Drop a .wmv file and get an H.264 MP4 that plays on any phone, browser, or TV — encoded on your device.
Drop a .wmv file and get an H.264 MP4 that plays on any phone, browser, or TV — encoded on your device.
Convert WMV files to MP4 in your browser. WMV (Windows Media Video) was the default for older Windows cameras, Movie Maker exports, and screen recordings. Macs, iPhones, and most browsers can't play it without extra software. GhostVideo re-encodes the video to H.264 with AAC audio in an MP4 container — the combination every modern phone, browser, smart TV, and editing app plays — using ffmpeg compiled to WebAssembly on your device. No upload, no signup, no watermark.
The encode uses a high-quality constant-quality setting (CRF 20) and the widely compatible yuv420p pixel format, so the result looks like the source without the playback problems older codecs cause.
How it works
Drag in the .wmv file. It opens in the GhostVideo studio with Convert to MP4 pre-selected.
ffmpeg converts the video to H.264 + AAC in your browser. Long videos take a while — the encode runs on your device's CPU.
Save the MP4, or keep going: trim, compress to a target size, or turn it into a GIF in the same tab.
About WMV
WMV uses Microsoft's Windows Media codecs, which have limited support outside Windows. H.264 MP4 plays natively almost everywhere.
Compress after converting
If the MP4 is still too big to email or post, run Compress, or Compress to 8 MB for Discord-sized uploads — it stacks on the converted file without re-dropping it.
No. The conversion runs entirely in your browser with ffmpeg.wasm — there is no server that receives your video.
Re-encoding is lossy in principle, but the encode uses CRF 20, a high-quality setting where the difference from the source is hard to see. The file is often smaller than the original too, because H.264 is more efficient than most older codecs.
Browser WebAssembly can't use your GPU's hardware video encoder, so a long or high-resolution video can take several minutes. Short clips convert quickly.
The practical limit is your device's memory, because the file is processed in the browser tab. Desktop browsers handle much larger files than phones; the tool tells you if a file is too large for your device.
MOV to MP4
Make iPhone and QuickTime footage play everywhere.
MKV to MP4
Turn OBS captures into standard MP4s that upload anywhere.
WebM to MP4
Convert screen recordings so iPhones and editors accept them.
Compress video
Shrink phone footage to shareable size — encoded on your device.
Trim video
Cut a clip down to the moment that matters, on a live preview.
Every GhostVideo tool runs entirely in your browser. Your file is never uploaded — there's no upload endpoint to send it to.