I don't want to write it again so here is the post I had addressing the conversion...it lists the program you would need (freeware) along with the procedure that works!
after much research, I have come to the following conclusion:
At present my LE46B650T3W will never stream HD MKV from DLNA.
So what I've done is convert them to MPG using MKV2VOB, (superb streaming on WINDOWS MCE7 + extender by the way).
The MPG image is fine but plays like in fast forward without sound. I checked several files, and the only one that plays properly with sound is a 25 FPS with 384Kbps AC3 audio.
So could anyone at SAMSUNG possibly please update firmware ver.T-CHL7DEUC-2005.0 to enable 23.976 fps streaming with 448 or 640 Kbps.
thans in advance