WMV to MP4 converter

Windows Media videos need to become MP4 to play on Macs, phones and in browsers. Your files stay on this device.

Drop WMV files here Files, a whole folder or a ZIP. Nothing leaves your device.

How to convert WMV to MP4

  1. Add your files. Drop WMV files anywhere on the page, or use Choose files. Folders and ZIP archives work too; every WMV inside is picked up.
  2. Check that MP4 is selected. MP4 is already chosen on this page. Other formats in the same row are one tap away if you change your mind.
  3. Adjust options if you need to. Leave quality on Original to copy streams when possible, or pick High, Medium or Small file and an optional resolution.
  4. Convert and download. Press Convert. Each file shows its progress, then a Download button. With several files, “Download all” gives you a single ZIP.

What happens to your WMV

A video file is a container holding a video stream and an audio stream. With the quality option on Original, Myriadfile checks what is inside your WMV: if the video already uses H.264 (or HEVC), it is copied into the new MP4 untouched. That is a remux: no quality is lost and it finishes quickly, even for long files. If the codec does not fit MP4, the video is re-encoded to H.264 with your browser’s built-in encoder, which can use your graphics hardware. Audio is copied when it is already AAC and re-encoded to AAC otherwise. WMV is not a format browsers can read, so Myriadfile first opens it with FFmpeg compiled to WebAssembly. That engine is about 32 MB and downloads once, the first time you convert one of these files; after that it is cached.

Choose High, Medium or Small file to always re-encode, for example to shrink the file or to get H.264 for older Windows PCs that cannot play HEVC. The resolution option scales the picture down to 1080p, 720p or 480p.

About WMV and MP4

WMV: WMV is Microsoft’s older video format. Macs, phones and browsers usually cannot play it.

MP4: MP4 is the most compatible video format. With H.264 video and AAC audio it plays on phones, TVs, browsers and every editing app.

Questions

Is my WMV file uploaded anywhere?

No. The conversion runs inside this browser tab using code served by this site, and the MP4 is created on your device. You can even disconnect from the internet once the page and its converter have loaded.

Will the MP4 lose quality?

Not when the streams can be copied: with the quality option on Original, a compatible WMV is remuxed into MP4 without re-encoding, so the picture is identical. When the video must be re-encoded, High keeps it visually very close to the original.

Can I convert several WMV files at once?

Yes. Drop as many WMV files as you like, a whole folder or a ZIP. They convert one after another, and “Download all” saves every MP4 in one ZIP that keeps your folder structure.

Is there a file size limit?

There is no fixed limit, because nothing is uploaded. The practical limit is your device’s memory: a phone may struggle with very large videos that a laptop converts easily.