How it works
- 1Upload MP4, MOV, WEBM, or MKV
- 2Pick WebM (alpha for the web) or MOV (ProRes 4444 for editors)
- 3Keep existing alpha, or chroma-key green / blue / white / black / custom
- 4Preview on a checkerboard (WebM) and download
VoiceKitNeed an opaque MP4 instead?Free online tool
True transparent video
Export VP9 WebM with alpha, or ProRes 4444 MOV. MP4/H.264 cannot be truly transparent.
If the source already has alpha, keep it. If it is a solid-color backdrop (green, white, black), key that color out. Do not expect an H.264 MP4 to become see-through.
Make a transparent video
Choose WebM (web/overlay) or MOV (editing). Then keep existing alpha or key out a solid background.
- MP4
- MOV
- WEBM
- MKV
H.264 MP4 has no alpha. WebM VP9+alpha plays in Chrome/Firefox; ProRes MOV is for editors.
Ready — drop a file below.
Why this is not MP4
WebM VP9 + alpha
Browser-playable overlay with a real alpha channel. Requires -auto-alt-ref 0.
ProRes 4444 MOV
Editing format with alpha for Premiere / Final Cut. May not preview in the browser.
Solid-color key
H.264 sources have no alpha — key out green/white/black to create one.
FAQ
Why can’t you just make my MP4 transparent?
Standard H.264 MP4 has no alpha plane. The pixels are opaque. True transparency needs a format that stores alpha, such as VP9 WebM or ProRes 4444.
My clip is on a white or green background.
Choose that key color. Similarity controls how close a pixel must be; blend softens the edge.
The source already has transparency.
Set background key to “Keep existing alpha” so we re-encode without chromakey.
Safari / iPhone?
VP9 alpha is most reliable in Chrome and Firefox. For Apple editors, download the ProRes MOV.