I've got a 15" Powerbook running 10.4.3, 1.67Ghz, 1.5Gigs of RAM. I'm having some problems with the sound looping/reverberating for about 5 seconds at a time when I watch DVDs or XviD videos. I believe it also happens if I'm playing mp3s, but it seems much less frequent (if at all, I can't remember for sure). During video watching it seems to happen about once every 20-40 minutes. It sounds like the audio is caught in about a .5 second loop while the regular sound continues to play, if I pause the video it immediately stops, and when playback is resumed the sound is normal. What may be the problem? What can be done to fix it?