Example: make a square clip from a landscape recording
Suppose your recording is 1920×1080 pixels and you want a square clip centered on the subject. The largest square inside that frame is 1080×1080 pixels. A centered square starts 420 pixels from the left edge: (1920 − 1080) ÷ 2 = 420. Its top edge is at Y = 0.
Crop and download in four steps
- Open Crop Video and select a video file from your device. The tool accepts MP4, M4V, MOV, WebM and MKV containers when your browser can decode their tracks.
- Choose the 1:1 aspect ratio. The tool places the largest square crop over the video. Drag the frame to keep the subject inside it. For the centered example, expand Exact values and check X = 420, Y = 0, width = 1080 and height = 1080.
- Review the preview and Output plan. The default output uses the crop’s pixel size and MP4. You can select WebM under Output format if your browser supports its encoder.
- Click Crop video. When processing finishes, preview the result and click Download video.
What stays on your device?
The selected file is read and re-encoded locally in your browser. Its video bytes are not sent to a processing server. A completed service worker installation also makes the tool’s static resources available offline.
The video track is re-encoded, so processing time depends on the file and device. Audio is kept by default if its track can be decoded, or you can choose No audio. Subtitle tracks, chapters and private metadata are not carried into the exported file.
MP4 or WebM?
MP4 uses H.264 video and AAC audio when audio is kept. WebM uses VP9 video and Opus audio. Automatic output selects MP4. The output plan shows the selected format before you start; a missing browser encoder or unsupported source codec will prevent export. Try a supported browser or file if the tool reports a blocker.