Bingowings said:
... MKV versions of these projects. ... wouldn't play on his PC or his media player.
The MPC-HC (an open-source media player) http://mpc-hc.sourceforge.net/ with the Matroska Media Container (an open-source MKV container) http://www.matroska.org/ will get these files playing nicely on the PC. (Depending on the version of Windows, an earlier version of the player might be used for compatibility; see its changelog for all released versions.)