What's the Best Firefox-64 Multimedia Plugin?

[Jonathan Ryshpan]

Flash is not available for Firefox-64.  But there are several frameworks
that play (just about) everything that Flash will, in particular
mplayer, xine,and gstreamer.  There are plugins for mozilla that rely on
these frameworks: gstreamer via totem and mplayer.  Probably also on
xine.

Are there others plugin methods?  Which is best (in your opinion)?

Thanks - jon