[Roman T]

Some things I recently began wondering about..


1. looking at different pre/pros, a quote from the Thule 350B page caught my eye: (well, actually it caught John the Depot Dude's eye, but nevermind )


"Many new DTS DVD-releases are recorded with 24-bit resolution, like "Gladiator", "Jurassic Park III", "Pearl Harbour", and "Moulin Rouge". Due to its amazing processing power, the PR350B can decode DTS 24-bit stream to give..." bla bla blah (marketing buzzwords follow).


My question is:

Do those dvds really contain 24-bit resolution dts tracks?

I thought all dts dvds were 16bit?



2. Regarding DTS-ES discrete.

I complained on the Meridian forum about the lack of dts-es support.

Upon which Stacey Spears replied that decoding such a track causes audible artifacts due to the removal of the matrixed 6th channel data in the 2 surround channels.

Now, this caught me by surprise, as up until now I've heard mainly raving views of dts-es discrete.

Are there specific examples of software/equipment where those audible artifacts can be heard?



Thanks!

 

[sdurani]

Roman,
Quote:

Do those dvds really contain 24-bit resolution dts tracks? I thought all dts dvds were 16bit?

DTS works off a variety of masters, some really are 24-bit. However, after discarding significant amounts of data during the lossy compression process, who knows what the equivalent resolution would end up being at any given moment in the soundtrack (compression amount and technique can vary).
Quote:

Regarding DTS-ES discrete...decoding such a track causes audible artifacts due to the removal of the matrixed 6th channel data in the 2 surround channels.

Believe it or not, that's technically correct. However, I doubt most people could spot specific artifacting without being able to compare the ES 6.1 soundtrack to the original 6-channel discrete mix (which doesn't have the surround-back content mixed into the L&R surround channels).


When the DTS process compresses the original data, it uses a variety of techniques. One of these techniques is perceptual coding, where less audible sounds can be discarded when they are being "masked" by more audible sounds; the theory being that we'd never miss the discarded sounds (and in fact this actually works quite well). This compression occurs after the mix; i.e., the surround-back content has already been mixed into the L&R surrounds.


During the compression process, it is possible that particular sounds in the surround-back channel were masking sounds in one or both of the surround channels. If you listen to this soundtrack over a 5.1 system, no problem: the surround-back content is still mixed into the L&R surrounds. But what if the surround-back content is subtracted form the L&R surround content, as is done during ES decoding on a 6.1/7.1 system? Oops, suddenly you don't have sounds from the surround-back channel masking the discarded data in the L&R surrounds.


Is this a problem in the real world? I doubt it. Besides, a problem like this on DTS ES Discrete 6.1 soundtracks would also occur on regular DTS ES (matrix) as well as DD EX soundtracks, as both processes remove surround-back content from the L&R surround channels during decoding. There are reasons for being suspicious of the claimed "benefits" of the ES 6.1 format, but this isn't one of them. And it's certainly not a good excuse for why a modern processor should have DTS ES and DD EX, but not ES Discrete 6.1 decoding.


Finally, think about matrix encoded DD 2.0 soundtracks being played back via a matrix decoder. After subtracting out the centre AND surround channels, you'd think all sorts of masking artifacts would be audible. Never happens.


Best,

Sanjay

 

[Roman T]

Sanjay,


Thanks for your lengthy and thorough reply

It's really helped me understand these issues, and is greatly appreciated.


Regards,

-Roman