How to convert MKV v4 to MKV v3 or v2 and retain same quality?

hello,

i just found this forum via google and found it very helpful, so i believe i will get the help from you guys.

i have samsung LED tv and i play movies and video songs on it, unfortunately it does not support mkv profile 4 or higher format and i have some important files/videos to play,

so how can i convert mkv profile 4 video to mkv profile 2 or 3 and retain the same HD 1080p quality?

Thanks in advanced.