Can someone tell me why or what a FLAC audio file is. OK, I know it's a high quaity audio format, but Perian which I recently downloaded thanks to your advice here, has been used to view AVI files, yet when I clicked on a FLAC file which is an audio file it brings up a box which says.. 'You are opening the application "Perian - Open in QT Player" for the first time. Are you sure you want to open this application?' This application is in a folder named "Resources". etc... I'm guessing the audio file can be played by Perian, but why is it now asking permissions to use it for playing audio when it's never asked for permissions to view AVI footage in QT before? Something I should know or...?