DTS and Dolby Digital (1 Viewer)

[Robert AG]

You are quite right. However I also said somewhere in one of those threads that while I preferred DTS, I knew why I did, and it had nothing to do with the DTS codec itself, but rather with the way the sound was altered. I just liked their EQ and the way the surrounds were pumped up. There was also a comment in there somewhere where I said that the DTS was smoother. It could have been that the DTS was genuinely smoother sounding in the LOTR DVD that I was listening to in that particular thread. This could have been the result of the DTS codec or of the EQ - I didn't delve that far into that particular finding at that time.

Do keep in mind that my work does not concern the sound quality of the finished DVD's of films I work on. I am only concerned professionally with maintaining quality from the original music scoring sessions through the final film mix. Any interest or experimentation on the sound contribution of lossy codecs is as a listener, just like you. The only difference is that I have a few more resources available, like the masters.

If you search around, you will also see a report on a direct Dolby Digital verses DTS verses original 35mm magnetic film master shootout that took place on a dubbing stage. This was done privately for a film director who was interested in what the differences in sound quality between them were, so that sound format release decisions could be made. I was one of a few people at this shootout. In this particular instance, there was essentially no sonic difference between the compressed formats, nor between them and the 35mm magnetic film Dolby SR master!

I guess it all boils down to being able to spot sonic manipulations verses sonic degradation. They are very different animals, and digital processing when it does degrade the sound does so in ways that do not effect the timbral balance or volume levels of the source. Digital degradation is easy to spot when you have enough exposure to it, as are the various sonic manipulations that are possible. I process digital sound as part of my work, and I manipulate sound by EQ, compression or any number of ways, so I am familiar with the sonic effects of both of them. In the subsequent direct comparisons I have done between my master copies and the released DVDs, the sound quality differences due to the codecs are easy to spot, as are the sonic manipulations that have been made, and it is easy to seperate them.

 

[RobertR]

Excellent discussion. It helps illuminate a point that a number of people have made over the years with respect to sound comparisons on various media, namely, that you cannot say that just because you prefer the sound of something, that it's automatically more accurate to the source. Preference and accuracy are two different things.

 

[David Judah]

It sounds like then you leave room that some of the differences between them are because of the codecs themselves and not just things in the production chain?


DJ

 

[Robert AG]

The comparison shootout was with the theatrical codecs.

Yes, I don't eliminate the possibliity that there are genuine differences in sound between the codecs. However I have found that in the vast majority of instances where I have made comparisons, the differences that were directly attributable to manupulation of the sonic character through things like EQ were obvious, and that this alone would make any objective comparison meaningless. If I could have stripped off that layer of sonic manipulation and have been assured that both encoding cycles were otherwise identical, then a truly valid comparison could be made.

One thing is certain however, and that is that in the comparisons I have done, the Dolby Digital presentation has been essentially unaltered when compared to my copy of the master. The DTS presentations have almost always been sonically altered in some manner.

 

[David Judah]

That is puzzling, since from what I understand, the studios are mostly doing the work themselves, not DTS. I wonder if it might be something in the encoder itself.

Interestingly, I've heard some in the industry observe the opposite--that is, DTS preserves more of the original's character, especially in regard to openess and dynamic range. The different reports makes it all the more confusing to us end users. I'm not disputing what you are saying, but I do find it curious.

Hopefully, we'll see some lossless compressed soundtracks for HD-DVD and Blu-Ray so we can hear more of what you hear when you are doing your work and the concerns over the lossy codecs will be a thing of the past.

DJ

 

[Robert AG]

Of course the debate can be fanned forever if that is what is desired. I would encourage you to seek out someone who encodes DVD sound at an authoring house and try to sort out the differences yourself if interested.

All my experience points to them both sounding pretty much equal at the end of the day, and both of them degrading the sound relative to the original 24 bit/48Khz elements - which was my original point.