Yeah LW does not seem to recognise mp4 & mkv formats as being video formats yet. mkv is simply a containor format similar to avi & mov. 'Any' video & audio format could be inside. Video might be divx, h.264/x.264, etc. Audio might be mp4, mp3, aac, mp4, ac surround, etc. In most cased I'd guess the mkv video format is X.264. You might need to get such a codec. mkv though been around for a few years, is only starting to become popular now with high definition video. Also, mp3 is not always recognised as a video audio format (though DivX have been using it for years.)

Check http://www.gnutellaforums.com/downlo...tml#post320511 & where to get X.264 codec. I suggest X.264 because it has advanced much further in development than some of the other H.264 sources such as QuickTime's H.264. MPeg Streamclip might be a go to help you also. Also, perhaps take a look at MKV & consider MKVToolnix/iMkvExtract, & Handbrake - MKV II (program links under point #1) there should be windows versions also.