Now that I’ve got my mythbox all setup properly (I screwed up LVM2 and lost all my data, twice, trying to remove harddrives … meh), I’m back to ripping my DVDs again. This time I’m using dvd2mkv, my custom little script I wrote, to do all the heavy lifting for my movies. But, there’s one thing I didn’t really put in there the first time around, and that’s support for alternate audio tracks.
Originally I wrote it simply to check automatically for the highest number of tracks and best audio format. As a general rule, that chooses the first channel that’s in English with 6 channels, which is always (in every case I’ve seen so far), Dolby Digital. If there is a DTS track, it’s always the second or third track behind it, but never gets selected automatically since it’s not the first one on the list. I can, however, select it if I run the program interactively. Not really ideal, of course, but it’ll have to work for now.
My real question though is, why aren’t there more movies with DTS audio tracks to them? Back in the day when I was working at a movie theater, one of my managers would swear up and down that DTS was better quality than Dolby. He would even make the projectionist screen the movies for him in the DTS theaters if the movie was equipped for it. He was quite the audio and videophile so I took his word for it. Now, though, you hardly see it anywhere. The only DVDs I’ve seen them on are some Paramount and Fox titles, and even then it’s only the newer ones that have it.
What’s also really interesting, and I kind of assumed this, is that SDDS, Sony’s 8 channel format, is completely missing from a home theater setup. Good ol Sony, going off and making their own standard yet again.
Anyway, when I listen to DVDs with both tracks, I really can’t tell a difference myself. My receiver supports both DTS and Dolby, so I figure … why not, I’ll rip em anyway and see if it really is any nicer.
Well, if I understand the different formats correctly, here’s the deal:
* Dolby (in theatres) is limted to around 380 kbps, due to the way the dolby signal is stored (between the sprockets)
* DTS (in theatres) just has a time-sync code on the film; the actual audio is on CD-ROM, and has a much higher bitrate (in the thousands).
On DVD, however, things are different:
* Dolby isn’t as limited by storing the sound data on the film. Dolby on a DVD is at a higher bitrate than in theatres.
* DTS, on the other hand, is limited by DVD, and has a lower bitrate than in theatres.
Hence the difference between Dolby & DTS are smaller on DVD than in a theatre; it’s not surprising you can’t hear the difference.
Space is also important on a DVD: Dolby is required. DTS is optional. both take up space. So do you want to put on a redundant sound track, or ‘extra’ bonus material? Or do you want to shoot for a single-layer disc and save some production costs?
It once was explained to me by a movie / audio buff as well – and from what I remember, it is exactly as Pariah explained it. I concur wholeheartedly.
In movie theaters, DTS is the bomb. On DVDs, the difference, in my opinion, can only be discerned by the absolute most discriminating audiophiles while listening to a movie DVD on a system employing the absolute best hardware.
In other words, DD is all but synonymous to DTS in DVD-land.