I bet the other player you mention is the earlier version of Windows Media Player.  Some of that ActiveX code is still on most computers.  In your example it was probably installed when tried various codex packages.  I have a lot of old content with no way to view it, even on this WindowsXP machine and so downloaded Quicktime Alternative.  It displays content in Windows Media Player Classic.  I didn't even know that old thing was still part of my system.

MPC was good, clean, code, without all the merchant links and crap they put into their newer versions.  It is a fast efficient media player.

Well, best wishes to you,
Rªnce