Is my video uploaded during conversion?

No. ffmpeg.wasm runs entirely in your browser. Your video is processed locally and never sent to any server.

Does it work on mobile?

Yes. Works on iPhone Safari and Android Chrome without installing any app.

MP4 (H.264) is the most universally compatible format. It plays on every device, browser, smart TV, and media player.

WebM is the preferred format for web video — it is open, royalty-free, and natively supported in all modern browsers.

Re-encoding always involves some quality loss. This tool uses CRF 23 with the ultrafast preset, which provides good quality at reasonable file sizes.

Convert video files between MP4, WebM, and MOV formats entirely in your browser.

100% client-side · no upload

Video file (MP4, WebM, MOV, AVI…)

Settings Output format

Load a file to begin.

Choose your video file. Most common formats (MP4, WebM, MOV, AVI, MKV) are accepted.
Select the output format. MP4 for universal compatibility, WebM for the web, MOV for Apple tools.
Click Convert video. Conversion re-encodes the video — larger files take longer. Download the converted file.

Is my video uploaded during conversion?: No. ffmpeg.wasm runs entirely in your browser. Your video is processed locally and never sent to any server.
Does it work on mobile?: Yes. Works on iPhone Safari and Android Chrome without installing any app.
Why convert to MP4?: MP4 (H.264) is the most universally compatible format. It plays on every device, browser, smart TV, and media player.
Why convert to WebM?: WebM is the preferred format for web video — it is open, royalty-free, and natively supported in all modern browsers.
Will converting reduce quality?: Re-encoding always involves some quality loss. This tool uses CRF 23 with the ultrafast preset, which provides good quality at reasonable file sizes.

Last updated: 2026-05-20 By jarvisbox