The B5 geek in my badly needed a new ringtone and I decided to pull out all the stops and create a video ringtone (3gp file).  This tutorial will also help you to learn how to merge audio and video files with QuickTime.
Prerequisites
You will need QuickTime Pro. With QT Pro, you will create your file. For that, you of course will need a QT compatible video (preferably .mov or .mp4/.m4v) and audio file. I used the excellent tool iTube X to download a flash file from YouTube containing the opening …

Mac computers don’t play AC3 files natively so what to do? And how to add them to iTunes so you can sync them to your iPod or Mp3-player of choice?
First thing’s first: How to play those files? You need to download the A52 codec, that will enable Quicktime to play the files. Read the instructions in the »Readme«!
Now, I am running Mac OS Leopard and conversion did not work for me with mac3dec.1.6.3 – it worked fine under Tiger, but not anymore. Instead, I downloaded MpegStreamclip. Just load your AC3 …