Enable IE Tab (for Windows) or use an old version of Firefox with the legacy VLC Web Plugin. Warning: This is a security risk. Only do this on a virtual machine or isolated environment.

If you insist on using Windows Media Player or an older editing suite, you need the official Xvid decoder.

I have to pause here. When you search for "Xvid unblock," you will find shady sites offering "Xvid Unlocker 2026.exe" or "Codec Pack Cleaner."