Where WMV files still matter
WMV is the format that a generation of Windows software saved by default. Windows Movie Maker exported WMV, older versions of PowerPoint saved presentations as WMV videos, and company e-learning tools, webcams and screen recorders from that time used it as well. Many of those files are still in use: in training folders, on intranet pages, in slide decks and on digital signage players that run Windows.
If the file has to keep working in such a place, converting it to another format can break links and playlists. Compressing it to a smaller WMV keeps everything in place and saves disk space or bandwidth.
What the compressor writes
The compressed file uses Windows Media Video 8 for the picture and WMA for the sound. Windows Media Player and the Media Player app on Windows 10 and 11 play it, and so do older PCs, PowerPoint and most programs that accept WMV. Because no browser can decode or encode Windows Media codecs, the work is done by a built-in converter engine (ffmpeg compiled for the browser). It is slower than compressing an MP4, and the whole file has to fit in memory.
A WMV quirk: newer sources are already efficient
WMV files come in several codec generations. Files saved with WMV 9 or VC-1, common from the mid-2000s, are stored quite efficiently. Writing them again with WMV 8 at the same resolution saves less than you might expect. Sometimes the new file would even be larger, and then the tool gives you the original file instead.
The reliable way to make such a file much smaller is to lower the resolution or the frame rate:
- Presentation and lecture recordings look fine at 720p and 15 or 24 fps.
- Small clips for a slide deck often work at 480p.
- Old screen recordings with large areas of plain colour compress very well at any setting.
Use the 2-second preview to see how text on slides holds up before you compress the whole lecture.
When MP4 is the better answer
If the video doesn't have to stay WMV, an MP4 with H.264 is usually several times smaller at the same quality and also plays on Macs, phones and in browsers. WMV to MP4 converts it, and the MP4 compressor can shrink it further. To shorten a long recording or join several parts, use the WMV editor.
Files protected with Windows Media DRM can't be opened. Everything else is processed on your own computer, without uploading.