trimmer
Trim a video with browser-side start and end controls. The FFmpeg engine is hosted with the site and loads only after you start processing.
A video trimmer cuts a selected time range from a source video.
This first version is best for short MP4 or WEBM clips under 200MB.
Use a short source clip
Browser-side FFmpeg uses local memory and CPU, so smaller files finish faster.
Choose a clear time range
Fast trim is quickest, while MP4 or WebM re-encoding is better for exact boundaries.
Drop video here or click to upload
MP4 and WEBM are the safest first-version inputs.
Max file size: 200MB
No video uploaded
Mobile processing guidance
On mobile, test a short MP4/WebM and a 5-10 second range before trimming longer clips.
Max 200MB in this browser version.
Accurate MP4/WebM trimming re-encodes and can use much more mobile memory than Fast trim.
If trimming stalls, stop and retry with a shorter range or Fast trim.
Before trimming
Use files under 200MB. For mobile, test a short clip first.
Output choice
Fast trim is quicker; accurate MP4/WebM re-encodes and can take longer.
Failure causes
Unsupported codecs, memory pressure, very long ranges, or low mobile resources can fail.
Fast trim is quickest for MP4/WebM clips. Re-encoding is slower but better when you need more exact boundaries.
Trim accuracy note
Fast trim may start near the closest keyframe instead of the exact second. Use Accurate MP4 or WebM when the boundary matters, and keep mobile clips shorter to reduce memory pressure.
Keeps the original streams. Faster, but the cut may align to a nearby keyframe.
Clip length
0:10
Engine
ffmpeg.wasm
Output
Original container
Next step
Choose a video first. For mobile testing, start with a short MP4/WebM before trimming heavier files.
Output size
No trimmed clip yet
Range
0:00 - 0:10
Mode
Fast trim
FFmpeg is designed to run inside the browser after you start trimming, so the initial page stays light and the large WebAssembly engine is not loaded until needed.
Expecting exact-frame fast trim
Fast trim can snap to nearby keyframes. Use MP4 or WebM re-encode mode when exact start and end points matter.
Trimming very large files on mobile
Browser FFmpeg uses local CPU and memory. Shorter source clips are more reliable, especially on phones.
Forgetting output workflow
A trimmed clip may still need compression, format conversion, or thumbnail extraction before publishing.
Fast trim for quick cuts
Copies streams without re-encoding, which is faster and preserves quality.
MP4 for broad compatibility
Re-encodes the selected range to MP4 with H.264 video and AAC audio.
WebM for browser-native sharing
Re-encodes to WebM when the destination supports modern browser video.
Suggested workflow
Build a browser-side video prep workflow
Inspect the clip, trim the useful range, then extract or optimize the visual assets that support publishing.
Guides and examples
Use this tool in a real workflow
How is the video trimmed?
The selected video is designed to be processed in your browser with ffmpeg.wasm based on the current public implementation. Avoid sensitive files unless you have reviewed the implementation.
What is fast trim?
Fast trim copies the original streams without re-encoding. It is quicker and preserves quality, but the cut may align to a nearby keyframe.
When should I use accurate MP4 or WebM?
Use accurate re-encoding when you need cleaner start and end points or a predictable MP4 or WebM output. It is slower and uses more browser memory.
What file size should I use?
The first browser-side version accepts videos up to 200MB. Smaller clips are recommended on mobile devices because ffmpeg.wasm uses local memory and CPU.
Is this the same as video compression or conversion?
No. This page focuses on cutting a clip from a video. Compression and format conversion are separate workflows because they need different quality, bitrate, and size controls.