WMV to MP4 Converter

WMV is Microsoft's Windows Media Video format, used by old Windows Movie Maker projects, early digital cameras, screen-capture tools and many downloads from the 2000s. Phones, Macs, smart TVs and video sites often cannot play it. This converter re-encodes WMV files to H.264 video with AAC sound in an MP4, which plays practically everywhere. It runs in your browser with the ffmpeg engine (about 30 MB, downloaded the first time); your files are never uploaded.

How to use this tool

1. Choose the quality, an optional maximum resolution and deinterlacing.
2. Choose one or more .wmv (or .asf) files; conversion starts right away.
3. Wait for the progress bar: WMV is always fully re-encoded.
4. Play the MP4 in the page and download it (several files come as one ZIP).

Formula

Output = WMV 7/8/9 or VC-1 video → H.264 (x264, CRF 18–26) + WMA sound → AAC 160 kbps, in an MP4

No browser decodes WMV, and MP4 cannot hold Windows Media streams, so the picture and the sound are always converted. The engine has decoders for WMV 7, 8 and 9 (including VC-1 Advanced Profile and WMV 9 Screen), WMA, WMA Pro and WMA Lossless. CRF is constant quality: lower numbers give better pictures and bigger files.

Example

A 10-minute WMV at 640 × 480 and 30 fps has 18,000 frames. At about 27 frames per second (480p-class speed) the conversion takes roughly 11 minutes on a recent computer. A 720p WMV runs at about 12–13 frames per second, so the same length takes about 24 minutes.