I really would like to know where I can get MKV converters for free? I now know that this file type can have HQ Avatar videos that wold make a good impression to Avatar Music Video viewers.
The best way to handle mkv files is to convert to lossless avi, but as paco said, recontainering works too, but I would not use yamb as they are better options. I'd usually post links to all you need, but I'm on my phone so I'll just link my guide for these two methods: Guide to handing MKV Files