2. October 2010 16:28
After my last post, I continued to fiddle with my TVersity configuration. What I found was that the Shark007 codec packs really do the job.
Follow their instructions carefully. You'll need to remove all other codec packs (they recommend even uninstalling TVersity's built-in codec pack). Then install the 32-bit version, then the 64-bit version. After I did that, I could play anything (even MKV videos) through TVersity using the DirecTV MediaShare or with Windows Media Player. Since I haven't had good luck with Windows Media Center, I haven't gotten around to testing that again.
Another useful tool is the Win 7 Direct Show Filter Tweaker. It allows you to control which codecs are invoked by DirectShow clients, both 32-bit and 64-bit. It also allows control over the new Windows 7 "override" codecs (those used to create icons and play media through WMP and WMC). I used this to force my DVIX and XVID to play through ffdshow. Since Shark007 is really a repackaged version of ffdshow, you'll see that name among the alternative codecs for most of the popular video formats.
I haven't tried streaming Dolby or DTS since DirecTV MediaShare doesn't support anything but stereo (AFIK), so I can't vouch for that capability.
I did see TVersity die once, but I have a simple batch script that checks to see if it's running and restarts it if it's not. Time will tell how often this is necessary.