First, tell me when and where I talked about “matroska packs to play matroska files”. I said that Matroska containers can have audio streams coded in different ways, and for each coder (way) there must be appropriate decoder.
I don’t think this was directed at you, but caf4926. Sorry for the confusion.
Matroska isn’t a codec, it is a container that may require different codecs to be played.
I know full well what Matroska is 
I don’t know where you took an “codec packs should be AVOIDED” idea from, but you should better have left it there
Personally, I use K-Lite for more than 2 years, and my system (WinXP SP2) can not and was not “screwed up” with it. K-Lite Mega IS a codec pack, and it doesn’t modify any system critical files. It has anything I need for en-/decoding, and I don’t think about other.
No? Well, install it then use GraphEdit and open a file and you’ll probably see how much junk filters it has added to the graph. Indeed, if you install wrong filters, it can for example make the video appear flipped. I’ve experienced this before and I have been keeping tabs on this like this. If you would ask in a forum concerning this kind of things, I think they too would tell you to avoid packs. Use ffdshow instead.
BTW…
Now tell me these 9.5+M downloads have screwed up 9.5+M systems %)
Use anything you like for yourself, but don’t insist others should do the same when there are many alternatives.
Just let people make informed decisions by themselves.
It can work. Sometimes it won’t, and even if it does work it still probably installs a lot of junk filters that are added to the grraph.
Also, ffdshow has the advantage of a lot of options, like post processing (deblocking among them), noise reduction, volume normalization, etc.
And that’s why I recommend to stay away from them 