As you can see in the logs... your file declares no audio track.
So either it doesn't have one or it is badly muxed and the problem is that vlc needs this info to know what decoder to use.
If the audio is greyed out the file announce no audio track or a track vlc can't play.
Can you open tools->messages set verbosity to two, start playback and paste the logs?
For mkv playing I suggest you to try vlc 2.0-rc1 from http://nightlies.videolan.org/build/win32/?C=M;O=D You may also want to check if the preload-local-dir option is checked in tools->preferences show setting=all input/codecs->demux->matroska If it's checked and your file is in a directory with man...
So now, it all works.. except that ass subtitles render badly most of the time, and for 10bit video I get thousands of [0x7f7e6633c2d8] main blend error: blending RGBA to I0AL failed errors. Oh well. [This thread can be closed] Blend has been rewritten two days ago, if you recompile a vlc from git ...
Beware there is still a known bug in mkv parser related to the caching duration. Each time you seek in the file you will lose audio for the duration of the caching. A fix is being written but may not be integrated for the release.
First you apparently modified your preferences because vlc shouldn't use avformat by default to demux mkv. If you are using a packaged 2.0-rc1 you can either reset your preferences or go into tools->preferences show settings=all then Input/Codecs->demux and reset the demux module to "predefined...
Is it ponctual macroblocking always at the same time for the same file and after some time it gets back to normal? Or from some point your file is unwatchable? If it's the first one, then you'll have to upgrade your vlc as this bug has already been corrected. For the second case : Can you open tools...