Make web videos playable on standard media players. Every conversion runs locally on your Mac — your WEBM files are never uploaded.
macOS 14 or later · Apple silicon · Free to try
WEBM is an open video format built for the web. MP4 is the universal video format that plays on virtually every device. Make web videos playable on standard media players.
PrivateRemix handles the WEBM-to-MP4 conversion in a couple of clicks, with the result saved right next to your original file.
Unlike free online converters, PrivateRemix has no server. Your WEBM files stay on your Mac — no upload, no cloud, no account.
Drag a WEBM file into PrivateRemix, or pick one from your Mac.
Select MP4 from the formats PrivateRemix offers for your file.
The new MP4 appears next to the original. Nothing leaves your Mac.
The change is minimal. Both formats are compressed, and PrivateRemix converts at a high quality setting so there is no visible or audible drop for everyday use.
WEBM is designed for browsers and isn't natively supported by QuickTime or many editors. Converting to MP4 makes it play in almost any player.
For sharing and playback, yes — MP4 is supported by nearly every phone, TV, browser and editor, which is why it's the safe default.
No. PrivateRemix runs entirely on your Mac using its own processor. Your WEBM files never leave the device — there is no server to upload to, and it works fully offline.
Yes. Drop in a batch of WEBM files and PrivateRemix converts them all locally, saving each new MP4 next to its original.
Free to try. macOS 14 or later, Apple silicon.