Video Trimmer — Cut Clips With Zero Quality Loss

About this tool

WRRK's video trimmer uses ffmpeg.wasm to run the same trimming command you'd type into a terminal — but locally, inside your browser. The default command is ffmpeg -ss start -i input -t duration -c copy out.mp4: FFmpeg seeks to the start time, copies bytes for the duration, and writes a new container. No frame is re-encoded, so the output is identical in quality and the operation finishes in seconds.

The catch is that stream-copy can only cut at keyframes. If your trim start lands between keyframes, the resulting clip might begin with a black or frozen frame for a fraction of a second. The trimmer detects this case and falls back to re-encoding (H.264 / VP9 / AV1 depending on the input container), giving you frame-accurate cuts at the cost of a slower export. Either way, the file never leaves your device, works offline once loaded, and supports clips up to the limits of your browser's memory.

How to trim (5 steps)

1. Upload your video. Drop or pick a video file (MP4, WebM, MOV, MKV).
2. Find your clip. Use the preview player to locate the segment you want to keep.
3. Drag the trim handles. Set the start and end points on the timeline slider — accuracy is to one frame.
4. Trim. Click 'Trim'. Stream-copy mode runs in seconds; the trimmer falls back to re-encoding only if keyframes don't align.
5. Download. Save the trimmed clip to your device.

Use cases

• Cut a 30-second WhatsApp clip out of a long phone recording
• Trim trailing dead-air from a Zoom meeting export
• Slice a single highlight out of a livestream VOD
• Strip the intro/outro from a screencast before sharing
• Chop a podcast episode into shareable audiogram-ready chunks
• Make a short loop for an Instagram Reel or TikTok

Frequently asked questions