Some of my AVI files suddenly don't have sound. Even some that used to have sound before. They have sound if i move them to a PC computer, but not on my mac. I tried the A52 Codec, but still no sound. Some AVi files still have sound, but the ones I make with my camera dont. Any suggestions? All i've done to the computer recently is an itunes, a safari and a mac security update... i'm using a mac 10.4.11. Any help would be greatly appreciated.