MOV to WebM converter

Web developers convert iPhone and screen-recording MOVs to WebM for royalty-free HTML5 video and smaller page weight.

Drop a MOV file hereThe converter loads in your browser.

What happens to your MOV

H.264/HEVC video is re-encoded to VP8 and AAC audio to Opus. VP9/AV1 output is not available in the browser engine.

Tip: Serve WebM with an MP4 fallback: every modern browser plays H.264 MP4.

How to convert MOV to WebM

  1. Drop your MOV file on the box above, or tap it to pick one. The engine (about 31 MB) loads once per visit.
  2. The converter reads the file's streams and shows which codecs are inside.
  3. Keep the defaults, or pick a quality and resolution.
  4. Press the button, wait for the progress bar, then download your WebM.

Prefer the command line?

This is the FFmpeg command the converter runs for a typical MOV (hevc + aac). Paste it into a terminal with FFmpeg installed for batch jobs or files too big for a browser tab:

ffmpeg -y -i input.mov -map 0:v:0 -map "0:a:0?" -sn -dn -c:v libvpx -deadline realtime -cpu-used 5 -crf 20 -b:v 2M -pix_fmt yuv420p -c:a libopus -b:a 128k output.webm

This re-encodes, so expect it to take a while on long files. Your own file may contain different codecs; the converter above detects them and adapts. For other jobs, ask the FFmpeg command helper.

Questions

Does it keep transparency?

No. Alpha-channel MOV (ProRes 4444) loses transparency because VP8 output here has no alpha.

Is my MOV file uploaded?

No. The MOV is read from your device by FFmpeg running as WebAssembly in the page, and the WebM is written back to your device. No server ever receives it.

Is there a size limit for MOV to WebM?

We set none. The practical limit is browser memory: roughly 2 GB of output on a computer, and much less on phones.