I've not seen a single PAL DVD with a multi-channel MPEG-2 soundtrack. Even a stereo AAC soundtrack is rare. DTS is much more likely to be found, in fact. The

I've not seen a single PAL DVD with a multi-channel MPEG-2 soundtrack. Even a stereo AAC soundtrack is rare. DTS is much more likely to be found, in fact. The really interesting thing about AC-3 is how it is stored on a film reel. Back when it was developed, multi-channel audio was becoming a thing. For large format film (70mm), the solution was simple: 6 magnetic soundtracks. This actually far exceeds the quality of most cinema audio systems even today. But film companies wanted to get it on to 35mm film which the vast majority of cinemas could actually use. 35mm already has two optical soundtracks, and they didn't want to remove these and force cinemas to change their equipment. One solution was to have the soundtrack stored on some other medium and synch it together with the film. This the approach used by DTS. But Dolby developed a technique to print the soundtrack between the perforations on the side of the film, thus producing a film that is completely backwards compatible and even has an analogue backup which can be automatically switched in case the AC-3 got damaged. As is often the case with technology, it wasn't the highest quality format that won, it was the one that could be practically used at the time.