Hmmmm, okay thanks for that idea with .mp4, I may try that instead then. But in terms of the .wtv converted .mkv I may have to try it.
Currently I use the .mkv to dvrms profile and it works perfectly... I cannot tell the difference between a native recording and the converted .mkv during playback on the extender, it really is nice, smooth and playable. And these have been .mkv's from all sorts of different sources, no real consistency in terms of anything.
Why not just keep doing this you ask? Well although it doesn't take long, It's not speedy either. It sounds like the .mkv to .wtv profile is quite fast (although that is a relative term). Also there is more possiblility for meta data in the .wtv format than the dvr-ms.
If you doing the encode yourself then I understand why you would just go straight to .mp4, but if you are re-encoding .mkv's to .mp4 then I suggest you try the .mkv to dvrms instead. Thats just my two cents, and you have probably considered this already and did not go that route for some reason I'm not aware of.