Play Speed Changing Not Available In All Formats???

Is there only a specific number of formats that can be played in the fast
mode, i.e. using Ctrl+Shift+G, as I have found the feature not to be working
on all formats, like FLV etc?

Sure would oblige if a way to overcome the problem may kindly be provided as
I have around 3 DVDs x 45 Hrs courses to be watched and the professors are
too much explaining and/or repeating most of the concepts and most but not
ALL the videos anyway are on the REAL VIDEO formats which I seek to be
playing on the WMP. Any codec available?-- Thanx & Best Regards,Faraz!