I just started getting this problem yesterday with the sound while playing dvds and mkv files from my hard drive. Whenever i try to playback a vob or mkv file in VLC or Media Player Classic, i can hear the background sounds like music, cars, etc., but i can't hear the people talking. I have the K-lite mega codec pack and the ac3 filter installed also. It seems this is only when i try to playback dvd's and mkv's because everything is fine when i play avi files. The only software i have that will play them ok with the people talking is Nero Showtime 3. Need some help.