MKV to AVI

[Story Teller]

I have been searching this for as long as I can remember. But every time I find a program that changes MKV to AVI, problems come up like the video and sound doesn't go together, the video quality became pixelated or dull, and sometimes the file doesn't work.

Can anyone suggest a program I can use preferably something I can use for free? (I usually change MKV to AVI for purposes like putting it on tv using the PS3 or changing the AVI to Mpeg4 for Ipod)