Convert WMV to MP4

Convert WMV to MP4 online free: old Windows Movie Maker videos are re-encoded to H.264 MP4 that plays on every phone and TV. Many at once, no upload.

Drop WMV videos to convertor click to choose · MP4, MOV, MKV, AVI, WebM, WMV, FLV, 3GP, MTS · up to 3 GB each, many at once

Convert to

Quality

When the streams already fit the new format, they are copied as they are: a fast remux with no quality loss. Otherwise the video is re-encoded at high quality.

Maximum resolution

Keep the sound

WMV

WMV (Windows Media Video) came with Windows Movie Maker and old Windows phones and cameras. The picture is WMV or VC-1, the sound WMA.

Macs, iPhones, Android and browsers don’t play Windows Media, so every frame has to be re-encoded to H.264.

WMV to MP4: remux or re-encode

WMV can’t become MP4 without re-encoding: its picture codec isn’t one MP4 players read, so every frame is decoded and encoded again as H.264, with AAC sound.

WMV files are often large for what they show; at the Balanced preset a 1080p minute comes out around 30 MB. Files up to 3 GB are converted, and the FFmpeg path keeps the result in memory, so very long videos need a desktop browser.

How it works

Drop one or more WMV files: MP4 is already selected. Quality, maximum resolution and sound can be changed before you start.
Streams that fit MP4 are copied; anything else is re-encoded with WebCodecs, or FFmpeg compiled to WebAssembly when the browser can’t.
Download each file, or all of them as one ZIP.

Questions

Are my videos uploaded?

No. Reading, remuxing and encoding all run in this browser tab. Open DevTools and watch the Network tab while a file converts: no request carries it.

Why is one file done in seconds and another takes minutes?

A remux only copies the streams, so it runs at disk speed. A re-encode decodes and encodes every frame; FFmpeg in WebAssembly, used when the browser can’t, is slower still.

How large can a video be?

Up to 3 GB per file for free, and as many files as you like. Remuxes and WebCodecs re-encodes stream from the disk; the FFmpeg path holds the result in memory.